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Everything you need to know about Computed Tomography (CT) & CT Scanning

Kidney: Malignant Tumors Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Kidney ❯ Malignant Tumors

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  • “Myeloid sarcoma (MS), also known as “granulocytic sarcoma” or “chloroma”, is a solid extramedullary tumor mass composed of malignant primitive myeloid cells. By definition, the infiltrates efface the underlying tissue architecture. In the 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia, MS is described as a unique clinical presentation of any subtype of acute myeloid leukemia (AML). The etiology of MS is still unknown. Myeloid sarcoma may present de novo, accompany peripheral blood and marrow involvement, present as relapse of acute myeloid leukemia, or as progression of a prior myelodysplastic syndrome (MDS), myeloproliferative neoplasm (MPN), or MDS/MPN. Seldom precedes MS the development of the hematologic disease.”
    Myeloid Sarcoma Involving Kidneys: From Diagnosis to Treatment. Case Report and Literature Review
    Francesca Guidotti et al.
    CMI 2020; 14(1): 39-44
  • "MS radiologically appear as soft tissue masses on plain CT and as well-defined homogeneously enhanced masses on enhanced CT. Differential diagnoses of renal MS on CT mainly include insignificantly enhanced renal cell carcinomas, renal infarctions, and renal lymphomas. Unlike renal MS, insignificantly enhanced renal cell carcinomas are usually singular and prone to hemorrhage, necrosis, and cystic changes in the lesions. Renal infarctions are usually wedge-shaped with no mass effect and enhanced cortical rim signs representative of cortical rims and renal vessel abnormalities on the lesion side may be observed on contrast-enhanced CT images.”
    Myeloid Sarcoma Involving Kidneys: From Diagnosis to Treatment. Case Report and Literature Review
    Francesca Guidotti et al.
    CMI 2020; 14(1): 39-44
  • "When MS occurs as a presenting feature before the onset of overt leukemia, it is often misdiagnosed as lymphoma. A review of 72 patients of non-leukemic MS showed that 35 patients (47%) were initially misdiagnosed, most often (31/35) as malignant lymphoma. The morphological similarity of blasts with lymphoma cells, especially in the blastic and undifferentiated variant of MS and its rarity, resulting in low index of suspicion, have been reported as the main reasons for the misdiagnosis in such cases.”
    Myeloid Sarcoma Involving Kidneys: From Diagnosis to Treatment. Case Report and Literature Review
    Francesca Guidotti et al.
    CMI 2020; 14(1): 39-44
  • “Myeloid sarcoma is an extramedullary tumor of immature granulocytic cells. It is a rare condition, most often associated with acute myeloid leukemia (AML), although in some rare cases it may present in nonleukemic patients. It should therefore be considered as a differential diagnosis of any atypical cellular infiltrate. It may occur at any site, leading to very varied clinical presentations. Diagnosis is challenging and relies on a high index of suspicion as well as radiology, histology, immunophenotyping, and molecular analyses, which also are essential for risk stratification and treatment planning. Systemic chemotherapy using AML-like regimens should be commenced early, even in nonleukemic disease.”
    Myeloid Sarcoma: Presentation, Diagnosis, and Treatment.
     Almond LM et al.  
    Clin Lymphoma Myeloma Leuk. 2017 May;17(5):263-267
  • “Tumor cells are commonly arranged in a solid, nested, or tubulocystic pattern within variable amounts of loose edematous, myxoid, or hyalinized stroma. Tumor cells are polygonal with abundant granular eosinophilic cytoplasm, uniform round nuclei with smooth nuclear contours, evenly dispersed chromatin, and variably prominent nucleoli. Immunohistochemically, oncocytomas express CD 117, E-cadherin, pancytokeratin, and low molecular weight cytokeratins. CK7 is generally not seen but may be focal. Oncocytomas are usually sporadic and can be associated with Birt-Hogg-Dubé syndrome.”
    Review. Update on Renal Neoplasms: Clinicopathologic-Radiologic Correlation With Case-Based Examples
    Aida Valencia-Guerrero et al.
    American Journal of Roentgenology. 2020;214:1220-1228.
  • OBJECTIVE. The objective of our study was to systematically review the literature about the application of artificial intelligence (AI) to renal mass characterization with a focus on the methodologic quality items.
    MATERIALS AND METHODS. A systematic literature search was conducted using PubMed to identify original research studies about the application of AI to renal mass characterization. Besides baseline study characteristics, a total of 15 methodologic quality items were extracted and evaluated on the basis of the following four main categories: modeling, performance evaluation, clinical utility, and transparency items. The qualitative synthesis was presented using descriptive statistics with an accompanying narrative.
    RESULTS. Thirty studies were included in this systematic review. Overall, the methodologic quality items were mostly favorable for modeling (63%) and performance evaluation (63%). Even so, the studies (57%) more frequently constructed their work on nonrobust features. Furthermore, only a few studies (10%) had a generalizability assessment with independent or external validation. The studies were mostly unsuccessful in terms of clinical utility evaluation (89%) and transparency (97%) items. For clinical utility, the interesting findings were lack of comparisons with both radiologists' evaluation (87%) and traditional models (70%) in most of the studies. For transparency, most studies (97%) did not share their data with the public.
    CONCLUSION. To bring AI-based renal mass characterization from research to practice, future studies need to improve modeling and performance evaluation strategies and pay attention to clinical utility and transparency issues.
    Artificial Intelligence in Renal Mass Characterization: A Systematic Review of Methodologic Items Related to Modeling, Performance Evaluation, Clinical Utility, and Transparency
    Burak Kocak et al.  
    American Journal of Roentgenology 2020 215:5, 1113-1122
  • “Oncocytomas are benign epithelial neoplasms and account for 5–9% of all renal cell tumors. They usually present as a solitary cortical mass but multifocal and bilateral disease is not uncommon. Figure 4A shows a CT scan of the abdomen of a 3.8-cm oncocytoma with a central scar, arising in the right kidney. These tumors are tan to mahogany brown or yellow and are usually well circumscribed and unencapsulated. A stellate scar is frequently seen.”
    Review. Update on Renal Neoplasms: Clinicopathologic-Radiologic Correlation With Case-Based Examples
    Aida Valencia-Guerrero et al.
    American Journal of Roentgenology. 2020;214:1220-1228.
  • “For all these reasons, preoperative diagnosis of solid renal masses continues to challenge clinicians. In fact, differentiation between RCC and oncocytomas is usually made on the basis of histologic findings of the surgically removed tumor. To avoid unnecessary surgery in patients with benign lesions, preoperative diagnosis by imaging would be of great value.”
    Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model
    Blanca Paño et al.
    AJR 2016; 206:764–774
  • “Oncocytomas showed significantly higher enhancement than RCCs in the nephrographic and excretory phases, that is, N2 and N3 of oncocytomas were higher than N2 and N3 of RCCs (p = 0.02 and p = 0.03 for N2 and N3, respectively), and the same was true in lesions 4 cm or smaller (p = 0.03 and p = 0.004 for N2 and N3, respectively) (Table 2).”
    Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model
    Blanca Paño et al.
    AJR 2016; 206:764–774
  • “Our study suggests that the combination of homogeneous enhancement and the difference in attenuation for the excretory phase leads to a good level of correct classifications between RCC and oncocytoma. In addition, given that the tumor can be measured quickly and simply and the high (almost eightfold) increase in risk, a tumor larger than 4 cm should always trigger further study when imaging data is not available. Our study provides higher accuracy than that previously reported, because most studies to date have concluded that RCC and oncocytoma cannot be differentiated by analyzing each variable independently using MDCT. This higher accuracy could be attributable to the multiparametric analysis we performed.”
    Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model
    Blanca Paño et al.
    AJR 2016; 206:764–774
  • “We have not evaluated the presence of segmental enhancement inversion or the presence of a central, sharply marginated, stellate scar (commonly described as characteristic findings for oncocytoma) because these features have been found in both oncocytoma and RCC, particularly in the chromophobe subtype of RCC, and are therefore poor predictors of oncocytoma .Regarding the usefulness of the different phases, our study suggests that arterial phase imaging is not helpful to differentiate RCC from oncocytoma and that only unenhanced, nephrographic, and excretory phases are necessary.”
    Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model
    Blanca Paño et al.
    AJR 2016; 206:764–774
  • “In conclusion, this study indicates that the combination of parameters assessed using MDCT (size, homogeneity, and enhancement changes between the excretory and unenhanced phases) can help distinguish between RCC and oncocytoma. The phases that have proved useful for differentiation are the excretory and nephrographic phases; their differences in relation to the unenhanced phase also appear to provide helpful information. Our data should be confirmed and validated in a larger and independent cohort.”
    Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model
    Blanca Paño et al.
    AJR 2016; 206:764–774
  • OBJECTIVE. The objective of our study was to systematically review the literature about the application of artificial intelligence (AI) to renal mass characterization with a focus on the methodologic quality items.
    MATERIALS AND METHODS. A systematic literature search was conducted using PubMed to identify original research studies about the application of AI to renal mass characterization. Besides baseline study characteristics, a total of 15 methodologic quality items were extracted and evaluated on the basis of the following four main categories: modeling, performance evaluation, clinical utility, and transparency items. The qualitative synthesis was presented using descriptive statistics with an accompanying narrative. strategies and pay attention to clinical utility and transparency issues.
    Artificial Intelligence in Renal Mass Characterization: A Systematic Review of Methodologic Items Related to Modeling, Performance Evaluation, Clinical Utility, and Transparency
    Burak Kocak et al.  
    American Journal of Roentgenology 2020 215:5, 1113-1122
  • RESULTS. Thirty studies were included in this systematic review. Overall, the methodologic quality items were mostly favorable for modeling (63%) and performance evaluation (63%). Even so, the studies (57%) more frequently constructed their work on nonrobust features. Furthermore, only a few studies (10%) had a generalizability assessment with independent or external validation. The studies were mostly unsuccessful in terms of clinical utility evaluation (89%) and transparency (97%) items. For clinical utility, the interesting findings were lack of comparisons with both radiologists' evaluation (87%) and traditional models (70%) in most of the studies. For transparency, most studies (97%) did not share their data with the public.
    CONCLUSION. To bring AI-based renal mass characterization from research to practice, future studies need to improve modeling and performance evaluation strategies and pay attention to clinical utility and transparency issues.
    Artificial Intelligence in Renal Mass Characterization: A Systematic Review of Methodologic Items Related to Modeling, Performance Evaluation, Clinical Utility, and Transparency
    Burak Kocak et al.  
    American Journal of Roentgenology 2020 215:5, 1113-1122
  • “In this study, we systematically reviewed 30 studies about the application of AI to renal mass characterization. Our focus was on the methodologic quality items related to modeling, performance evaluation, clinical utility, and transparency. The quality items were favorable for modeling and performance evaluation categories for most studies. On the other hand, they were poor in terms of clinical utility evaluation and transparency for most studies. To move this field of research to clinical practice, future studies need to improve modeling and performance evaluation strategies by constructing their analysis on the robust features and finding ways to perform proper generalizability assessment with independent or external validation. In addition, forthcoming studies should pay attention to clinical utility and transparency issues.”
    Artificial Intelligence in Renal Mass Characterization: A Systematic Review of Methodologic Items Related to Modeling, Performance Evaluation, Clinical Utility, and Transparency
    Burak Kocak et al.  
    American Journal of Roentgenology 2020 215:5, 1113-1122
  • “Renal cell carcinoma (RCC) represents above 3 % of all cancers, with the highest incidence occurring in Western countries. At diagnosis, above 25 % of patients with RCC present an advanced disease, including locally invasive or metastatic cancer. The mean survival time of patient with metastatic RCC is approximately 13 months. The most common metastatic RCC sites are the lung and bone (up to 60 % and 40 % of patients with metastases). However, unusual sites of metastasis are characteristics of RCC and any organ site can be involved, including the thyroid, pancreas, skeletal muscle and skin.”
    Are gastric metastases of renal cell carcinoma really rare? A case report and systematic review of the literature
    Thomas Prudhomme et al.
    International Journal of Surgery Case Reports, Volume 82,2021
  • "At RCC gastric metastasis diagnosis, 73 % of the patients presented multiple metastatic sites, mainly lungs and bones. The median patients age (IQR) was 66.0 (60.0–69.0) years, of whom 74 % were men. The median time (IQR) between the diagnosis of RCC and metachronous gastric metastasis was 5.0 (2.0–9.5) years. 3 patients presented RCC with synchronous gastric metastasis. 35 % of the patients had a surgical treatment, 16 % an endoscopic treatment, 23 % a systemic therapy and 26 % a palliative treatment. Endoscopic treatment was mucosal and submucosal resection without positive surgical margins. Median patient survival (IQR), after treatment, was 6 months.”
    Are gastric metastases of renal cell carcinoma really rare? A case report and systematic review of the literature
    Thomas Prudhomme et al.
    International Journal of Surgery Case Reports, Volume 82,2021
  • "Renal cell carcinoma is the most common solid lesion within the kidney and accounts approximately 90 % of all kidney malignancies. It comprises different RCC subtypes with specific histopathological characteristics. Clear cell RCC is the most common histopathological entities of RCC and clear cell RCC has worse prognosis compared to other histopathological entities, even after stratification for stage and grade. Indeed, clear cell RCC has an abundant blood supply and can metastasize to several organs. Metastasis routes include hematogenous, lymphogenous, renal capsule, renal pelvis and ureteric routes, which explains the wide variety of organs that can be RCC metastatic sites.”
    Are gastric metastases of renal cell carcinoma really rare? A case report and systematic review of the literature
    Thomas Prudhomme et al.
    International Journal of Surgery Case Reports, Volume 82,2021
  • “Between January 2007 and December 2019, 11 out of 660 (1.6%) mRCC patients had metastases of the gastrointestinal tract. The median age was 62 years. Of the 11 patients, 81.8% experienced digestive bleeding or anemia. Only 2 patients were asymptomatic. The metastases were mainly duodenal (50%) and gastric (41.6%). The median time from cancer diagnosis and from metastatic disease to gastrointestinal metastasis was 4.3 years (3 months−19.2 years) and 2.25 years (0 days−10.2 years), respectively.”
    Gastrointestinal Metastases From Primary Renal Cell Cancer: A Single Center Review  
    Rony Maelle et al.
    Front. Oncol. 11:644301. doi: 10.3389/fonc.2021.644301 
  • “DM of kidney cancer, whether gastric, duodenal or jejunal, is rare. In autoptic studies, the stomach has been reported as a metastatic site in 0.2–0.7% of cases, regardless of the primary site. The prevalence of RCC gastric metastases in the Pollheimer study was 0.2% over 22 years. Our study is, to the best of our knowledge, the largest monocentric study providing the prevalence of RCC metastasis throughout the digestive tract.”
    Gastrointestinal Metastases From Primary Renal Cell Cancer: A Single Center Review  
    Rony Maelle et al.
    Front. Oncol. 11:644301. doi: 10.3389/fonc.2021.644301 
  • “The interval between diagnosis of the primary tumor and gastric metastasis depends on the primary tumor. For lung cancer and melanoma, metastasis is diagnosed an average of 2 years after the initial diagnosis. For RCC, the average interval is 7 years (0–24 years) . In the Pollheimer et al. study of 17 patients, the mean interval was 6.5 years with a median of 4.7 years (0.1–20 years) , and the same timelines were found in Kim et al.’s study of 36 patients.”
    Gastrointestinal Metastases From Primary Renal Cell Cancer: A Single Center Review  
    Rony Maelle et al.
    Front. Oncol. 11:644301. doi: 10.3389/fonc.2021.644301 
  • "DM in patients with RCC appears to be a late event in the course of the disease. In the majority of cases, they are discovered upon digestive bleeding, but sometimes only anemia is present. It is important to be aware that unexplained anemia or persistent digestive symptoms should be explored by endoscopy. However, due to the evolved molecular targeted and new immunotherapies, the survival period of the patients with mRCC was prolonged. Therefore, at the routine follow-up CT scan, we must be aware that formerly rare metastatic sites including digestive wall may increase.”
    Gastrointestinal Metastases From Primary Renal Cell Cancer: A Single Center Review  
    Rony Maelle et al.
    Front. Oncol. 11:644301. doi: 10.3389/fonc.2021.644301 
  • “RCC is the second most common renal malignancy of childhood after Wilms tumor; however, it is more common than Wilms tumor in individuals who are in their 2nd decade of life. Overall, the annual incidence of pediatric RCC is approximately four cases per one million children, 30 times lower than the annual incidence of Wilms tumor.There is an equal gender distribution. Pediatric RCC is different from adult RCC. In adults, the most common RCC tumor types are clear cell carcinoma (80%–85%), papillary carcinoma (10%–15%), and chromophobe carcinoma (5%). In contrast, the most frequent types of RCC in children are translocation carcinoma (20%– 47%), papillary carcinoma (17%–30%), and medullary carcinoma (11%), with chromophobe and clear cell RCCs occurring quite rarely .”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • TEACHING POINTS  
    * RCC is the second most common renal malignancy of child- hood after Wilms tumor; however, it is more common than Wilms tumor in individuals who are in their 2nd decade of life.  
    * At imaging, translocation RCCs generally have a heteroge- neous appearance owing to solid and cystic components with hemorrhage, necrosis, and calcifications.  
    * Renal medullary carcinoma is an aggressive tumor that affects almost exclusively older children and young adults with the  sickle cell trait or heterozygous sickle cell disease.  
    * Angiomyolipoma is a neoplasm of mixed cellular composition and is now considered part of the family of perivascular epi-  thelioid cell tumors.  
    * Metanephric tumors comprise a spectrum of rare differenti- ated epithelial and stromal tumors that are derived from metanephric blastema and are histogenetically related to Wilms tumor.  
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "First classified as a genetically distinct subtype of RCC by the World Health Organization, translocation RCC accounts for one-third to nearly one-half of all pediatric RCCs.There is a slight female predominance, with a male-to- female ratio of 1.0:1.4. Although patients may have symptoms such as flank pain, a mass, or gross hematuria, these tumors are often found incidentally.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "Xp11.2 translocation involves gene fusion and subsequent overexpression of transcription factor E3 (TFE3). Multiple variations of the Xp11.2 chromosome translocation have been reported, and all of them cause overexpression of the TFE3 gene.While the origin of these translo- cations is poorly understood, a known risk factor is a history of cytotoxic chemotherapy during childhood. In their review of 39 genetically confirmed cases, Argani et al found that 15% of the cases involved treatment with cytotoxic chemotherapy.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 

  • Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "Renal medullary carcinoma is an aggressive tumor that affects almost exclusively older children and young adults with the sickle cell trait or hetero- zygous sickle cell disease. The age range of affected individuals is 5–39 years (mean age, 14.8 years). Among persons younger than 25 years, males are affected three times more often than are females, but there is an equal distribution between the sexes after age 25 years.The most common features at presentation are gross hematuria and flank pain; however, hematuria is not uncommon in individuals who have the sickle trait without tumor. An abdominal mass, weight loss, and fever are less common.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • “These tumors arise from the terminal collecting ducts or papillary epithelium, where a chronic hypoxic sickle cell trait environment causes epithelial cell proliferation. There is a predilection for the right kidney. At gross specimen inspection, the tumor is centered in the renal medulla, with an infiltrative growth pattern and extension into the renal collecting system. In addition, satellite nodules are typically seen in the renal cortex and peripelvic soft tissues.Tumor necrosis and hemorrhage are usually identified, and calcifications are rare, weight loss, and fever are less common.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "The differential diagnosis for renal medullary carcinoma includes renal lymphoma, which also may grow in an infiltrative pattern. Lymphoma is usually distinguished by associated widespread lymphadenopathy and involvement of other organs. However, renal medullary carcinoma also can manifest with extensive disease, so patient age and history of the sickle cell trait are help-  ful clues to the diagnosis. Rhabdoid tumor and mesoblastic nephroma are additional medullary tumors with infiltrative growth patterns; however, both of these neoplasms occur in much younger patients. Infection may have an infiltrative appearance, with extension into the perinephric fat and enlargement of regional lymph nodes, mimicking the appearance of medullary carcinoma. Clinical and laboratory findings help to distinguish infection from tumor.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "Metanephric adenoma is the most com- mon of these tumors and occurs most often in adult women with a mean age of 41 years (age range, 14 months to 83 years). There is a female predominance, with a female-to-male ratio of 2.6:1.0. Metanephric stromal tumors occur most commonly in young children witha mean age of 2 years (age range, 5 months to 15 years). Metanephric adenofibroma most commonly affects children and young adults. The mean age of affected persons is 82.2 months (age range, 5 months to 36 years). Presenting signs include pain, hematuria, hyper- tension, and a palpable mass, but these tumors frequently are found incidentally. Davis et al found an association between metanephric adenoma and polycythemia in 12% of cases.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • "Lymphomas may affect the kidneys as solitary masses; however, they are more often multiple bilateral expansile renal masses or nodules. Less commonly, diffuse infiltration is observed, and rarely, the tumor involves only the perinephric tissues. At pathologic analysis, large masses demonstrate central hemorrhage and necrosis. At histologic examination, Burkitt lymphoma is composed of uniform medium basophilic cells interspersed with clear histiocytes that contain debris from apoptotic cells, conferring a “starry sky” appearance. Mitoses are frequent. Tumor cells express mature B-cell markers (ie, CD19, CD20, CD22, and CD79a) and a Ki-67 pro- liferation index of nearly 100%. The imaging appearances of lymphoma vary according to the type of tumor growth.The most common appearance is that of multiple round masses or nodules.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • “1At CT, the masses are hypoattenuating and enhance less intensely compared with the adjacent parenchyma. Lymphomatous lesions are more conspicuous on MR images than on CT images. Diffuse infiltration, usually of both kidneys, is the typical appearance of leukemic infiltration at imaging and may also be seen with lymphoma. The kidneys are enlarged but remain reniform, with decreased corticomedullary differentiation; these findings are often quite subtle.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 
  • “At gross specimen inspection, the tumor appears solid, with areas of hemorrhage, necrosis, and cyst formation. Histologically, the tumor is composed of monomorphic spindle cells arranged in intersecting fascicles or solid sheets. Mitotic activity is typically seen. The tumor also contains cysts lined by eosinophilic cells with apically oriented nuclei.This lining is known as a hobnailed epithelium.The cysts probably represent entrapped tubules and may be quite dilated. Ninety percent of these tumors have the characteristic translocation t(X;18)(p11.2;q11).  Imaging studies reveal a well-circumscribed solid mass with prominent fluid-attenuating areas that represent necrosis, old hemorrhage, or cysts. The cysts may predominate. The septa, cyst walls, and solid components enhance. Subcapsular hemorrhage or renal vein invasion may be seen, but lymphadenopathy is absent.”
    Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade  
    Ellen M. Chung et al.
    RadioGraphics 2017; 37:1538–1558 

  • Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “Most conventional RCC subtypes (ie, clear cell, papillary, and chromophobe) demonstrate an expansile growth pattern, appearing as focal well-circumscribed masses, with only a small percentage manifesting as atypical infiltrative masses. In addition to the atypical infiltrative growth of conventional RCCs, infiltrative growth often manifests in any RCC subtype with sarcomatoid or rhabdoid features.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “Renal medullary carcinoma is a rare and aggressive tumor that arises from the renal papilla or calyceal epithelium of the renal medulla. It accounts for only 1%–2% of RCCs and is found almost exclusively in individuals with the sickle cell trait. The pathogenesis is hypothesized to be chronic hypoxia related to the hemoglobinopathy, which leads to a proliferation of the terminal collecting ducts and papillary epithelium that triggers a neoplastic transformation. Interestingly, there is no association between renal medullary carcinoma and sickle cell disease.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “A systematic review of all reported cases of renal medullary carcinoma through 2013 (47 articles, 165 cases) confirmed the presence of multiple characteristic features: Sixty-seven percent of affected patients presented with hematuria and pain, 71% were male, 93% were African American, and 98% had sickle cell trait. The median age of affected patients was 21 years. The right kidney is preferentially affected in more than 75% of cases.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “Renal medullary carcinoma is one of the most aggressive renal malignancies, with dismal clinical outcomes and a median survival of 13–17 months. The average tumor size at presentation is 6 cm, and most patients have metastatic disease at the time of presentation, most frequently involving the regional lymph nodes, lungs, liver, adrenal glands, or contralateral kidney.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “At imaging, renal medullary carcinoma appears as a large ill-defined, poorly circumscribed tumor that is predominantly centered in the renal medulla, with extension into the renal sinus. Most tumors exhibit growth into the renal cortex, with perinephric and peripelvic soft tissue at the time of diagnosis. The medullary origin can be difficult to appreciate in cases of large masses. The tumor causes expansion of the affected kidney while maintaining its reniform shape. Hemorrhage and geographic necrosis are typically present, giving the tumor a heterogeneous appearance on CT images and sometimes producing a signal void on T2-weighted MR images due to susceptibility artifact related to the blood products.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “SCC is the second most common malignancy of the renal pelvic urothelium after UCC, but this type of carcinoma is relatively rare, constituting 8%–15% of renal pelvic tumors and less than 1% of all renal malignancies. There is an increased prevalence of SCC among patients with renal calculi and in countries where the parasitic infection schistosomiasis is endemic, as chronic urothelial infection and irritation lead to squamous metaplasia. Most patients are aged 50–60 years at diagnosis and present with an insidious onset of hematuria and flank pain. Fever and additional constitutional symptoms such as anorexia, weight loss, and fatigue may also be present. Renal pelvic SCC is a highly aggressive tumor that primarily exhibits an infiltrative pattern of growth..”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “Because the kidneys lack any substantial lymphoid tissue, lymphoma rarely involves the kidneys as a primary process without evidence of disease elsewhere. Most cases of renal lymphoma occur in the presence of widespread nodal or extranodal disease, with secondary spread to the kidney via hematogenous dissemination or contiguous extension of retroperitoneal disease. After the hematopoietic and reticuloendothelial organs, the kidneys are the next most common site affected by extranodal spread of lymphoma. Lymphomatous spread to the kidneys is usually clinically silent and occurs late in the course of the disease, after the diagnosis has been established.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “In autopsy series, the incidence of metastasis to the kidney has ranged from 7% to 13%. With advances in oncologic care leading to prolonged patient survival and with increasing use of surveillance cross-sectional imaging, renal metastases are now frequently detected in living patients, whereas historically they were typically identified postmortem. However, the prevalence of kidney metastasis detected at imaging in living patients has been observed to be closer to 1%. Lung cancer is the most common primary malignancy to metastasize to the kidneys, accounting for up to 44% of metastases, followed by colorectal, stomach, and breast malignancies. Metastases from other primary tumors are much less common. The diagnosis of metastasis to the kidney in patients without evidence of a widespread nonrenal malignancy is rare; a focal renal mass is more likely to represent a primary renal tumor.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • “Renal metastases have a wide spectrum of imaging characteristics that largely depend on the site of the primary tumor. Most metastases form multifocal small round discrete masses, although infiltrative growth with irregular margins has been reported in up to 28% of cases. Multifocal bilateral masses are more common than unilateral solitary and bilateral solitary masses. They are often homogeneous and hypoenhancing relative to the normal renal parenchyma on contrast-enhanced images, but heterogeneous features, including areas of cystic necrosis, hemorrhage, calcification, and hypervascularity, have been described. Invasion of the renal vein and inferior vena cava is uncommon. Larger masses often infiltrate the perinephric space; this occurrence is associated with primary lung and melanoma tumors. Large and exophytic renal metastases, usually an uncommon appearance for metastases, are characteristic of primary colon cancer.”
    Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
    Sweet DE et al.
    RadioGraphics 2021; 41:0000–0000
  • Infiltrative Mimics of Malignancy
    - Acute Bacterial Pyelonephritis
    - Xanthogranulomatous Pyelonephritis
    - Renal Infarct
    - IgG4–related Kidney Disease
  • Presacral Masses in Extramedullary Hematopoeisis: Differential Dx
    - lymphoma
    - extra-adrenal myelolipoma
    - radiation therapy related changes
    - Sarcomas
    - Chordoma
    - chronic osteomyelitis
  • Oncocytic Neoplasms: Facts
    - Fairly common diagnosis (9% of SRMs)
    - No technique to differentiate oncocytic RCC from oncocytoma with 100% reliability from imaging or biopsy
    - Hybrid tumors: oncocytoma and RCC coexist in one tumor in up to 17% of “oncocytomas”
  • Renal oncocytoma is a benign (noncancerous) growth of the kidney. They generally do not cause any signs or symptoms and are often discovered incidentally (by chance) while a person is undergoing diagnostic imaging for other conditions. Some people with renal oncocytoma will have abdominal or flank pain; blood in the urine; and/or an abdominal mass. Although these tumors can occur in people of all ages, they most commonly develop in men who are over age 50.
    NIH-Genetic and Rare Disease Information Center
  • The exact underlying cause of most isolated (single tumor affecting one kidney) renal oncocytomas is unknown; however, multiple and bilateral (affecting both kidneys) renal oncocytomas sometimes occur in people with certain genetic syndromes such as tuberous sclerosis complex and Birt-Hogg-Dube syndrome. Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma. Most affected people are, therefore, treated with surgery which allows for confirmation of the diagnosis.
    NIH-Genetic and Rare Disease Information Center
  • “Metastases to the kidney are a rare entity. Survival appears to be longer in patients who are candidates for and are treated with surgery. Surgical intervention in carefully selected patients with oligometastatic disease and good performance status should be considered. A multidisciplinary approach with input from urologists, oncologists, radiologists and pathologists is needed to achieve the optimum outcomes for this specific patient population.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “We found that the most common primary tumours in descending order were lung, colorectal, head and neck and breast/soft tissue/thyroid. This is consistent with historical reports noting the lung as the most prevalent source of metastases, followed by a combination of colorectal, stomach and breast malignancies .Over half of the patients in our cohort were asymptomatic.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “In conclusion, metastases to the kidney are still a rare entity. These are typically bronchogenic in nature, solitary and asymptomatic. Diagnostic concordance between radiologist and clinician was lower than expected. Thus, a high index of suspicion and a careful review of the scans by all involved physicians is necessary in the patient with a non-renal malignancy who presents with a suspicious renal mass on imaging. Since renal metastases appear early in the metastatic process and survival appears to be longer in patients treated with surgery, surgical intervention in carefully selected patients with oligometastatic disease and good performance status should be considered.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “Renal involvement in lymphoma commonly occurs in the presence of widespread nodal or extranodal lymphoma and is classified as secondary renal lymphoma (SRL). However, lymphoma may rarely involve the kidneys alone without evidence of disease elsewhere; then, it is termed “primary renal lymphoma” (PRL).”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “Although the diagnosis of renal lymphoma can be challenging, an awareness of the spectrum of imaging findings can help to differentiate lymphoma from other renal malignancies such as renal cell carcinoma (RCC) and can lead to appropriate recommendations for biopsy. An accurate diagnosis is critical because renal lymphoma is treated by chemotherapy whereas RCC is typically managed by surgery or ablation.”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • CT Appearance of Renal Lymphoma
    - Unilateral or bilateral
    - Solitary or multiple masses
    - Nephromegaly without focal mass
    - Renal Lymphoma is typically Hypovascular
    - Infiltration of the kidney and the perirenal space
    - Adenopathy is often bulky
  • “Renal lymphoma usually occurs in the setting of widespread non-Hodgkin lymphoma, typically B-cell type intermediate- and high-grade tumors or American Burkitt lymphoma. In more than one-half of cases, renal or perirenal spread is detected at initial presentation. Involvement by Hodgkin disease is much less common, being seen in less than 1% of patients at presentation.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation. 
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • "Renal lymphoma has a wide variety of manifestations, including multiple lesions, a solitary lesion, direct extension from retroperitoneal adenopathy, preferential involvement of the perinephric space, and diffuse infiltration of one or both kidneys. The renal sinus and collecting system are less frequently affected, except for obstruction caused by retroperitoneal adenopathy. In a large autopsy series of 696 patients with lymphoma, Richmond et al observed multiple renal masses in 61% of cases. A solitary renal nodule and direct invasion from retroperitoneal adenopathy were equally common, being found in 11 kidneys each.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation.
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • Patterns of Renal Lymphoma on CT
    - Multiple masses (unilateral or bilateral)
    - Solitary mass
    - Direct Extension from Retroperitoneal Adenopathy
    - Perinephric Disease
    - Nephromegaly
  • “Renal involvement in lymphoma commonly occurs in the presence of widespread nodal or extranodal lymphoma and is classified as secondary renal lymphoma (SRL). However, lymphoma may rarely involve the kidneys alone without evidence of disease elsewhere; then, it is termed “primary renal lymphoma” (PRL).”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “Although the diagnosis of renal lymphoma can be challenging, an awareness of the spectrum of imaging findings can help to differentiate lymphoma from other renal malignancies such as renal cell carcinoma (RCC) and can lead to appropriate recommendations for biopsy. An accurate diagnosis is critical because renal lymphoma is treated by chemotherapy whereas RCC is typically managed by surgery or ablation.”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “In contrast to PRL, SRL commonly occurs in patients with widespread disease. Although autopsy studies report an incidence as high as 30–60%, the imaging manifestations of SRL occur in only 1–8%. This discrepancy between autopsy and imaging studies may be explained by a high incidence of clinically silent cases that are diagnosed only after microscopic examination of the kidneys. SRL occurs from either direct or hematogenous spread from disseminated disease.”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “Although any subtype of lymphoma can involve the kidneys, renal lymphoma (both PRL and SRL) is most commonly seen in patients with non-Hodgkin lymphoma, usually the B-cell type or Burkitt lymphoma. Rarely, the kidneys may be involved in Hodgkin lymphoma. Immunocompromised status secondary to organ transplantation and HIV infection may predispose patients to renal lymphoma .”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “Renal lymphomas are associated with various imaging appearances on CT and MRI. The disease may be unilateral or bilateral and may present as focal masses (solitary or multiple) or diffuse infiltrative lesions or may manifest as enlarged kidneys without focal lesions. Unlike RCC, renal lymphoma is typically hypovascular and does not invade the vessels. Early diagnosis and proper management result in a favorable outcome.”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • CT Appearance of Renal Lymphoma
    - Unilateral or bilateral
    - Solitary or multiple masses
    - Nephromegaly without focal mass
    - Renal Lymphoma is typically Hypovascular
    - Infiltration of the kidney and the perirenal space
    - Adenopathy is often bulky
  • “Renal lymphoma usually occurs in the setting of widespread non-Hodgkin lymphoma, typically B-cell type intermediate- and high-grade tumors or American Burkitt lymphoma. In more than one-half of cases, renal or perirenal spread is detected at initial presentation. Involvement by Hodgkin disease is much less common, being seen in less than 1% of patients at presentation.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation. 
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • "Renal lymphoma has a wide variety of manifestations, including multiple lesions, a solitary lesion, direct extension from retroperitoneal adenopathy, preferential involvement of the perinephric space, and diffuse infiltration of one or both kidneys. The renal sinus and collecting system are less frequently affected, except for obstruction caused by retroperitoneal adenopathy. In a large autopsy series of 696 patients with lymphoma, Richmond et al observed multiple renal masses in 61% of cases. A solitary renal nodule and direct invasion from retroperitoneal adenopathy were equally common, being found in 11 kidneys each.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation.
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • Patterns of Renal Lymphoma on CT1
    - Multiple masses (unilateral or bilateral)
    - Solitary mass
    - Direct Extension from Retroperitoneal Adenopathy
    - Perinephric Disease
    - Nephromegaly
  • Perinephric Masses on CT: Differential Diagnosis
    - Lymphoma
    - Metastases (especially melanoma)
    - Myeloma
    - Urinomas
    - Hemmorrhage
    - Infection
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Erdheim Chester disease
  • Renal oncocytoma is a benign (noncancerous) growth of the kidney. They generally do not cause any signs or symptoms and are often discovered incidentally (by chance) while a person is undergoing diagnostic imaging for other conditions. Some people with renal oncocytoma will have abdominal or flank pain; blood in the urine; and/or an abdominal mass. Although these tumors can occur in people of all ages, they most commonly develop in men who are over age 50. The exact underlying cause of most isolated (single tumor affecting one kidney) renal oncocytomas is unknown; however, multiple and bilateral (affecting both kidneys) renal oncocytomas sometimes occur in people with certain genetic syndromes such as tuberous sclerosis complex and Birt-Hogg-Dube syndrome.Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma. Most affected people are, therefore, treated with surgery which allows for confirmation of the diagnosis.
    NIH-Genetic and Rare Disease Information Center
  • Renal oncocytoma is a benign (noncancerous) growth of the kidney. They generally do not cause any signs or symptoms and are often discovered incidentally (by chance) while a person is undergoing diagnostic imaging for other conditions. Some people with renal oncocytoma will have abdominal or flank pain; blood in the urine; and/or an abdominal mass. Although these tumors can occur in people of all ages, they most commonly develop in men who are over age 50.
    NIH-Genetic and Rare Disease Information Center
  • The exact underlying cause of most isolated (single tumor affecting one kidney) renal oncocytomas is unknown; however, multiple and bilateral (affecting both kidneys) renal oncocytomas sometimes occur in people with certain genetic syndromes such as tuberous sclerosis complex and Birt-Hogg-Dube syndrome.Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma. Most affected people are, therefore, treated with surgery which allows for confirmation of the diagnosis.
    NIH-Genetic and Rare Disease Information Center
  • “Enhanced renal masses less than 4 cm in size are known as small renal masses (SRMs), and their growth rate (GR) and the possibility of developing metastasis are extremely low. Delayed intervention of SRMs by closed and routine imaging follow- up known as active surveillance (AS) is now an option according to urological guidelines. Radiologists have a key position in AS management of SRMs even unifocal and multifocal (sporadic or associated with genetic syndromes) and also in the follow-up of complex renal cysts by Bosniak cyst classification system. Radiologists play a key role in the AS of both unifocal and multifocal (sporadic or associated with genetic syndromes)”
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • • Small renal masses are contrast-enhancing renal tumors less than or equal to 4 cm.
    • Active surveillance is defined as initial management including the monitoring of renal tumor size.
    • The follow-up protocol most commonly used in- cludes enhanced abdominopelvic CT scanning.
    • Progression is defined as a linear growth rate greater than 0.5 cm per year, diameter greater than 4 cm, or metastasis.
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • “Small renal masses are the ones most indicated to be included in AS. Since SRMs tend to be indolent, with slow growth rates (1–3 mm per year), and are associated with a relatively low risk of metastasis (1–3%). AS is the most ad- equate treatment approach. Large renal masses (LRM), which are defined as solid localized renal masses greater than 4 cm in size usually corresponding to T1b and T2 RCC, can also be followed by AS, although the more rapid growth (4–8 mm per year) and higher risk of M1 metastasis (4–6%) require that this approach be made with caution.”
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • According to the 2017 AUA guidelines:
    – AS is an option for initial management in patients with renal masses suspicious for cancer, especially those smaller than 2 cm.
    – AS or expectant management should be a priority when the anticipated risk of intervention or competing risks of death outweigh the potential oncologic benefits of active treatment.
    – When the results of a risk-versus-benefit analysis of the treatment are equivocal and the patient elects to undergo AS.
    – When the oncologic benefits of intervention outweigh the risks of treatment and competing risks of death, physicians should recommend active treatment. In this setting AS with potential for delayed intervention may be pursued only if the patient understands and is willing to accept the associated oncologic risk.
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • The ASCO guidelines define the indications of AS as follows:
    –  Absolute indications: high risk for anesthesia and intervention or life expectancy less than 5 years –  Relative indications: significant risk of end-stage renal disease (ESRD) if treated, SRM less than 1 cm, or life expectancy less than 10 years
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • Renal masses: contraindications for active surveillance AS should not be carried out in the following: –  Benign renal masses reliably diagnosed by imaging or biopsy
    –  Renal masses with irregular borders
    –  Non-localized renal tumors (i.e., locally, lymphatically, or hematogenously disseminated)
    –  When the oncologic benefits of intervention outweigh the risks of treatment and competing risks of death
    –  When the patient refuses to be included in AS
    Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63

  • Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63

  • Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63

  • Active surveillance of small renal masses
    Carmen Sebastià et al.
    Insights into Imaging (2020) 11:63
  • Renal Medullary Carcinoma: Facts
    - Highly aggressive renal neoplasm that has association with sickle cell trait or rarely hemoglobin SC disease (unknown mechanism).
    - Some considered this be a variant of collecting duct carcinoma.
    - Usually encountered in young patients, male > female (2:1), mostly African-American and with sickle cell hemoglobinopathies.
  • Renal Medullary Carcinoma: Facts
    - Patients with RMC tend to be young with a median age of 19-22 years.
    - Patients are almost always of black race (although RMC has been reported in Hispanics/Brazilians and a few Caucasians).5 Nearly all RMC patients have sickle cell trait or, rarely, sickle cell disease.
  • Renal Medullary Carcinoma: Facts
    - The right kidney is the affected kidney in more than 75% of cases. Metastasis at presentation is extremely common. The most common sites of metastases are the regional lymph nodes, adrenal glands, lung, liver, inferior vena cava, and peritoneum
    - RMC is a highly aggressive cancer with an extremely poor prognosis. Mean survival time of less than 1 year is seen in most cases.
  • “Renal medullary carcinoma (RMC) is an aggressive form of non–clear cell kidney cancer that typically affects young adults and is almost exclusively associated with sickle cell trait. Typical RMC patients tend to be young black males (2:1 male to female predominance) with sickle cell trait who present with pain and hematuria and are found to have metastatic disease at diagnosis. Prognosis is extremely poor, with a mean survival of less than a year in most cases.”
    Renal Medullary Carcinoma: A Case Report and Brief Review of the Literature
    Aditya Shetty, Marc R. Matrana, Ochsner J.
    2014 Summer; 14(2): 270–275
  • "One type of non–clear cell RCC that has been more recently recognized is renal medullary carcinoma (RMC). RMC is an aggressive form of kidney cancer first described by Davis et al in 1995.The disease almost always affects young patients with sickle cell trait and has been described as the seventh sickle cell nephropathy (the other sickle cell nephropathies are gross hematuria, papillary necrosis, nephrotic syndrome, renal infarction, inability to concentrate urine, and pyelonephritis).”
    Renal Medullary Carcinoma: A Case Report and Brief Review of the Literature
    Aditya Shetty, Marc R. Matrana, Ochsner J.
    2014 Summer; 14(2): 270–275
  • The tumors in the current study presented a mean diameter of 7.48±3.25 cm, and were observed to be solitary and heterogeneous with necrotic components. The majority of the tumors did not contain calcifications (5/6); displayed an ill-defined margin (4/6); were centered in the medulla; extended into the renal pelvis or peripelvic tissues (6/6); and did not exhibit a fibrous capsule. Localized caliectasis was observed in 3 of the 6 cases. The attenuation of the solid region of the RMC on unenhanced CT was equal to that of the renal cortex or medulla (42.3±2.7 vs. 40.7±3.6 and 41.2±3.9 Hounsfield units, respectively; P>0.05) while, on enhanced CT, the enhancement of the tumor was lower than that of the normal renal cortex and medulla during all phases (cortical phase, 52.6±4.8 vs. l99.5±9.7 and 72.7±6.4; medullary phase, 58.6±5.7 vs. 184.6±10.8 and 93.5±7.8; delayed phase, 56.8±6.1 vs. 175.7±8.5 and 96.5±7.9, respectively; P<0.05). 
  • "In conclusion, RMC tends to be an infiltrative, ill-defined heterogeneous mass with intratumoral necrosis, which arises from the renal medulla, and displays lower enhancement than the renal cortex and medulla during all phases on enhanced CT. Despite its rarity in adults, RMC should be included in a differential diagnosis when CT imaging reveals these features."
    Clinical and computed tomography imaging features of renal medullary carcinoma: A report of six cases.
    Shi Z1, Zhuang Q2, You R1, Li Y1, Li J1, Cao D
    Oncol Lett. 2016 Jan;11(1):261-266. Epub 2015 Nov 9
  • “Primary renal lymphoma without systemic extension is a rare clinical occurrence and it accounts for less than 1% of extranodal lymphomas. As the renal parenchyma does not normally contain lymphoid tissue, the development of primary renal lymphomas is thought to originate from lymphatic-rich renal capsule or perirenal fat with subsequent extension into the renal parenchyma. Secondary renal lymphomas may commonly occur in patients with advanced stage disease. Autopsy series of patients with lymphoma showed renal involvement in 30%–60% of the cases. Renal lymphomas are usually B cell non-Hodgkin type lymphomas. Secondary lymphomatous involvement of the kidneys is usually clinically silent, however, in a small percentage of patients flank pain, hematuria, and rarely renal failure may be observed.”
    Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
    Gumeler E et al.
    Abdom Radiol (NY). 2018 Sep;43(9):2400-2411
  • “Renal involvement typically presents as solid solitary or multiple lesions within the renal parenchyma. Perirenal or diffuse parenchymal involvement may also be seen some patients. Isolated renal sinus involvement is rare and peripelvic involvement occurs secondary to tumoral extension from the conglomerated retroperitoneal lymph nodes. Ureteral obstruction may be frequently observed in patients with periureteral extension. Renal vascular occlusion or thrombosis is rare despite extensive encasement of these structures, owing to the soft and pliable nature of the lymphoma .”
    Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
    Gumeler E et al.
    Abdom Radiol (NY). 2018 Sep;43(9):2400-2411
  • “CT demonstrates low attenuated lymphomatous infiltration along renal sinus and ureteral wall while this infiltration typically manifests as hypointense on both T1W and T2W images on MRI scans. This infiltrative growth pattern is reminiscent of transitional cell carcinomas (TCCs) and other inflammatory processes such as XGP. Based on these similarities, both TCC and XGP should be considered in the differential diagnosis. Mild and homogeneous post-contrast enhancement may be a helpful imaging hint to differentiate peripelvic and periureteral lymphoma from these disorders.”
    Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
    Gumeler E et al.
    Abdom Radiol (NY). 2018 Sep;43(9):2400-2411
  • “Papillary RCCs are rarely both subjectively homogeneous and less than 20 HU at unenhanced CT and less than 30 HU at portal venous or nephrographic phase CT.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “Mean lesion size was 2.8 cm (range, 1.2–11.0 cm). The attenuation range for each CT phase was as follows: unenhanced, 14.7–50.7 HU; corticomedullary, 32.2–99.5 HU; portal venous, 40.8–95.1 HU; nephrographic, 17.9–90.8 HU; and excretory, 18.0–73.0 HU. Two of 114 (1.8%; 95% CI, 0.2–6.5%) RCCs were homogeneous and less than 30 HU on the portal venous or nephrographic phase. One of these RCCs was a solid hypoenhancing mass, and the other was a homogeneous cystic RCC. Of the cases with an unenhanced phase, three of 107 (2.8%; 95% CI, 0.6–8.8%) were both homogeneous and were less than 20 HU in attenuation.
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “Two of 114 (1.8%; 95% CI, 0.2–6.5%) RCCs were homogeneous and less than 30 HU on the portal venous or nephrographic phase. One of these RCCs was a solid hypoenhancing mass, and the other was a homogeneous cystic RCC. Of the cases with an unenhanced phase, three of 107 (2.8%; 95% CI, 0.6–8.8%) were both homogeneous and were less than 20 HU in attenuation.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • The 20-HU threshold for follow-up of incidentally detected renal masses at contrast-enhanced CT has recently been revisited. Most RCCs are heterogeneous, and among the RCCs that are homogeneous, most will have attenuation values above 40 HU on contrast-enhanced images.
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “An incidental renal mass is considered to be a benign cyst if it is both homogeneous and less than 20 HU and is considered indeterminate if it measures above 20 HU on either unenhanced or contrast-enhanced CT.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “The second important finding of our study is that papillary RCC can both be homogeneous and measure less than 20 HU on unenhanced CT in a small percentage of cases (≈ 3% in this study). Schieda et al. found eight of 96 RCCs to have attenuation values less than 20 HU at unenhanced CT. The eight RCCs with attenuation less than 20 HU were inhomogeneous, and all were clear cell RCCs.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “We suggest that the optimal threshold attenuation to trigger further imaging of homogeneous renal masses may be higher than 20 HU for portal venous phase CT. Factors such as lesion size, lesion location, and patient factors such as age and co-morbidities are important to consider in making the decision to follow a lesion.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “In conclusion, papillary RCCs are rarely (0.2–6.5%) both subjectively homogeneous and low attenuation, defined as measuring less than 20 HU at unenhanced CT or less than 30 HU at portal venous or nephrographic phase CT.”
    Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT
    Corwin MT et al.
    AJR 2018; 211:1259–1263
  • “In clear cell RCCs, the gross appearance of intratumoral vascularity at MDCT was significantly associated with CAIX score, a prognostically significant molecular marker. Current assessment of CAIX score requires pathologic tissue sampling and immuno- histochemical analysis. A noninvasive imaging biomarker that may help predict CAIX score may be of great clinical value.”
    Association of the Gross Appearance of Intratumoral Vascularity at MDCT With the Carbonic Anhydrase IX Score in Clear Cell Renal Cell Carcinoma
    Young JR et al.
    AJR 2018; 211:1254–1258
  • “The most common histologic subtype of RCC within the Vancouver and the recently modified World Health Organization classification is clear cell RCC, accounting for 70–80% of RCCs. Clear cell RCC is associated with the worst prognosis, having a 5-year survival rate of 44–69% and accounting for 94% of cases of metastatic RCC.”
    Association of the Gross Appearance of Intratumoral Vascularity at MDCT With the Carbonic Anhydrase IX Score in Clear Cell Renal Cell Carcinoma
    Young JR et al.
    AJR 2018; 211:1254–1258
  • “Several studies have identified carbonic anhydrase IX (CAIX) as a prognostically significant molecular biomarker of clear cell RCC. Chamie et al. developed the CAIX score, which is calculated by multiplying the positive staining percentage by the staining intensity (on a scale of 1–3), resulting in a score ranging from 0 to 300.”
    Association of the Gross Appearance of Intratumoral Vascularity at MDCT With the Carbonic Anhydrase IX Score in Clear Cell Renal Cell Carcinoma
    Young JR et al.
    AJR 2018; 211:1254–1258
  • “Multicentric renal cysts and clear cell RCCs
may manifest in more than two-thirds of VHL cases. Even grossly normal renal parenchyma may demonstrate hundreds
of microscopic renal cysts and tumors. The cystic lesions may be a combination of simple benign cysts, complex atypical cysts with epithelial hyperplasia/cytologic atypia, or cystic RCCs.The number and size of the cysts in VHL have not been shown to be associated with malignant potential. Patients may be asymptomatic despite the manifestation of a large number of cysts.”


    Tumors in von Hippel–Lindau Syndrome: From Head to Toe—Comprehensive State-of-the-Art Review 
Ganeshan D et al.
 RadioGraphics 2018 (in press)
  • “VHL is characterized by the development of a clear cell RCC histologic subtype. The prevalence of RCC in VHL varies from 25% to 45%, with the frequency increasing with age. VHL-related RCCs tend to develop at a much younger age compared with that of sporadic RCCs. The mean age of onset for VHL-related RCCs is 39 years (range, 
 13–70 years), and clear cell RCCs are frequently bilateral.”


    Tumors in von Hippel–Lindau Syndrome: From Head to Toe—Comprehensive State-of-the-Art Review 
Ganeshan D et al.
 RadioGraphics 2018 (in press)
  • “It should be noted that bilateral clear cell RCCs on their own are not diagnostic of VHL, as other hereditary renal tumor syndromes and rarely even sporadic tumors may manifest as bilateral multifocal tumors. However, the presence of bilateral or multifocal clear cell RCCs or tumors in patients younger than 50 years of age is an indication for VHL genetic screening.”


    Tumors in von Hippel–Lindau Syndrome: From Head to Toe—Comprehensive State-of-the-Art Review 
Ganeshan D et al.
 RadioGraphics 2018 (in press)
  • “von Hippel-Lindau disease (VHL) is an autosomal dominant disorder that results from germline mutations in the VHL tumor suppressor gene (chromosome 3p25) and is characterized by benign and malignant tumors in multiple organs.The VHL gene plays a pivotal role in the regulation of the intracellular oxygen-sensing pathway. Inactivation of this gene causes unbridled upregulation of multiple somatic and vascular growth factors, including vascular endothelial growth factor, leading to the development of vascular tumors.Cerebellar and spinal cord hemangioblastomas, retinal angiomas, endolymphatic sac tumors, clear cell RCCs, complex renal cysts, pheochromocytomas, pancreatic cysts and pancreatic neuroendocrine tumors (PNETs), and epididymal cystadenomas are common neoplasms in VHL syndrome . The pancreas (35%–77%), central nervous system (CNS) (44%–72%), and kidneys (25%–60%) are the most commonly involved organs in VHL syndrome.”


    Imaging and Screening of Hereditary Cancer Syndromes 
Venkata S. Katabathina et al.
Radiol Clin N Am 55 (2017) 1293–1309
  • “Tuberous sclerosis complex (TSC) is an autosomal dominant condition caused by inactivating mutations of the TSC1 gene (chromosome 9q34, encodes hamartin) and/or TSC 2 genes (chromosome 16p13, encodes tuberin); tuberin-hamartin complex functions as a tumor suppressor by suppression of the mTOR pathway.CNS lesions in TSC are the primary cause of mortality and morbidity and include cortical and cerebellar tubers, radial migration lines, subependymal nodules, and subependymal giant cell astrocytomas. Gadolinium-enhanced MR imaging of the brain is the imaging modality of choice for diagnosis, screening, and monitoring of intracranial lesions.”


    Imaging and Screening of Hereditary Cancer Syndromes 
Venkata S. Katabathina et al.
Radiol Clin N Am 55 (2017) 1293–1309
  • “Renal lesions are seen in up to 60% of patients with TSC and include angiomyolipomas (AMLs) and renal cysts .Renal AMLs larger than 4 cm or with intralesional aneurysms larger than 5 mm carry increased risk of spontaneous rupture and require prophylactic embolization.Other lesions in TSC include cardiac rhabdomyomas, lung/retroperitoneal lymphangioleiomyomatosis, hepatic AMLs, and sclerotic lesions in the bones.Recent studies suggest that a spectrum of distinctive renal tumors occurs in patients with TSC; tumors occur at a younger age compared with the general population.”


    Imaging and Screening of Hereditary Cancer Syndromes 
Venkata S. Katabathina et al.
Radiol Clin N Am 55 (2017) 1293–1309
  • Renal Cell Carcinoma: Statistics
  • Survival Data 2017
  • Renal Cell Carcinoma: By the Numbers
  • Age Range for Renal Cell Carcinoma
  • Frequency of RCC
  • Renal Cell Carcinoma: Factoids
    • RCC accounts for 85% of renal cancers
    • 210,000 new cases of RCC are diagnosed yearly
    • Clear cell accounts for 70-80% of RCCs, followed by papillary which is 14-17% and chromophobe RCC accounts for 4-8%
    • Clear cell is most likely to metastasize
    • Oncocytomas account gfot up too 4% of lesions
  • AIM: To evaluate the precision of the centrality index (CI) measurement on three-dimensional (3D) volume rendering technique (VRT) images in patients with renal masses, compared to its standard measurement on axial images.

    CONCLUSIONS: The present study showed that VRT and axial images produce almost identical values of CI, with the advantages of greater ease of execution and a time saving of almost 50% for 3D VRT images. In addition, VRT provides an integrated perspective that can better assist surgeons in clinical decision making and in operative planning, suggesting this technique as a possible standard method for CI measurement.
Value of three-dimensional volume rendering images in the assessment of the centrality index for preoperative planning in patients with renal masses.


    Sofia C et al.
Clin Radiol. 2017 Jan;72(1):33-40.

  • CONCLUSIONS: The present study showed that VRT and axial images produce almost identical values of CI, with the advantages of greater ease of execution and a time saving of almost 50% for 3D VRT images. In addition, VRT provides an integrated perspective that can better assist surgeons in clinical decision making and in operative planning, suggesting this technique as a possible standard method for CI measurement.
Value of three-dimensional volume rendering images in the assessment of the centrality index for preoperative planning in patients with renal masses.


    Sofia C et al
Clin Radiol 2017 Jan;72(1):33-40.
  • • Contrast-enhanced multiphasic CT scanning of the abdomen is the diagnostic modality of choice for staging a primary renal tumor. MRI of the abdomen is a suitable substitute when the patient cannot undergo contrast-enhanced CT. If the status of the renal veins and IVC cannot be determined on CT, contrast-enhanced multiphasic 3-D MR venography can be performed.

    • CT of the chest should be used to detect pulmonary metastasis in patients with large or locally advanced tumors. Chest radiography may be sufficient in patients with small primary tumors.

    • In patients with suspicion for metastatic disease based on symptoms, other sites of metastases, or abnormal laboratory findings, brain MRI, and bone scans can be performed.
 

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
  Raghunandan Vikram et al
  J Am Coll Radiol 2016;13:518-525.
  • " Renal involvement in lymphoma commonly occurs in the presence of widespread nodal or extranodal lymphoma and is classified as secondary renal lymphoma (SRL). However, lymphoma may rarely involve the kidneys alone without evidence of disease elsewhere; then, it is termed "primary renal lymphoma".
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • "Renal lymphoma is typically a hypovascular tumor. This feature can help to differentiate it from the more common hypervascular tumors such as RCC, oncocytoma, and angiomyolipoma."
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • "PRLs are often large infiltrative renal tu- mors that extend into the perinephric space and retroperitoneum. However, despite being aggressive tumors, PRLs only rarely involve the inferior vena cava; this characteristic of PRL can help differentiate it from RCC . Careful evaluation to ensure that the epicenter of the tumor is not within the collecting system is helpful in differentiating PRL from urothelial carcinoma."
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • " However, SRL can result in acute renal failure in 6-16% or impaired renal function in nearly one fourth of patients. Morel et al. reported that tumor size larger than 10 cm, involvement of the renal hilum, and diffuse renal infiltration may be associated with a poorer prognosis."
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • "Further, recent studies indicate that in- volvement of the kidneys at the time of initial presentation in diffuse large B-cell lymphoma may be associated with a much higher inci- dence of CNS relapse, which results in poorer prognosis. Hence, it is important to identify renal involvement because patients can then be treated with the addition of rituximab (a monoclonal antibody targeting CD20) to the standard chemotherapy regimen, which may improve both progression-free and over-all survival rates."
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • "Renal lymphomas are associated with var- ious imaging appearances on CT and MRI. The disease may be unilateral or bilateral and may present as focal masses (solitary or multiple) or diffuse infiltrative lesions or may manifest as enlarged kidneys without focal lesions. Unlike RCC, renal lymphoma is typically hypovascular and does not invade the vessels."
    Imaging of Primary and Secondary Renal Lymphoma
     Ganeshan D et al.
    AJR 2013; 201:W712-W719
  • CT of Renal Lymphoma: Patterns
    ● Solitary or multiple
    ● Unilateral or bilateral
    ● May originate from the renal parenchyma or perinephric space
    ● May present as diffuse bilateral nephromegaly without focal lesions
    ● May originate from the renal sinus
  • Renal Lymphoma: Facts
    - Non-Hodgkin Lymphoma usually B-cell Lymphoma
    - Immunocompromised status secondary to organ transplantation and HIV infection may predispose patients to renal lymphoma
    - Usually part of multisystem disease as renal lymphoma primary to the kidneys is rare
  • Secondary Renal Lymphoma: facts
    - Unilateral or bilateral
    - Solitary vs multifocal disease
    - May originate in the parenchyma or the perinephric space
    - Usually hypovascular
    - Renal vein or IVC involvement is rare
  • "Recent studies indicate that in- volvement of the kidneys at the time of initial presentation in diffuse large B-cell lymphoma may be associated with a much higher incidence of CNS relapse, which results in poorer prognosis. Hence, it is important to identify renal involvement because patients can then be treated with the addition of rituximab (a monoclonal antibody targeting CD20) to the standard chemotherapy regimen, which may improve both progression-free and over- all survival rates."

    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan et al.
    AJR 2013; 201:W712–W719
  • "Renal lymphomas are associated with various imaging appearances on CT and MRI. The disease may be unilateral or bilateral and may present as focal masses (solitary or multiple) or diffuse infiltrative lesions or may manifest as enlarged kidneys without focal lesions. Unlike RCC, renal lymphoma is typically hypovascular and does not invade the vessels."

    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan et al.
    AJR 2013; 201:W712–W719
  • "The most common histology of RCC is clear cell adenocarcinoma which accounts for 70% to 80% of cases. Other histologies include papillary (15%), chromophobe (5%), and rare tumors such as renal medullary, Xp11 translocation, and collecting duct carcinomas. Any subtype of RCC can undergo sarcomatoid differentiation, which is associated with early metastases and a poor prognosis."

    Renal cell carcinoma: staging and surveillance
    N. Reed Dunnick
    Abdom Radiol (2016)DOI: 10.1007/s00261-016-0692-0
  • "As many as 5% of patients with RCCs are associated with inherited syndromes. These include hereditary papillary renal cell carcinoma (papillary cancers), hereditary leiomyomatosis renal cell carcinoma (papillary cancers), von-Hippel Lindau Disease (clear cell cancers), tuberous sclerosis complex (clear cell cancers), and Birt–Hogg– Dube Syndrome (chromophobe renal cancers). Al- though not a hereditary cancer, renal medullary carcinomas develop in patients with sickle cell trait."

    Renal cell carcinoma: staging and surveillance
    N. Reed Dunnick
    Abdom Radiol (2016)DOI: 10.1007/s00261-016-0692-0
  • "Lymph node involvement is determined by size criteria. Renal hilar, paraaortic, and paracaval (regional) lymph nodes with a short-axis diameter greater than 1 cm are considered to be involved. Although sensitivities for detecting involvement are high, false positives are common and are usually due to benign reactive changes. Regional lymph node involvement is most common when the primary tumor is large, stage 2."

    Renal cell carcinoma: staging and surveillance
    N. Reed Dunnick
    Abdom Radiol (2016)DOI: 10.1007/s00261-016-0692-0
  • " Renal cell carcinoma (RCC) accounts for 2%-3% of all visceral malignancies. An estimated 61,560 new cases of RCC are diagnosed per year in the United States, resulting in approximately 14,080 deaths  from cancers of the kidney and renal pelvis. The incidence of RCC seems to be increasing in the United States compared with the past decade. The incidence in men is 1.6 times greater than that in women. Metastatic disease at presentation varies with the patient series, but it typically occurs in approximately 1 in 10 patients. The most common sites of distant metastases, in descending order, are the lungs, bone, retroperitoneal and mediastinal nodes, liver, brain, and multiple sites."

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
    Raghunandan Vikram et al.
    JACR (in press)
    DOI: http://dx.doi.org/10.1016/j.jacr.2016.01.021
  • " Renal cell carcinoma accounts for 2%-3% of all visceral malignancies. Preoperative imaging can provide important staging and anatomic information to guide treatment decisions. Size of the primary tumor and degree of local invasion, such as involvement of perinephric fat or renal sinus fat, and tumor thrombus in renal veins and inferior vena cava are important detriments to local staging of primary tumor. Both kidneys are assessed for presence of other synchronous lesions."

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
    Raghunandan Vikram et al.
    JACR (in press)
    DOI: http://dx.doi.org/10.1016/j.jacr.2016.01.021
  • Renal cell carcinoma (RCC) accounts for 2%-3% of all visceral malignancies. An estimated 61,560 new cases of RCC are diagnosed per year in the United States, resulting in approximately 14,080 deaths  from cancers of the kidney and renal pelvis. The incidence of RCC seems to be increasing in the United States compared with the past decade. The incidence in men is 1.6 times greater than that in women.

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
    Raghunandan Vikram et al.
    JACR (in press)
    DOI: http://dx.doi.org/10.1016/j.jacr.2016.01.021
  • "The incidence in men is 1.6 times greater than that in women. Metastatic disease at presentation varies with the patient series, but it typically occurs in approximately 1 in 10 patients. The most common sites of distant metastases, in descending order, are the lungs, bone, retroperitoneal and mediastinal nodes, liver, brain, and multiple sites."

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
    Raghunandan Vikram et al.
    JACR (in press)
    DOI: http://dx.doi.org/10.1016/j.jacr.2016.01.021
  • ■ Contrast-enhanced multiphasic CT scanning of the abdomen is the diagnostic modality of choice for staging a primary renal tumor. MRI of the abdomen is a suitable substitute when the patient cannot undergo contrast-enhanced CT. If the status of the renal veins and IVC cannot be determined on CT, contrast-enhanced multiphasic 3-D MR venography can be performed.
    ■ CT of the chest should be used to detect pulmonary metastasis in patients with large or locally advanced tumors. Chest radiography may be sufficient in patients with small primary tumors.
    ■ In patients with suspicion for metastatic disease based on symptoms, other sites of metastases, or abnormal laboratory findings, brain MRI, and bone scans can be performed."

    ACR Appropriateness Criteria Renal Cell Carcinoma Staging
    Raghunandan Vikram et al.
    JACR (in press)
    DOI: http://dx.doi.org/10.1016/j.jacr.2016.01.021
  • “ Adequate preoperative radiologic assessment provides the treating physician with information critical in determining the sequence of treatments, role of nephron sparing surgery, surgical approach, and timing of systemic therapy for metastatic disease.”
    Renal Cell Carcinoma: What the Surgeon and Treating Physician Need to Know
    Chapin BF et al.
    AJR 2011; 196:1255-1282
  • Multifocal Renal Cell Carcinoma: Etiology
    - Sporadic
    - Von Hippel-Lindau disease
    - Birt-Hogg-Dube syndrome
    - Hereditary papillary renal cell carcinoma
  • “ CT texture analysis reflecting tumor heterogeneity is an independent factor associated with time to progression and has potential as a predictive imaging biomarker of response of metastatic renal cancer to targeted therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ Changes in tumor heterogeneity after two cycles of TKI therapy for metastatic renal cancer correlates with measured time to progression; by using a threshold change of -2% or less for uniformity at a coarse scale value of 2.5; Kaplan-Meier curves of the proportion of patients without disease progression were significantly different and better than those for standard response assessment after two cycles of TKI therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The addition of texture analysis to standard response assessment may improve the prediction of response to TKIs in patient with metastatic renal cell carcinoma.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The genetic makeup of clear cell RCCs (ccRCCs) affects their imaging features at multidetector CT examinations. Multidetector CT imaging characteristics may help suggest differences at the cytogenetic level among ccRCCs.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ Imaging features at multiphasic multidetector CT correlate with cytogenetic characteristics of ccRCCs, which may affect patient prognosis and possibly help predict response to molecular targeted therapies.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with the loss of the Y chromosome enhanced more than those without the anomaly in male patients during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 5 enhanced more than those with disomy 5  during the excretory phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 7 enhanced less than those with disomy 7  during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery. However clinical understaging in 15% of cT1b tumors should be considered in treatment  decision making. Clinical tumor size had an independent impact on cancer specific survival and revealed a higher prognostic value compared with pathologic tumor size.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ The mean clinical and pathologic tumor size was 5.93 and 5.53 cm respectively. Integration of pathologic tumor size instead of clinical tumor size into multivariable analysis resulted in a reduction of predictive accuracy of 2.3%”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • What is a small renal mass?
    - “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    - Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    - Stakhovsky O et al.
    - AJR 2011; 196:1267-1273
  • “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • “ Many small renal masses are not RCCs but benign lesions (30% of tumors <2cm in diameter and 20% of those greater than 4 cm in diameter).”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Oncocytoma
    - Angiomyolipoma (AML)
    - Complex renal cysts
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Clear cell RCC
    - Papillary RCC
    - Chromophobe RCC
  • Treatment of a Renal Mass
    - Radical nephrectomy
    - Partial nephrectomy
    - Laparoscopic procedures ( including robotic nephrectomy and partial nephrectomy)
    - Thermal ablation therapy (radiofrequency ablation, cryoablation)
  • Treatment of a Small Renal Mass: Options
    Biopsy of the mass
    Active surveillance and monitoring with CT at;
    - 3, 6 and 12 months
    - Every 6 months till 2 years
    - Yearly thereafter
  • “ The incidental finding of a renal mass is relatively common at unenhanced CT, but imaging criteria can be used for reliable identification of most of these lesions as benign without further workup. Mean attenuation alone appears reliable for determining which renal mass need further evaluation.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ Masses (1cm or larger) containing fat or with attenuation less than 20 HU or greater than 70 HU were considered benign if they did not contain thickened walls or septations, three of more septations, mural nodules, or thick calcifications. Masses with attenuation between 20 and 70 HU or any of these features were considered indeterminate.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ When urinary tract calculi are identified at MDCTU, the rate of detection of other potential causes of hematuria is not different from that in MDCTU examinations without calculi. The contrast enhanced portion of the MDCTU examination is needed even if calculi are seen because important pathologic changes are diagnosed only after the contrast enhanced phase.”
    Hematuria Evaluation with MDCT Urography: Is A Contrast Enhanced Phase Needed When Calculi Are Detected in the Unenhanced Phase
    Song JH et al.
    DOI:10.2214/AJR.10.5968
  • What follow-up is recommended for small solid renal masses?

    "Computed tomography or MRI at 3 to 6 months, 12 months, and then yearly; the interval of observation may be varied (eg, shorter intervals if the mass is enlarging); the duration of observation may be individualized. Observation may be considered for a solid renal mass of any size in a patient with a limited life expectancy or comorbidities that increase the risk of treatment, particularly when the mass is small."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "In general, large (>3cm) solid renal masses are likely malignant; similarly, the smaller a solid mass, the more likely it is benign. In addition, a small renal cell carcinoma is more likely to be low grade and indolent behaving than a larger one.Therefore we have suggested that solid masses <1cm be observed."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "This white paper which represents the collective experience of the Incidental Findings Committee, using a less formal process of repeated reviews and revisions of the draft document, does not represent official ACR policy. For these reasons, this white paper should not be used to establish the legal standard of care in any particular situation."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "The committee has used a consensus method based on repeated reviews and revisions of this document and a collective review and interpretation of relevant literature. This white paper provides guidance developed by this committee for addressing incidental findings in the kidneys, liver , adrenal gland and pancreas"

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • Mesenchymal Renal Neoplasms: Malignant
    - Leiomyosarcoma
    - Rhabdomyosarcome
    - Angiosarcoma
    - Osteosarcoma
    - Synovial sarcoma
    - Fibrosarcoma
    - Malignant fibrous histiocytoma
    - Solitary fibrous tumor
  • Kidney: Transitional Cell Carcinoma of the Kidney: Facts
    - Multiplicity common

    - Distal ureter most common site in the ureter (73%)

    - metastases common to renal vein, IVC and local nodes

    - Tumors may occasionally have fine stippled calcifications

  • Kidney: Transitional Cell Carcinoma of the Kidney: Facts
    - 15% of malignant renal tumors

    - More common in men (2-1)

    - Incidences peaks in 7th decade

    - Upper tract TCC occurs in 2% of patient with lower tract disease, but 40% of patients with upper tract disease develop lower tract disease

     

  • "The hallmark of TCC is multiplicity and recurrence. Nearly 2-4% of patients with bladder cancer develop upper tract TCC, but 40% of patients with upper tract TCC develop bladder cancer."

    Imaging and Staging of Transitional Cell Carcinoma: Part 2, Upper Urinary Tract
    Vikram R et al
    AJR 2009;192:1488-1493

  • Renal Mass in 17 yr old African American female

    - Renal medullary carcinoma (if patient has sickle trait)
    - Rhabdoid tumor
    - Mesoblastic nephroma
    - Wilms’ tumor
    - Renal cell carcinoma, sarcomatoid variant
  • Solitary Renal Mass in a Older Child

    - Wilms’ tumor
    - Clear cell sarcoma of the kidney
    - Mesoblastic nephroma
    - Rhabdoid tumor
    - Renal cell carcinoma
    - Teratoma
    - Renal medullary carcinoma
  • Fibrous Tumor of the Kidney

    - Rare tumor (less tha 30 reported cases)
    - Immunohistochemically tumor cells are positive for CD34, CD99 and bcl-2.
    - Spindle cell neoplasm with hypervascular pattern like hemangiopericytoma like growth pattern
    - Prognosis usually favorable
  • Fibrous Tumor of the Kidney

    - Pre-op diagnosis usually renal cell carcinoma
    - Tumors usually in 8-12 cm range
    - Although these tumors are usually benign reports of malignant transformation have occurred
    - Looks similar to solitary fibrous tumor of the pleura (most common site for SFT)
  • WHO Histological Classification of Benign Renal Neoplasms

    - Renal cell tumors
    - Metanephric tumors
    - Mesenchymal tumors
    - Mixed epithelial and mesenchymal tumors
  • Renal Cell Tumors

    - Oncocytoma
    - Papillary adenoma
  • Metanephric Tumors

    - Metanephric adenoma
    - Metanephric adenofibroma
    - Metanephric stromal tumor
  • "High resolution images obtained with thin section MDCT can play an increasing role in the accurate detection and assessment of the upper urinary tract TCC."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • "High resolution images obtained with thin section MDCT can play an increasing role in the accurate detection and assessment of the upper urinary tract TCC.Local extension of tumors and location of the tumor relative to the kidney and adjacent organs are well shown on MPR and 3D images."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • "Local extension of tumors and location of the tumor relative to the kidney and adjacent organs are well shown on MPR and 3D images."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • Proportion of Solid Renal Masses That are Benign:

    Size (cm)Proportion
    All sizes12.8%
    0 to < 146.3%
    1 to < 222.4%
    2 to < 322.0%
    3 to < 419.9%
    4 to < 59.9%
    5 to < 613.0%
    6 to < 74.5%
    > 76.3%
  • Fact: small renal masses removed at surgery are often benign
    Solid Renal Tumors: An Analysis of Pathological Features Related to Tumor Size
    Frank I et al.
    J Urol 2003; 170:2217-2220
  • Genitourinary Lymphoma: CT Patterns of Involvement

    - 3-8% incidence of involvement
    - Kidney is the most common site of involvement
    - Renal metastases can mimic lymphoma
    - Bladder involvement can occur in up to 8% of patients
  • Renal Lymphoma: CT Patterns of Involvement

    - Multiple circumscribed masses
    - Direct infiltration from adjacent nodes
    - Solitary mass
    - Isolated perinephric mass
  • Renal Cell Carcinoma: Sites of Metastases

    - 25-30% have metastases at time of presentation
    - 20% have locally advanced disease at presentation
    - 50% of patients develop metastases even with nephrectomy for early stage disease
  • Perinephric Masses on CT: Differential Diagnosis

    - Lymphoma
    - Metastases (especially melanoma)
    - Myeloma
    - Urinomas
    - Hemmorrhage
    - Infection
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Erdheim Chester disease
  • "In the corticomedullary phase, attenuation values of renal clear cell carcinoma were significantly higher than those of renal papillary carcinoma. In renal clear cell carcinoma the mean attenuation value was 152.6 HU (range 90-256 HU); in renal papillary carcinoma, the value was 61.8 HU (range 38-123 HU)."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • "In the corticomedullary phase, attenuation values of renal clear cell carcinoma were significantly higher than those of renal papillary carcinoma. The accuracy was 95.7%; the sensitivity 98.3% and the specificity, 92% when using 100HU as the cutoff value."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • "In renal clear cell carcinoma, the mean nephrographic attenuation value was 105 HU (range 88-120HU); in renal papillary carcinoma it was 67.3 HU (range 38-88HU).The accuracy was 94.8%; the sensitivity 95.2%, qnd the specificity 92.3% when using 85 HU as the cutoff value."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • What is the importance of predicting papillary vs clear cell renal cell carcinoma?

    - Management decisions including partial vs classic nephrectomy
    - Open vs laprascopic procedure
    - Follow up if conservative management is chosen
  • "Certain imaging features and the degree of enhancement may be helpful in differentiating subtypes of renal cortical tumors."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Ninety percent of clear cell renal cell carcinomas (RCCs) are hypervascular and demonstrate a heterogeneous enhancing pattern of mixed enhancing solid soft tissue components and low attenuation necrotic or cystic areas."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Seventy-five percent of papillary renal cell carcinomas (RCCs) are hypovascular, and 90% of all papillary tumors demonstrate a homogeneous or peripheral enhancement pattern."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Caoili and associates reviewed the CT urographic appearance of pathologically proved transitional cell carcinoma of the renal collecting systems and ureters and correlated the findings from CT urography with those from pathologic examination. Twenty four (89%) of the 27 neoplasms could be identified at CT Urography."

    CT Urography: Technique and Applications
    Caoili EM, Cohan RH
    Categorical Course RSNA 2006; 11-22
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan seperated by 50 seconds. The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely."

    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan separated by 50 seconds."

    Differentiation of Renal Neoplasms From High Density Cysts: Use of Attenuation Changes Between the Corticomedullary and Nephrographic Phases of Computed Tomography
    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely." Differentiation of Renal Neoplasms From High Density Cysts: Use of Attenuation Changes Between the Corticomedullary and Nephrographic Phases of Computed Tomography
    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan separated by 50 seconds. The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely."
  • Perinephric Mass: Differential Dx

    - Proliferative diseases
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Rosai-Dorfman disease
    - Erdheim-Chester disease
  • Perinephric Mass: Differential Dx

    - Tumors
    - Renal cell carcinoma
    - Lymphoma
    - Metastases (melanoma)
    - Retroperitoneal tumors by direct extension
  • Perinephric Mass: Differential Dx

    - Fluid
    - Hematoma
    - Urinoma
    - Abscess
    - Pancreatic pseudocyst
  • Perinephric Mass: Differential Dx

    - Tumors
    - Fluid
    - Inflammation
    - Proliferative diseases
  • Transitional Cell Carcinoma: Facts

    - Clinical presentation usually hematuria
    - Account for up to 10% or neoplasms of the kidney
    - Often multifocal
    - Age range is 60-70’s
  • Renal Cell Carcinoma: Facts

    - 85% of all renal cancers in adults
    - 30,000 new cases diagnosed in the US each year
    - M>F by 2-1
    - Peak incidence is age 50-70
    - Tumors are adenocarcinomas
  • Renal Cell Carcinoma: Risk Factors

    - Acquired cystic renal disease
    - Chronic renal failure
    - Von Hippel Lindau disease
    - Smoking
    - Hereditary renal cell carcinoma
  • von Hippel-Lindau Disease: Facts

    - Autosomal dominant familial tumor syndrome
    - High penetrance with variable expression
    - Prevalence of one in 50,000
    - Defect in short arm of chromosome 3
  • von Hippel-Lindau Disease: organ involvement

    - Kidney
    - Adrenal
    - Pancreas
    - Brain
    - Spinal cord
    - Retina
  • von Hippel-Lindau Disease: Renal Pathology

    - Renal cysts- occur in 50-75% of patients and are usually multiple and bilateral
    - Renal cell carcinoma-occur in 28-45% of patients and occur at a younger age (30-36 yrs). The lesions are often multiple and bilateral and may be hypovascular or cystic lesions with mural nodules
  • von Hippel-Lindau Disease: Adrenal Pathology

    - Pheochromocytoma
    - Occur in up to 30% of families with VHL
    - They are bilateral in up to 50% of patients with a malignancy rate of around 10%
    - Up to 18% are extraadrenal in location
  • von Hippel-Lindau Disease: Pancreatic Pathology

    - Occur in up to 77% of patients
    - Lesions include
    - Simple pancreatic cysts
    - Serous cystadenomas
    - Neuroendocrine tumors
    - Pancreatic carcinoma
  • von Hippel-Lindau Disease: Uncommon Pathology

    - Liver cysts
    - Cystadenomas of the epididymis and broad ligament
  • "In evaluating Robson stage I of renal cell carcinoma, we were able to diagnose fat infiltration on 1-mm scans with 96% sensitivity, 93% specificity, and 95% accuracy; the positive and negative predictive values were, respectively, 100% and 93%."

    High-Resolution Multidetector CT in the Preoperative Evaluation of Patients with Renal Cell Carcinoma
    Catalano C et al.
    AJR 2003; 180:1271-1277
  • “A minority of small RCCs do not reach either a 15- or 20-HU enhancement threshold and might be misinterpreted as a hyperattenuating cyst. Most RCCs below these enhancement thresholds are papillary RCC.”

    Enhancement Threshold of Small (< 4 cm) Solid Renal Masses on CT 
 Al Harbi F et al.
AJR 2016; 206:554–558
  • “High-attenuation renal cysts containing blood or proteinaceous material can be mistaken for a small renal mass because of pseudoenhancement and therefore can lead to an unnecessary biopsy. Conversely, if there are renal cell cancers with nonsignificant enhancement, they may be misinterpreted as hyperattenuating cysts. An enhancement threshold of 15–20 HU is considered indeterminate, whereas enhancement of greater than 20 HU is considered sufficient to confirm the solid nature of a renal mass.”

    Enhancement Threshold of Small (< 4 cm) Solid Renal Masses on CT 
 Al Harbi F et al.
AJR 2016; 206:554–558
  • “The mean attenuation of clear cell RCC was significantly greater than that of papillary RCC and chromophobe RCC in the corticomedullary phase (clear cell, 139.7 HU; papillary, 56.8 HU [p = 0.003]; chromophobe, 85.4 HU [p = 0.005]) and early excretory phase (clear cell, 86.9 HU; papillary, 73.4 HU [p = 0.03]; chromophobe, 68.2 HU [p = 0.02]). It was also significantly greater than that of fat-poor angiomyolipoma in the corticomedullary phase (139.7 vs 99.6 HU, p = 0.02).“


    Differentiation of Clear Cell Renal Cell Carcinoma From Other Subtypes and Fat-Poor Angiomyolipoma by Use of Quantitative Enhancement Measurement During Three-Phase MDCT 
Kim SH et al
AJR 2016; 206:W21–W28 
  • “ Despite extensive study of morphologic and quantitative criteria at conventional imaging, no CT or MRI techniques can reliably distinguish solid benign tumors, such as oncocytoma and lipid poor angiomyolipoma, from malignant renal tumors.”
    Solid Renal Masses: What the Numbers Tell Us
    Kang SK et al.
    AJR 2014; 202:1196-1206
  • “ MRI can also potentially provide incremental value after CT findings when a benign mass or pseudolesion is questioned.”
    Solid Renal Masses: What the Numbers Tell Us
    Kang SK et al.
    AJR 2014; 202:1196-1206
  • Renal Lymphoma
    - Although up to 50 % of patients with lymphoma have renal involvement at autopsy, renal lymphoma is usually asymptomatic and detected incidentally at staging or follow up CT.
    - Lymphoma can involve the kidneys by hematogenous spread, lymphatic dissemination or direct extension from retroperitoneal lymphadenopathy
  • Lymphoma can involve the kidneys by hematogenous spread, lymphatic dissemination or direct extension from retroperitoneal lymphadenopathy. The various CT appearances of renal lymphoma reflect these patterns of involvements:
    - Diffusely enlarged kidneys with heterogeneous enhancement.
    - Intra renal extension of a retroperitoneal mass.
    - Multiple hypoattenuating masses
    - Solitary mass, which may be difficult to differentiate from a renal cell carcinoma
    - Perinephric soft tissue mass that may mimic a hematoma.
  • Bilateral Renal Masses:Differential Dx
    - Renal cysts
    - Renal lymphoma
    - Renal carcinoma
    - Angiomyolipomas
    - Renal abscesses
    - Metastases to the kidney
  • “ Renal lymphoma has a variable imaging spectrum and may mimic renal cell carcinoma. An awareness of the typical and atypical imaging features of both primary and secondary renal lymphomas can help the radiologist to suggest these diagnoses and recommend biopsy when appropriate.”
    Imaging of primary and secondary renal lymphoma
    Ganeshan D et al.
    AJR Am J Roentgenol. 2013 Nov;201(5):W712-9
  • MASS Criteria for Renal Cell Carcinoma (Clear Cell)
    - MASS- morphology, attenuation, size and structure
    - Goal is to use more factors than simply size which may not be valuable in these patients
    - “marked central necrosis” becomes important
  • MASS Criteria for Renal Cell Carcinoma (Clear Cell)
    - Favorable response
    - Decrease in tumor size of 20% or more
    - Solid enhancing lesion shows central necrosis or marked decreased attenuation (- 40HU) without new lesions
    - Other responses are indeterminate response and unfavorable response (tumor size increases 20% or absence of central necrosis or new lesions)
  • “On CT, many papillary RCCs do not enhance, indicating that assessment of enhancement alone is insufficient for differentiating papillary RCCs from hyperdense cysts.”
    Differentiation of Papillary Renal Cell Carcinoma Subtypes on CT and MRI
    Egbert ND et al.
    AJR 2013; 201:347-355
  • “Reliance on the presence or absence of enhancement on CT to determine whether a mass is solid or cystic is inadequate. In such cases, the presence of tumor heterogeneity is a more reliable clue that the mass is solid.”
    Differentiation of Papillary Renal Cell Carcinoma Subtypes on CT and MRI
    Egbert ND et al.
    AJR 2013; 201:347-355
  • “ Nearly one third of papillary RCCs in our patient population had atypical features on histology. On CT and MRI, there are some significant differences in imaging features between type 1 and type 2 tumors; however substantial overlap precludes categorization on a per patient basis. On CT, many papillary RCCs do not enhance, indicating that assessment of enhancement alone is insufficient for differentiating papillary RCCs from hyperdense cysts.”
    Differentiation of Papillary Renal Cell Carcinoma Subtypes on CT and MRI
    Egbert ND et al.
    AJR 2013; 201:347-355
  • Perirenal Space Pathology
    - Solitary soft tissue masses (RCC, lymphangioma,hemangioma)
    - Rindlike soft tissue lesions (lymphoma, retroperitoneal fibrosis, Erdheim Chester disease)
    - Multifocal soft tissue masses (metastases)
    - Masses containing macroscopic fat (AML, extramedullary hematopoiesis)
    - Neoplastic and Nonneoplastic Proliferative Disorders of the Perirenal Space: Cross-sectional Imaging Findings
    - Surabhi VR et al
    - RadioGraphics 2008; 28:1005-1017
  • Infiltration of the Perirenal Space: Differential Dx
    - Lymphoma
    - Retroperitoneal fibrosis
    - Erdheim-Chester Disease
    - Metastatic disease
    - Extramedullary hematopoiesis
  • Hereditary Renal Tumor Syndromes
    - Von Hippel-Lindau syndrome
    - Tuberous Sclerosis
    - Birt-Hogg-Dube syndrome
    - Hereditary Papillary RCC
    - Hereditary Leiomyomatosis and renal cell carcinoma
    - Bilateral Wilms tumor
    - Renal medullary carcinoma
    Hereditary Renal Tumor Syndromes; Imaging Findings and Management Strategies
    Northrup BE et al.
    AJR 2012;99:1294-1304
  • von Hippel-Lindau syndrome: Facts
    - Autosomal dominant with variable expressivity
    - Mutation in the VHL tumor suppressor gene on chromosome 3
    - First detected at average of of 30.5
    - Renal cell carcinoma accounts for half the deaths in VHL patients
  • von Hippel-Lindau syndrome: CT Findings
    - Multiple renal cysts (59-63% of patients)
    - Clear cell RCC develop in 24-45% of patients with VHL
    - RCCs are often bilateral (75%) and multiple
    - CT appearance is either a vascular mass or or an enhancing mural nodule
  • von Hippel-Lindau syndrome: Extrarenal Findings
    - Pancreatic cysts (50-91%) and neuroendocrine tumors (5-17%)
    - Pheochromocytomas (50% bilateral and 15-18% are extra-adrenal
    - Paragangliomas
    - Cystsadenoma of the epididymis or broad ligament
    - Retinal angiomas
    - Hemangioblastomas of the cerebellum, brain stem and spinal cord
  • Tuberous Sclerosis: facts
    - AKA Bourneville-Pringle disease
    - Autosomal dominant neurocutaneous syndrome
    - Caused by mutations of the TSC1 or TSC2 gene
    - Primary renal findings are angiomyolipomas and cysts.
    - AMLs occur in up to 80% of patients
  • Tuberous Sclerosis: CT Findings in the Kidney
    - Renal angiomyolipomas (80%) and cysts (47%) are most common renal findings
    - Up to 95% of renal angiomyolipomas in TS patients will contain fat
    - Clear cell RCC occurs in up to 4% of the patients with TS
  • Tuberous Sclerosis: CT Findings Beyond the Kidney
    - Neurological findings like cortical tubers, subependymal nodules, giant cell astrocytoma
    - Dermatologic findings include facial angiofibromas, maculles and shagreen patches
    - Hepatic AMLs are seen in 13% of cases
    - Lymphangioleiomyomatosis with pulmonary cysts is common (34% of woman, <1% of men)
  • Birt-Hogg-Dube Syndrome: facts
    - Autosomal dominant  disorder caused by mutation in the folliculin (FLCN)gene
    - 15-30% develop renal tumors with average age of diagnosis of 50.7 years
    - Renal tumors are either hybrid tumors or chromophobe RCCs.
    - 80% of patient have pulmonary cysts in the lower lung fields
  • Hereditary Papillary RCC: Facts
    - Autosomal dominant gene with mutation of the c-MET gene on chromosome 7
    - Patients develop multiple bilateral papillary RCCS
    - The RCCs are less aggressive than other RCCs
  • Hereditary Leiomyomatosis and Renal Cell Carcinoma: Facts
    - Autosomal dominant disorder
    - Syndrome with cutaneous leiomyomata, uterine leiomyomatosis and type 2 papillary RCCs
    - Usually solitary mass but aggressive
  • “ Adequate preoperative radiologic assessment provides the treating physician with information critical in determining the sequence of treatments, role of nephron sparing surgery, surgical approach, and timing of systemic therapy for metastatic disease.”
    Renal Cell Carcinoma: What the Surgeon and Treating Physician Need to Know
    Chapin BF et al.
    AJR 2011; 196:1255-1282
  • Multifocal Renal Cell Carcinoma: Etiology
    - Sporadic
    - Von Hippel-Lindau disease
    - Birt-Hogg-Dube syndrome
    - Hereditary papillary renal cell carcinoma
  • “ CT texture analysis reflecting tumor heterogeneity is an independent factor associated with time to progression and has potential as a predictive imaging biomarker of response of metastatic renal cancer to targeted therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ Changes in tumor heterogeneity after two cycles of TKI therapy for metastatic renal cancer correlates with measured time to progression; by using a threshold change of -2% or less for uniformity at a coarse scale value of 2.5; Kaplan-Meier curves of the proportion of patients without disease progression were significantly different and better than those for standard response assessment after two cycles of TKI therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The addition of texture analysis to standard response assessment may improve the prediction of response to TKIs in patient with metastatic renal cell carcinoma.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The genetic makeup of clear cell RCCs (ccRCCs) affects their imaging features at multidetector CT examinations. Multidetector CT imaging characteristics may help suggest differences at the cytogenetic level among ccRCCs.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ Imaging features at multiphasic multidetector CT correlate with cytogenetic characteristics of ccRCCs, which may affect patient prognosis and possibly help predict response to molecular targeted therapies.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with the loss of the Y chromosome enhanced more than those without the anomaly in male patients during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 5 enhanced more than those with disomy 5  during the excretory phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 7 enhanced less than those with disomy 7  during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery. However clinical understaging in 15% of cT1b tumors should be considered in treatment  decision making. Clinical tumor size had an independent impact on cancer specific survival and revealed a higher prognostic value compared with pathologic tumor size.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ The mean clinical and pathologic tumor size was 5.93 and 5.53 cm respectively. Integration of pathologic tumor size instead of clinical tumor size into multivariable analysis resulted in a reduction of predictive accuracy of 2.3%”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • What is a small renal mass?
    - “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    - Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    - Stakhovsky O et al.
    - AJR 2011; 196:1267-1273
  • “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • “ Many small renal masses are not RCCs but benign lesions (30% of tumors <2cm in diameter and 20% of those greater than 4 cm in diameter).”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Oncocytoma
    - Angiomyolipoma (AML)
    - Complex renal cysts
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Clear cell RCC
    - Papillary RCC
    - Chromophobe RCC
  • Treatment of a Renal Mass
    - Radical nephrectomy
    - Partial nephrectomy
    - Laparoscopic procedures ( including robotic nephrectomy and partial nephrectomy)
    - Thermal ablation therapy (radiofrequency ablation, cryoablation)
  • Treatment of a Small Renal Mass: Options
    Biopsy of the mass
    Active surveillance and monitoring with CT at;
    - 3, 6 and 12 months
    - Every 6 months till 2 years
    - Yearly thereafter
  • “ The incidental finding of a renal mass is relatively common at unenhanced CT, but imaging criteria can be used for reliable identification of most of these lesions as benign without further workup. Mean attenuation alone appears reliable for determining which renal mass need further evaluation.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ Masses (1cm or larger) containing fat or with attenuation less than 20 HU or greater than 70 HU were considered benign if they did not contain thickened walls or septations, three of more septations, mural nodules, or thick calcifications. Masses with attenuation between 20 and 70 HU or any of these features were considered indeterminate.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ When urinary tract calculi are identified at MDCTU, the rate of detection of other potential causes of hematuria is not different from that in MDCTU examinations without calculi. The contrast enhanced portion of the MDCTU examination is needed even if calculi are seen because important pathologic changes are diagnosed only after the contrast enhanced phase.”
    Hematuria Evaluation with MDCT Urography: Is A Contrast Enhanced Phase Needed When Calculi Are Detected in the Unenhanced Phase
    Song JH et al.
    DOI:10.2214/AJR.10.5968
  • “ Adequate preoperative radiologic assessment provides the treating physician with information critical in determining the sequence of treatments, role of nephron sparing surgery, surgical approach, and timing of systemic therapy for metastatic disease.”
    Renal Cell Carcinoma: What the Surgeon and Treating Physician Need to Know
    Chapin BF et al.
    AJR 2011; 196:1255-1282
  • Multifocal Renal Cell Carcinoma: Etiology
    - Sporadic
    - Von Hippel-Lindau disease
    - Birt-Hogg-Dube syndrome
    - Hereditary papillary renal cell carcinoma
  • “ CT texture analysis reflecting tumor heterogeneity is an independent factor associated with time to progression and has potential as a predictive imaging biomarker of response of metastatic renal cancer to targeted therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ Changes in tumor heterogeneity after two cycles of TKI therapy for metastatic renal cancer correlates with measured time to progression; by using a threshold change of -2% or less for uniformity at a coarse scale value of 2.5; Kaplan-Meier curves of the proportion of patients without disease progression were significantly different and better than those for standard response assessment after two cycles of TKI therapy.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The addition of texture analysis to standard response assessment may improve the prediction of response to TKIs in patient with metastatic renal cell carcinoma.”
    Assessment of Response to Tyrosine Kinase Inhibitors in Metastatic Renal Cell Cancer: CT Texture as a Predictive Biomarker
    Goh V et al.
    Radiology 2011; 261:15-171
  • “ The genetic makeup of clear cell RCCs (ccRCCs) affects their imaging features at multidetector CT examinations. Multidetector CT imaging characteristics may help suggest differences at the cytogenetic level among ccRCCs.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ Imaging features at multiphasic multidetector CT correlate with cytogenetic characteristics of ccRCCs, which may affect patient prognosis and possibly help predict response to molecular targeted therapies.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with the loss of the Y chromosome enhanced more than those without the anomaly in male patients during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 5 enhanced more than those with disomy 5  during the excretory phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ ccRCCs with trisomy 7 enhanced less than those with disomy 7  during the corticomedullary phase at multiphasic multidetector CT examinations.”
    Clear Cell Renal Cell Carcinoma: Multiphasic Multidetector CT Imaging Features Help Predict Genetic Karyotypes
    Sauk SC et al.
    Radiology 2011; 261:854-862
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery. However clinical understaging in 15% of cT1b tumors should be considered in treatment  decision making. Clinical tumor size had an independent impact on cancer specific survival and revealed a higher prognostic value compared with pathologic tumor size.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ CT significantly overestimated tumor size in the overall study group, but this overestimation is unlikely to be of clinical importance regarding the decision about radical versus nephron sparing surgery.”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • “ The mean clinical and pathologic tumor size was 5.93 and 5.53 cm respectively. Integration of pathologic tumor size instead of clinical tumor size into multivariable analysis resulted in a reduction of predictive accuracy of 2.3%”
    Difference Between Clinical and Pathologic Renal Tumor Size, Correlation with Survival, and Implications for Patient Counseling Regarding Nephron-Sparing Surgery
    Brookman-May, S et al.
    AJR 2011; 197:1137-1145
  • What is a small renal mass?
    - “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    - Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    - Stakhovsky O et al.
    - AJR 2011; 196:1267-1273
  • “ Small renal masses have been defined as enhancing tumors less than 4 cm in diameter.”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • “ Many small renal masses are not RCCs but benign lesions (30% of tumors <2cm in diameter and 20% of those greater than 4 cm in diameter).”
    Small Renal Mass: What the Urologist Needs to Know for Treatment Planning and Assessment of Treatment Results
    Stakhovsky O et al.
    AJR 2011; 196:1267-1273
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Oncocytoma
    - Angiomyolipoma (AML)
    - Complex renal cysts
  • Small Renal Tumors: Differential Dx
    - Renal cell carcinoma
    - Clear cell RCC
    - Papillary RCC
    - Chromophobe RCC
  • Treatment of a Renal Mass
    - Radical nephrectomy
    - Partial nephrectomy
    - Laparoscopic procedures ( including robotic nephrectomy and partial nephrectomy)
    - Thermal ablation therapy (radiofrequency ablation, cryoablation)
  • Treatment of a Small Renal Mass: Options
    Biopsy of the mass
    Active surveillance and monitoring with CT at;
    - 3, 6 and 12 months
    - Every 6 months till 2 years
    - Yearly thereafter
  • “ The incidental finding of a renal mass is relatively common at unenhanced CT, but imaging criteria can be used for reliable identification of most of these lesions as benign without further workup. Mean attenuation alone appears reliable for determining which renal mass need further evaluation.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ Masses (1cm or larger) containing fat or with attenuation less than 20 HU or greater than 70 HU were considered benign if they did not contain thickened walls or septations, three of more septations, mural nodules, or thick calcifications. Masses with attenuation between 20 and 70 HU or any of these features were considered indeterminate.”
    Incidental Findings of Renal Masses at Unenhanced CT: Prevalence and Analysis of Features for Guiding Management
    O’connor SD et al.
    AJR 2011; 197:139-145
  • “ When urinary tract calculi are identified at MDCTU, the rate of detection of other potential causes of hematuria is not different from that in MDCTU examinations without calculi. The contrast enhanced portion of the MDCTU examination is needed even if calculi are seen because important pathologic changes are diagnosed only after the contrast enhanced phase.”
    Hematuria Evaluation with MDCT Urography: Is A Contrast Enhanced Phase Needed When Calculi Are Detected in the Unenhanced Phase
    Song JH et al.
    DOI:10.2214/AJR.10.5968
  • What follow-up is recommended for small solid renal masses?

    "Computed tomography or MRI at 3 to 6 months, 12 months, and then yearly; the interval of observation may be varied (eg, shorter intervals if the mass is enlarging); the duration of observation may be individualized. Observation may be considered for a solid renal mass of any size in a patient with a limited life expectancy or comorbidities that increase the risk of treatment, particularly when the mass is small."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "In general, large (>3cm) solid renal masses are likely malignant; similarly, the smaller a solid mass, the more likely it is benign. In addition, a small renal cell carcinoma is more likely to be low grade and indolent behaving than a larger one.Therefore we have suggested that solid masses <1cm be observed."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "This white paper which represents the collective experience of the Incidental Findings Committee, using a less formal process of repeated reviews and revisions of the draft document, does not represent official ACR policy. For these reasons, this white paper should not be used to establish the legal standard of care in any particular situation."

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • "The committee has used a consensus method based on repeated reviews and revisions of this document and a collective review and interpretation of relevant literature. This white paper provides guidance devloped by this committee for addressing incidental findings in the kidneys, liver , adrenal gland and pancreas"

    Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee
    Berland LL et al.
    J Am Coll Radiol 2010;7;754-773

  • Mesenchymal Renal Neoplasms: Malignant
    - Leiomyosarcoma
    - Rhabdomyosarcome
    - Angiosarcoma
    - Osteosarcoma
    - Synovial sarcoma
    - Fibrosarcoma
    - Malignant fibrous histiocytoma
    - Solitary fibrous tumor
  • Kidney: Transitional Cell Carcinoma of the Kidney: Facts
    - Multiplicity common

    - Distal ureter most common site in the ureter (73%)

    - metastases common to renal vein, IVC and local nodes

    - Tumors may occassionally have fine stippled calcifications

  • Kidney: Transitional Cell Carcinoma of the Kidney: Facts
    - 15% of malignant renal tumors

    - More common in men (2-1)

    - Incidences peaks in 7th decade

    - Upper tract TCC occurs in 2% of patient with lower tract disease, but 40% of patients with upper tract disease develop lower tract disease

     

  • "The hallmark of TCC is multiplicity and recurrence. Nearly 2-4% of patients with bladder cancer develop upper tract TCC, but 40% of patients with upper tract TCC develop bladder cancer."

    Imaging and Staging of Transitional Cell Carcinoma: Part 2, Upper Urinary Tract
    Vikram R et al
    AJR 2009;192:1488-1493

  • Renal Mass in 17 yr old African American female

    - Renal medullary carcinoma (if patient has sickle trait)
    - Rhabdoid tumor
    - Mesoblastic nephroma
    - Wilms’ tumor
    - Renal cell carcinoma, sarcomatoid variant
  • Solitary Renal Mass in a Older Child

    - Wilms’ tumor
    - Clear cell sarcoma of the kidney
    - Mesoblastic nephroma
    - Rhabdoid tumor
    - Renal cell carcinoma
    - Teratoma
    - Renal medullary carcinoma
  • Fibrous Tumor of the Kidney

    - Rare tumor (less tha 30 reported cases)
    - Immunohistochemically tumor cells are positive for CD34, CD99 and bcl-2.
    - Spindle cell neoplasm with hypervascular pattern like hemangiopericytoma like growth pattern
    - Prognosis usually favorable
  • Fibrous Tumor of the Kidney

    - Pre-op diagnosis usually renal cell carcinoma
    - Tumors usually in 8-12 cm range
    - Although these tumors are usually benign reports of malignant transformation have occurred
    - Looks similar to solitary fibrous tumor of the pleura (most common site for SFT)
  • WHO Histological Classification of Benign Renal Neoplasms

    - Renal cell tumors
    - Metanephric tumors
    - Mesenchymal tumors
    - Mixed epithelial and mesenchymal tumors
  • Renal Cell Tumors

    - Oncocytoma
    - Papillary adenoma
  • Metanephric Tumors

    - Metanephric adenoma
    - Metanephric adenofibroma
    - Metanephric stromal tumor
  • "High resolution images obtained with thin section MDCT can play an increasing role in the accurate detection and assessment of the upper urinary tract TCC."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • "High resolution images obtained with thin section MDCT can play an increasing role in the accurate detection and assessment of the upper urinary tract TCC.Local extension of tumors and location of the tumor relative to the kidney and adjacent organs are well shown on MPR and 3D images."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • "Local extension of tumors and location of the tumor relative to the kidney and adjacent organs are well shown on MPR and 3D images."

    Transitional Cell Neoplasm of the Upper Urinary Tract: Evaluation with MDCT
    Kawamoto S, Horton KM, Fishman EK
    AJR 2008; 191:416-422
  • Proportion of Solid Renal Masses That are Benign:

    Size (cm)Proportion
    All sizes12.8%
    0 to < 146.3%
    1 to < 222.4%
    2 to < 322.0%
    3 to < 419.9%
    4 to < 59.9%
    5 to < 613.0%
    6 to < 74.5%
    > 76.3%
  • Fact: small renal masses removed at surgery are often benign
    Solid Renal Tumors: An Analysis of Pathological Features Related to Tumor Size
    Frank I et al.
    J Urol 2003; 170:2217-2220
  • Genitourinary Lymphoma: CT Patterns of Involvement

    - 3-8% incidence of involvement
    - Kidney is the most common site of involvement
    - Renal metastases can mimic lymphoma
    - Bladder involvement can occur in up to 8% of patients
  • Renal Lymphoma: CT Patterns of Involvement

    - Multiple circumscribed masses
    - Direct infiltration from adjacent nodes
    - Solitary mass
    - Isolated perinephric mass
  • Renal Cell Carcinoma: Sites of Metastases

    - 25-30% have metastases at time of presentation
    - 20% have locally advanced disease at presentation
    - 50% of patients develop metastases even with nephrectomy for early stage disease
  • Perinephric Masses on CT: Differential Diagnosis

    - Lymphoma
    - Metastases (especially melanoma)
    - Myeloma
    - Urinomas
    - Hemmorrhage
    - Infection
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Erdheim Chester disease
  • "In the corticomedullary phase, attenuation values of renal clear cell carcinoma were significantly higher than those of renal papillary carcinoma. In renal clear cell carcinoma the mean attenuation value was 152.6 HU (range 90-256 HU); in renal papillary carcinoma, the value was 61.8 HU (range 38-123 HU)."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • "In the corticomedullary phase, attenuation values of renal clear cell carcinoma were significantly higher than those of renal papillary carcinoma. The accuracy was 95.7%; the sensitivity 98.3% and the specificity, 92% when using 100HU as the cutoff value."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • "In renal clear cell carcinoma, the mean nephrographic attenuation value was 105 HU (range 88-120HU); in renal papillary carcinoma it was 67.3 HU (range 38-88HU).The accuracy was 94.8%; the sensitivity 95.2%, qnd the specificity 92.3% when using 85 HU as the cutoff value."

    Differentiation of Renal Clear Cell Carcinoma and Renal Papillary Carcinoma Using Quantitative CT Enhancement Parameters
    Ruppert-Kohlmayr AJ et al.
    AJR 2004; 183:1387-1391
  • What is the importance of predicting papillary vs clear cell renal cell carcinoma?

    - Management decisions including partial vs classic nephrectomy
    - Open vs laprascopic procedure
    - Follow up if conservative management is chosen
  • "Certain imaging features and the degree of enhancement may be helpful in differentiating subtypes of renal cortical tumors."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Ninety percent of clear cell renal cell carcinomas (RCCs) are hypervascular and demonstrate a heterogeneous enhancing pattern of mixed enhancing solid soft tissue components and low attenuation necrotic or cystic areas."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Seventy-five percent of papillary renal cell carcinomas (RCCs) are hypovascular, and 90% of all papillary tumors demonstrate a homogeneous or peripheral enhancement pattern."

    Solid Renal Cortical Tumors: Differentiation with CT
    Zhang J et al.
    Radiology 2007; 244:494-504
  • "Caoili and associates reviewed the CT urographic appearance of pathologically proved transitional cell carcinoma of the renal collecting systems and ureters and correlated the findings from CT urography with those from pathologic examination. Twenty four (89%) of the 27 neoplasms could be identified at CT Urography."

    CT Urography: Technique and Applications
    Caoili EM, Cohan RH
    Categorical Course RSNA 2006; 11-22
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan seperated by 50 seconds. The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely."

    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan separated by 50 seconds."

    Differentiation of Renal Neoplasms From High Density Cysts: Use of Attenuation Changes Between the Corticomedullary and Nephrographic Phases of Computed Tomography
    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely." Differentiation of Renal Neoplasms From High Density Cysts: Use of Attenuation Changes Between the Corticomedullary and Nephrographic Phases of Computed Tomography
    Zagoria RJ et al.
    J Comput Assist Tomogr 2007;31:37-41
  • "Almost all renal neoplasms studied had an attenuation change of more than 10 HU, either increased or decreased, between the 2 phases of contrast-enhanced CT scan separated by 50 seconds. The results suggest that if the attenuation of a renal tumor changes by more than 10 HU between phases of a contrast enhanced CT, then the diagnosis of renal neoplasm is very likely."
  • Perinephric Mass: Differential Dx

    - Proliferative diseases
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Rosai-Dorfman disease
    - Erdheim-Chester disease
  • Perinephric Mass: Differential Dx

    - Tumors
    - Renal cell carcinoma
    - Lymphoma
    - Metastases (melanoma)
    - Retroperitoneal tumors by direct extension
  • Perinephric Mass: Differential Dx

    - Fluid
    - Hematoma
    - Urinoma
    - Abscess
    - Pancreatic pseudocyst
  • Perinephric Mass: Differential Dx

    - Tumors
    - Fluid
    - Inflammation
    - Proliferative diseases
  • Transitional Cell Carcinoma: Facts

    - Clinical presentation usually hematuria
    - Account for up to 10% or neoplasms of the kidney
    - Often multifocal
    - Age range is 60-70’s
  • Renal Cell Carcinoma: Facts

    - 85% of all renal cancers in adults
    - 30,000 new cases diagnosed in the US each year
    - M>F by 2-1
    - Peak incidence is age 50-70
    - Tumors are adenocarcinomas
  • Renal Cell Carcinoma: Risk Factors

    - Acquired cystic renal disease
    - Chronic renal failure
    - Von Hippel Lindau disease
    - Smoking
    - Hereditary renal cell carcinoma
  • von Hippel-Lindau Disease: Facts

    - Autosomal dominant familial tumor syndrome
    - High penetrance with variable expression
    - Prevalence of one in 50,000
    - Defect in short arm of chromosome 3
  • von Hippel-Lindau Disease: organ involvement

    - Kidney
    - Adrenal
    - Pancreas
    - Brain
    - Spinal cord
    - Retina
  • von Hippel-Lindau Disease: Renal Pathology

    - Renal cysts- occur in 50-75% of patients and are usually multiple and bilateral
    - Renal cell carcinoma-occur in 28-45% of patients and occur at a younger age (30-36 yrs). The lesions are often multiple and bilateral and may be hypovascular or cystic lesions with mural nodules
  • von Hippel-Lindau Disease: Adrenal Pathology

    - Pheochromocytoma
    - Occur in up to 30% of families with VHL
    - They are bilateral in up to 50% of patients with a malignancy rate of around 10%
    - Up to 18% are extraadrenal in location
  • von Hippel-Lindau Disease: Pancreatic Pathology

    - Occur in up to 77% of patients
    - Lesions include
    - Simple pancreatic cysts
    - Serous cystadenomas
    - Neuroendocrine tumors
    - Pancreatic carcinoma
  • von Hippel-Lindau Disease: Uncommon Pathology

    - Liver cysts
    - Cystadenomas of the epididymis and broad ligament
  • "In evaluating Robson stage I of renal cell carcinoma, we were able to diagnose fat infiltration on 1-mm scans with 96% sensitivity, 93% specificity, and 95% accuracy; the positive and negative predictive values were, respectively, 100% and 93%."

    High-Resolution Multidetector CT in the Preoperative Evaluation of Patients with Renal Cell Carcinoma
    Catalano C et al.
    AJR 2003; 180:1271-1277
© 1999-2021 Elliot K. Fishman, MD, FACR. All rights reserved.