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

Imaging Pearls ❯ Small Bowel ❯ Malignant Tumors

  
  • “Diagnosis is a challenge owing to nonspecific clinical manifestation, rare occurrence, and low index of clinical suspicion. Yet, various small bowel neoplasms have characteristic imaging features at CT and MRI when optimal distention of the small bowel is achieved, correlating well with features seen in gross specimens. Understanding the imaging features of small bowel neoplasms is important to improve the radiologist’s ability to diagnose and characterize small bowel neoplasms. Most small bowel tumors are clinically silent for long periods, and nearly half of the benign tumors are found incidentally during surgery or at cross-sectional imaging performed for other reasons.”
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • * Small bowel neoplasms are rare, accounting for 0.5% of all cancers and approximately 3% of all gastrointestinal tumors in the United States, and their incidence is rising—in particular, there is a rising incidence of small bowel carcinoid tumor.  CT enterography and MR enterography are optimal imaging studies for assessing for small bowel tumors.
    * Adenoma and gastrointestinal stromal tumor (GIST) are the most common benign small bowel tumors and the only two with malignant predisposition.
    * GIST may be indistinguishable from other mesenchymal tumors (eg, leiomyoma) at imaging. All GISTs are now con- sidered potentially malignant; therefore, surgical resection should be considered regardless of size.
    * The most frequent site of small bowel involvement with lym- phoma is the ileum owing to the presence of abundant lymphoid tissue.
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • "Peutz-Jeghers syndrome is a rare autosomal dominant inherited condition, although sporadic cases have been reported. It is less common than familial ad- enomatous polyposis and is characterized by multiple hamartomatous small bowel polyps, which are composed of smooth muscle and covered by normal mucosa. Peutz-Jeghers polyps are most often found in the jejunum followed by the ileum and duodenum.The condition is also characterized by mucocutaneous perioral and genital melanin pigmentation and increased risk of intestinal adenocarcinoma and nongastroin- testinal tumors.”
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • "The mean age of diagnosis is 65 years. Small bowel neoplasms demonstrate a higher prevalence in black patients than in white patients . Metastatic lesions of the small bowel from tumors such as melanoma, lung cancer, and breast cancer are more common than primary small bowel malignancy. Among all symptomatic small bowel tumors, malignant lesions are more prevalent than benign lesions. Malignant lesions have a poor prognosis and usually manifest late with subocclusive crisis when at least two-thirds of the bowel lumen is occluded. This is due to the tolerance of the small bowel to obstructive phenomena.”
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • “More common risk factors for malignant small bowel tumors include chronic inflammation; inherited conditions such as familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer (HNPCC), and Peutz-Jeghers syndrome; and infections such as human immunodeficiency virus (HIV). Small bowel malignant lesions metastasize frequently owing to the rich portal drainage. Curative surgical resection is the goal of treatment of most small bowel tumors with the exception of early localized lymphoma, for which other nonsurgical treatments have become more refined. Radiation therapy and chemotherapy are usually retained for more advanced stage III or IV disease.”
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • "Small bowel adenocarcinoma represents 25%– 40% of primary malignant small bowel tumors. It arises from the glandular epithelium. Predisposing conditions include polyposis syn- dromes, celiac disease, and Crohn disease. The median age of onset is 50–70 years. Primary adenocarcinoma most commonly occurs in the proximal jejunum or distal duodenum. Patients can present with vague symptoms including abdominal pain, nausea, vomiting, weight loss, gastrointestinal bleeding, anemia, and jaundice.”
    Small Bowel Neoplasms: A Pictorial Review
    Jasti R, Carucci LR
    RadioGraphics 2020;40:1020-1038
  • “Schwannomas are benign nerve sheath tumors with significant Schwann cell differentiation. They similarly affect both genders and are atypically discovered in patients in their 3th and 5th decades of life. Schwannomas most commonly involve peripheral, motor, sympathetic, or cranial nerves of the head and neck region and upper and lower extremities. Schwannomas have been found at almost every location of the body including in extremities, head, neck, retroperitoneum, mediastinum, pelvis, and rectum. Visceral locations, however, are very rare and preoperative diagnosis is challenging, as schwannomas are often confused with other neoplasms. We review the imaging findings of abdominal schwannomas focusing on pancreatic, gastrointestinal, and retroperitoneal/adrenal schwannomas.”
    Abdominal schwannomas: review of imaging findings and pathology. 
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5
  • “The most common locations of cellular schwannomas are the paravertebral areas in pelvis, retroperitoneum, and mediastinum. On imaging, the more vascular Antoni A areas are usually enhancing solid components, whereas Antoni B areas are frequently nonenhancing cystic or multiseptated components. Immunohistochemical labeling is a usually required for accurate diagnosis. S-100 protein positivity is an important marker in the diagnosis of schwannoma, as the neoplastic cells strongly label with antibodies to S-100.”
    Abdominal schwannomas: review of imaging findings and pathology. 
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5
  • “On computed tomography (CT) or magnetic resonance imaging (MRI), schwannomas in various anatomic locations are typically a well-demarcated round or oval masses. Calcification and cystic changes may be seen in larger tumors. After contrast enhancement, homogeneous to heterogeneous contrast enhancement may be seen due to variable degree of internal cystic and hemorrhagic changes. Most schwannomas appear as inhomogeneous low-density masses on CT scan images, isointense with muscle on T1-weighted images, and high intensity on T2-weighted images on MRI.”
    Abdominal schwannomas: review of imaging findings and pathology. 
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5
  • “Schwannomas rarely arise in the gastrointestinal tract. When they do, they are most often seen in the stomach followed by in small intestine and in colon or the rectum. In addition to the typical histological features of schwannomas, schwannomas of the gastrointestinal tract often have a peripheral cuff of lymphoid cells. Additionally, distinct Antoni A (Verocay bodies) and B areas are usually not present. Schwannomas of the gastrointestinal tract are usually submucosal and richly vascular. The lesions typically protrude into the lumen of the bowel and can be associated with small mucosal erosions, which can be appreciated at endoscopic examination. Because they are submucosal, superficial biopsies may be negative. Most schwannomas of the gastrointestinal tract grow contralateral to the mesenteric attachment. They are usually clinically indolent but can erode the overlying mucosa, causing complications such as bleeding or bowel obstruction.”
    Abdominal schwannomas: review of imaging findings and pathology. 
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5
  • "Gastrointestinal schwannomas are similar to gastrointestinal stromal tumors (GISTs) on CT or MRI. However, it has been suggested that compared to GISTs, schwannomas tend to be more homogeneously enhancing, more often exophytic or mixed (both endoluminal and exophytic), and slower growing. Homogeneous attenuation may be due to small tumor size and lack of hemorrhage, necrotic, or cystic degeneration. Immunohistochemical labeling is often necessary to confirm the diagnosis. Virtually all GISTs express c-Kit and DOG1, whereas schwannomas are negative for c-Kit and DOG1, and strongly express S100.”
    Abdominal schwannomas: review of imaging findings and pathology.
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5
  • "Abdominal Schwannoma is rare and preoperative diagnosis is challenging because of the lack of definitive non-histological diagnostic modalities, as imaging findings are not specific even with developed advanced imaging techniques. Surgical excision is required for treatment and to provide a definitive diagnosis made by histological and immunohistochemical evaluations. Understanding the image findings of abdominal schwannomas will help with considering schwannoma in differential diagnosis appropriately to guide treatment plan and to avoid an unnecessary radical resection.”
    Abdominal schwannomas: review of imaging findings and pathology.
    Lee, N.J., Hruban, R.H. & Fishman, E.K.
    Abdom Radiol 42, 1864–1870 (2017). https://doi.org/10.1007/s00261-017-1088-5 
  • “B cell lymphoma, especially diffuse large B-cell lymphoma (DLBL), is the most common type of primary gastrointestinal lymphoma, of which primary non-Hodgkin lymphoma (NHL) of gastrointestinal tract accounts for 10–15% of NHLs; the most commonly involved site of DLBL is the ileum of the small bowel. T-cell lymphoma, which occurs much less frequently than B-cell lymphoma, tends to develop in the proximal portion of the small bowel, such as the jejunum or proximal ileum.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • “Perforation is observed in 16–33% of patients with T-cell lymphoma at the time of clinical presentation, and this is attributed to transmural involvement and necrosis. Additionally, T-cell lymphoma is more likely to be multifocal disease than is B-cell lymphoma. In patients with celiac disease, there is an increased incidence of T-cell lymphoma in the small bowel, especially jejunum.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • Some nonneoplastic diseases that occur in the proximal portion of the small bowel occasionally appear as focal wall thickening and may require differentiation from tumorous conditions. Eosinophilic gastroenteritis, characterized by eosinophilic infiltration of the stomach and proximal small bowel, appears as nodular and irregular fold thickening; therefore, it can mimic the appearance of lymphoma or small bowel adenocarcinoma. In addition, giardia- sis and Whipple’s disease present as thickened folds in the distal duodenum and proximal jejunum. Although rare, localized lymphangiectasia of the jejunum resulting from lymphatic blockage of a limited bowel segment may mimic the appearance of lymphoma on CT, as low-attenuating wall thickening of the small bowel
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345

  • Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • “Melanoma accounts for about one-third of all metastases involving the gastrointestinal tract. In a study of 32 patients with small bowel metastases from melanoma, a polypoid pattern with equal distribution between the jejunum and ileum, was found in 20 patients (63%); in addition, approximately 19% of patients showed polyposis (more than 10 masses). The average lag time from the initial diagnosis of melanoma to the detection of small bowel metastases was reported to be 3.2 years.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • “Neuroendocrine tumors occur most commonly in the small bowel, especially the distal ileum; 40% of them are found within 60 cm of the ileocecal valve. Arterial phase CT scanning is useful for the detection of small bowel neuroendocrine tumors, because the tumors usually present with small hyperenhancing masses (30% of these are multiple at diagnosis). Neuroendocrine tumor cells tend to show infiltrative growth through the small bowel wall into the adjacent mesentery, causing mes- enteric fibrosis with the encasement of mesenteric vessels that subsequently results in bowel ischemia. If the primary tumor is larger than 2 cm, nodal metastasis and liver metastasis occur in more than 80% and 40% of tumors, respectively.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • Hypervascular masses in the small bowel: Differential Dx
    - hemangiomas
    - small GISTs
    - neuroendocrine tumors
    - malignant gastrointestinal neuroectodermal tumors (GNETs)
    - metastases of hypervascular primary cancer
  • Purpose To evaluate the feasibility of using computed tomography texture analysis (CTTA) parameters for predicting malignant risk grade and mitosis index of gastrointestinal stromal tumors (GISTs), compared with visual inspection.
    Conclusion Using TexRAD, MPP and kurtosis are feasible in predicting risk grade and mitosis index of GISTs. CTTA demonstrated meaningful accuracy in preoperative risk stratification of GISTs.
    Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection
    Choi IY et al.
    Abdominal Radiology (2019) 44:2346–2356
  • “In the NCCN guideline, if the size of the tumor is more than 10 cm or the mitosis count is more than 5 in high- power fields (HPFs), the gastric GIST is classified as a high risk. For tumors in the small and large intestines, if the tumor size exceeds 5 cm, or the mitosis count is more than 5 in 50 HPFs, the tumor is classified as a high risk.”
    Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection
    Choi IY et al.
    Abdominal Radiology (2019) 44:2346–2356
  • “Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. About 10–30% of GISTs are clinically malignant, but all GISTs are considered to have some degree of malignant potential. The malignancy risk of GISTs is deter- mined based on the mitotic index, tumor size, and site of the lesion according to National Comprehensive Cancer Network (NCCN) guidelines.”
    Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection
    Choi IY et al.
    Abdominal Radiology (2019) 44:2346–2356
  • “In conclusions, CTTA parameters, such as MPP and kurtosis can be useful in predict the risk grade and mitosis index of GISTs. In our study, texture analysis parameters demonstrated meaningful accuracy in preoperative diagnosis of tumor risk stratification and can be used as imaging biomarkers for determination of tumor grade.”
    Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection
    Choi IY et al.
    Abdominal Radiology (2019) 44:2346–2356
  • “Except for adenoma, adenocarcinoma, and neuroendocrine tumor that arise from the epithelial layer, most tumors originating from the small bowel develop in the submucosal layer, including lymphoma, lipoma, hemangioma, inflammatory fibroid polyp, and malignant gastrointestinal neuroectodermal tumor. In addition, gastrointestinal stromal tumor originates from the muscularis propria. Metastasis can involve the various layers of the small bowel according to spreading mechanism.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Sang Won Kim et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01978-5
  • Small Bowel Adenocarcinoma: Increased Risk Factors
    - familial adenomatous polyposis
    - Lynch syndrome
    - Peutz-Jeghers syndrome
    - Crohn’s disease
    - celiac disease
    - alcohol consumption and
    - smoking
  • “T-cell lymphoma, which occurs much less frequently than B-cell lymphoma, tends to develop in the proximal portion of the small bowel, such as the jejunum or proximal ileum. Perforation is observed in 16–33% of patients with T-cell lymphoma at the time of clinical presentation, and this is attributed to transmural involvement and necrosis. Additionally, T-cell lymphoma is more likely to be multifocal disease than is B-cell lymphoma.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Sang Won Kim et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01978-5
  • “B cell lymphoma, especially diffuse large B-cell lymphoma (DLBL), is the most common type of primary gas- trointestinal lymphoma, of which primary non-Hodgkin lymphoma (NHL) of gastrointestinal tract accounts for 10–15% of NHLs; the most commonly involved site of DLBL is the ileum of the small bowel.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Sang Won Kim et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01978-5
  • Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Sang Won Kim et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01978-5
  • “Although the small intestine accounts for over 90% of the surface area of the alimentary tract, tumors of the small intestine represent less than 5% of all gastrointestinal tract neoplasms. Common small bowel tumors typically are well evaluated with cross-sectional imaging modalities such as CT and MR, but accurate identification and differentiation can be challenging. Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique. While endoscopic evaluation is typically more sensitive for the detection of intraluminal tumors that can be reached, CT and MR, as well as select nuclear medicine studies, remain superior for evaluating extraluminal neoplasms. Understanding the imaging characteristics of typical benign and malignant small bowel tumors is critical, because of overlapping features and associated secondary complications.”
    Multimodality imaging of small bowel neoplasms.
    Williams EA1, Bowman AW2
    Abdom Radiol (NY). 2019 (in press)
  • “Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders. Gastrointestinal manifestations of NF-1 are seldom thought of in routine clinical practice and might thus be significantly under-recognized. Their heterogeneous spectrum ranges from localized microscopic proliferative lesions to grossly recognizable mass-forming neurofibromas, neuroendocrine and gastrointestinal stromal tumours (GIST).”
    Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review
    Garrouche N et al.
    Insights into Imaging
    https://doi.org/10.1007/s13244-018-0648-8
  • “Neurofibromatosis type 1 (NF1) or Recklinghausen disease is a tumour syndrome caused by alterations in the NF-1 gene . It belongs to a group of disorders referred to as phakomatoses or neurocutaneous syndromes, including neurofibromatosis (type 1 and type2 ), tuberous sclerosis (Bourneville-Pringle disease), Von Hippel-Lindau (VHL) disease, Sturge-Weber syndrome (SWS) and many other neurocutaneous diseases (ataxia telangiectasia, incontinentia pigmenti, etc.”
    Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review
    Garrouche N et al.
    Insights into Imaging
    https://doi.org/10.1007/s13244-018-0648-8
  • “Gastrointestinal tract neoplasms in NF-1 patients are more frequent than in the general population and occur in three main forms: hyperplasia of the submucosal and myenteric nerve plexuses and mucosal ganglioneuromatosis that leads to disordered gut motility; gastrointestinal stromal tumours (GIST) with varying degrees of neural or smooth muscle differentiation; distinctive glandular somatostatine-rich carcinoid in the periampullary region of the duodenum, which contains psammoma bodies and may be associated with pheochromocytoma. “
    Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review
    Garrouche N et al.
    Insights into Imaging
    https://doi.org/10.1007/s13244-018-0648-8
  • “Bakker and al examined 61 reported cases of non- carcinoid gastrointestinal (GI) neoplasms in patients with NF-1. Neoplasms were located most often in the small intestine (72%). Neurofibromas (52%) were the most frequently diagnosed benign neoplasms followed by leiomyomas (13%), ganglioneurofibromas (9.8%) and gastrointestinal stomal tumour (GIST) (6.5%). Malignant tumour adenocarcinoma accounted for 23% in this review.”
    Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review
    Garrouche N et al.
    Insights into Imaging
    https://doi.org/10.1007/s13244-018-0648-8
  • Gastrointestinal stromal tumour (GIST) is a mesenchymal tumour that represents the most common gastrointestinal manifestation of NF-1. It is reported in 5–25% of NF1 patients and accounts for 1.5% of all GISTs. GISTs associated with NF1 syndrome seem to have a distinct phenotype compared with sporadic GISTs: they occur in younger patients (mean age, 49 years versus 56 in sporadic GISTs), are multiple in 60% or develop in multiples sites, are smaller in size with low mitotic activity, follow a benign clinical course and occur mostly in the duodenum or small intestine. They are usually clinically asymptomatic and detected as incidental findings.
    Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review
    Garrouche N et al.
    Insights into Imaging
    https://doi.org/10.1007/s13244-018-0648-8
  • Neurofibromatosis and the GI Tract
    - Neurofibromatosis type (NF-1) is one of the most common single gene disorders.
    - Every organ system can be involved and intra-abdominal manifestations are underestimated.
    - The NF1 abdominal manifestations comprehend five categories of tumours.
    - Neurogenic tumours including with neurofibromas are the most common type.
    - Early diagnosis of abdominal manifestations of NF-1 based on imaging patterns is necessary for appropriate treatment to avoid
    - serious organic complications related to tumour mass.
  • “Small bowel adenocarcinomas are rare malignant tumors that account for less than 2% of gastrointestinal tumors. Among malignant tumors of the small bowel (SB), adenocarcinoma is the most frequent etiology in France followed by endocrine tumors, lymphomas or stromal tumors . Recent trends show that SB neuroendocrine tumors outnumber SB adenocarcinoma in the US .Epidemiological data estimate the annual incidence of small bowel adenocarcinoma at 2.2–5.7/million in developed countries. In the French Côte d'Or study, the incidence of small bowel adenocarcinoma was 0.18/100,000 men and 0.1/100,000 women during the period 1996–2001, and which incidence increased with age. However, and as is the case for colon cancer, the incidence of small bowel adenocarcinoma is increasing in the population. Moreover, duodenal tumors are more frequent than tumors in other segments (jejunum and ileum).”


    Small bowel adenocarcinoma: French intergroup clinical practice guidelines for diagnosis, treatments and follow-up 
Christophe Locher et al.
Digestive and Liver Disease (in press)
  • “Indeed, duodenal tumors account for 50% of small bowel adenocarcinomas while tumors of the jejunum and ileum represent 30% and 20%, respectively . The stage at diagnosis is usually advanced; in the series of Talamonti et al., 38% of the patients had synchronous metastases and 38% had lymph-node invasion . In the MD Anderson study, the same distribution by stage was found (35% of metastatic patients and 39% with lymph-node invasion).”

    
Small bowel adenocarcinoma: French intergroup clinical practice guidelines for diagnosis, treatments and follow-up 
Christophe Locher et al.
Digestive and Liver Disease (in press)
  • “In celiac disease, the risk of developing small bowel adenocarcinoma is low (8 cases per 11,000 patients for the Swedish registry). Duodenal biopsies during the initial endoscopy and an anti-transglutaminase (IgA) or anti-transglutaminase (IgG) and anti-endomysium (IgG) antibody assay in cases of IgA deficiency are recommended.”


    Small bowel adenocarcinoma: French intergroup clinical practice guidelines for diagnosis, treatments and follow-up 
Christophe Locher et al.
Digestive and Liver Disease (in press)
  • “The relative risk of developing small bowel adenocarcinoma in Crohn’s disease is about 20. In Crohn’s disease, the preferred location is the ileum and the age at onset is younger (4th decade) . If there is a family history of Crohn’s disease or if there are clinical symptoms, a morphological examination of the small bowel and a proctologic examination are recommended.”


    Small bowel adenocarcinoma: French intergroup clinical practice guidelines for diagnosis, treatments and follow-up 
Christophe Locher et al.
Digestive and Liver Disease (in press)
  • “Small bowel cancers are very rare despite the length and large mucosal surface of the small bowel and account for 3% to 6% of all gastroin- testinal (GI) tract malignancies. Adenocarcinoma, neuroendocrine neoplasms, lymphoma, and GI stromal tumors (GISTs) are the most prevalent primary small bowel cancers, with adenocarcinoma and neuroendocrine neoplasms accounting for nearly two-thirds of small bowel cancers.”

    
Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “Capsule endoscopy is a safe and minimally invasive modality for visualizing the entire small bowel. It is typically well tolerated by patients. The limitations of the procedure include diagnostic procedure (no therapeutic ability), potential of missing a lesion, decreased visualization if fluid or bubbles are retained in the lumen, false- positive findings, and capsule retention if stricture or significant inflammation present.”

    
Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “There are mixed results for capsule endoscopy in the detection of small bowel tumors. In small retrospective and prospective single-center studies, CT enterography was shown to be superior to capsule endoscopy in the detection of small bowel tumors.”


    Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “Several hereditary conditions, including familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer (also known as Lynch syndrome), Peutz- Jeghers syndrome, MUTYH-associated polyposis, and cystic fibrosis, are well known to be associated with increased risk for small bowel adenocarcinoma. .”

    
Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “The most typical appearance of small bowel adenocarcinoma is an annular, constricting mass (apple-core lesion) that causes luminal narrowing that is often associated with upstream bowel dilatation. Even a small encircling adenocarcinoma can cause small bowel obstruction due to prominent intratumoral desmoplasia, and a small obstructing cancer should not 
 be neglected.”

    
Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “A variety of conditions increase the risk of small bowel GISTs. Familial GIST is autosomal dominant and often leads to the development of a single or multiple GISTs in middle age. Additionally, about 5% of patients with neurofibromatosis type 1 (NF-1) will present with a small bowel GIST; GISTs can be seen in young females as part of the Carney triad (gastric or small bowel GIST, pulmonary chondroma, and extra-adrenal pheochromocytoma) or in males or females as part of the Carney-Stratakis syndrome (GIST and paraganglioma).”

    
Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “Neuro- endocrine neoplasms typically occur in distal/terminal ileum, with the small bowel primary presenting as a small enhancing polyp or more 
characteristically as a plaquelike mass, often with serosal retraction. Tumor can be singular or multifocal along a bowel segment. Nodal metastases typically cluster around mesenteric vessels (with potential to narrow or occlude them), with advanced mesenteric metastases presenting with a characteristic pattern of rounded soft tissue, punctate calcification, and radiating strands of desmoplasia.”


    Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • “Crohn disease can mimic small bowel tumors; patients with long-standing Crohn disease are at increased risk for these tumors, particularly lymphoma and adenocarcinoma, which can be discovered incidentally. Radiological diagnosis of small bowel tumors developing in Crohn disease is very difficult because the imaging findings are similar to the findings of long- standing Crohn disease, and biopsy should be used when required to distinguish between them.”


    Imaging and Screening of Cancer of the Small Bowel 
Jin Sil Kim et al.
 Radiol Clin N Am (2017) (in press)
  • Treatment
    • Surgical resection is mainstay therapy for isolated small tumors without evidence of metastatic disease.
    • Laparoscopic resection may be attempted for small tumors with open procedures reserved for larger tumors.
    • Imatinib mesylate, a tyrosine kinase inhibitor, is first line therapy for patients who are poor surgical candidates, or show evidence of recurrence or metastatic disease.
    • Can also be used as neoadjuvant therapy to preoperatively shrink large tumors
  • Imaging Surveillance
    • Surveillance after surgery includes CT scanning with contrast every 3 to 6 months.
    • Low grade small tumor may have scans every 6 to 12 months.
    • Patients receiving imatinib mesylate therapy may have scans every 3 months.
    • Dual phase imaging is recommended as arterial phase may detect new enhancing components in stable disease that may wash out during venous phase and be overlooked.
  • Small Bowel Carcinoid Tumors: Facts
    • Second most common small bowel malignancy. 
    • Rarely presents with carcinoid syndrome (watery diarrhea, flushing and endocardial fibrosis) when disease spreads to the liver
    • Appendix most common site followed by ileum
    • Avidly enhancing polypoid mass.
    • Primary tumor usually small.
    • Tumor spread with calcified mesenteric mass with desmoplastic response and tethering of adjacent small bowel loops.
    • Liver metastasis usually hypervascular
  • “For both GIST and NET, the mean attenuation values of the tumors were significantly higher than those of adenocarcinoma and lymphoma in both the arterial and enteric phases (all p-values < 0.05). The mean attenuation value of GIST was significantly higher than that of metastases in both the arterial (p = 0.041) and enteric phases (p = 0.000199). The mean attenuation value of NET was significantly higher than that of metastases in the enteric phase (p = 0.000199).”


    Small bowel neoplasms: enhancement patterns and differentiation using post-contrast multiphasic multidetector CT
 Shinya, T., Inai, R., Tanaka, T. et al. 
Abdom Radiol (2017) 42: 794. doi:10.1007/s00261-016-0945-y 

  • “The use of multiphasic threshold levels led to an improvement in diagnostic accuracy; GIST could be discriminated from adenocarcinoma with an accuracy of 82.76%, GIST could be discriminated from lymphoma with an accuracy of 87.50%, and NET from adenocarcinoma with an accuracy of 92.00%.”


    Small bowel neoplasms: enhancement patterns and differentiation using post-contrast multiphasic multidetector CT
 Shinya, T., Inai, R., Tanaka, T. et al. 
Abdom Radiol (2017) 42: 794. doi:10.1007/s00261-016-0945-y 

  • “In conclusion, the mean CT attenuation values could potentially be useful to discriminate between the small bowel neoplasms with acceptable diagnostic capacities, using individual monophasic and multiphasic threshold levels on post-contrast multiphasic MDCT, particularly in the arterial phase, for the four primary small bowel neoplasms in this study. The results of our study suggest that there may be a consistent relationship between the enhancement pattern on post-contrast multiphasic MDCT and the histologic findings and that the multiphasic dynamic enhancement data could be a robust tool for the discrimination of small bowel neoplasms.”


    Small bowel neoplasms: enhancement patterns and differentiation using post-contrast multiphasic multidetector CT
 Shinya, T., Inai, R., Tanaka, T. et al. 
Abdom Radiol (2017) 42: 794. doi:10.1007/s00261-016-0945-y
  • “The duodenum can be involved in several major polyposis syndromes, including familial adenomatous polyposis (FAP), Peutz Jeghers syndrome, Cronkite Canada syndrome, and juvenile polyposis. Duodenal polyps are commonly found in patients with Cronkite Canada syndrome, which shows similarities to juvenile polyposis, but polyps are usually small and more diffuse. Ectodermal changes, such as alopecia and nail dystrophy; and inflammatory infiltrate in lamina propria are associated with Cronkite Canada syndrome. Polyps associated with Cronkite Canada syndrome are more commonly sessile than pedunculated.”

    
Imaging Spectrum of Non-neoplastic Duodenal Diseases
Sitthipong S et al.
Clinical Imaging (in press)
  • “Small bowel cancer is a rare malignancy that comprises less than 5 % of all gastrointestinal malignancies. The estimated annual incidence is 0.3–2.0 cases per 100,000 persons, with a higher prevalence rates in the black population than the white, and has been recently increasing. It is most frequently diagnosed among people aged 55–64, with the incidence increasing after age 40. The current 5-year survival rate in the USA is 65.5 %; cancer stage at diagnosis has a strong influence on the length of survival.”


    Small bowel adenocarcinoma of the jejunum: a case report and literature review
    Li J et al.
World Journal of Surgical Oncology201614:177
  • “Small bowel cancer has four common histological types: adenocarcinoma (30–40 %), carcinoid tumour (35–42 %), lymphoma (15–20 %), and sarcoma (10–15 %). Adenocarcinoma of the small bowel (SBA) is most commonly located in the duodenum (57 %), while 29 % of cases are located in the jejunum and 10 % in the ileum. Clinical presentation of SBA is nonspecific abdominal discomfort, such as abdominal pain, nausea, vomiting, gastrointestinal bleeding and intestinal obstruction, which leads to an average delay of 6–10 months in diagnosis.”


    Small bowel adenocarcinoma of the jejunum: a case report and literature review
    Li J et al.
World Journal of Surgical Oncology201614:177
  • “Whereas the small bowel represents 75 % of the length of the digestive tract and 90 % of the absorptive mucosal surface area, tumour of the small bowel is rarer than other gastrointestinal malignancies. The possible explanations include the high levels of IgA and the more rapid transit in the small bowel compared to the large bowel. Little bacteria and more sensitivity to stress in the small bowel also contribute to the low tumour incidence.”


    Small bowel adenocarcinoma of the jejunum: a case report and literature review
    Li J et al.
World Journal of Surgical Oncology201614:177
  • “Surgical resection with clear margins and regional lymph node resection remains the treatment of choice in localized SBA; indeed, it is often required even in metastatic SBA due to the high probability of obstruction or severe haemorrhage. To date, there has been no standard chemotherapy regimen against SBA. Several studies have explored the role of palliative chemotherapy in advanced SBA. Hong et al.have shown in stage IV patients who received palliative chemotherapy that overall survival (OS) increased significantly compared to those who did not receive chemotherapy (8 vs. 3 months, p = 0.025). Ecker et al. have shown that median OS was superior for patients with resected stage III SBA who were receiving chemotherapy versus those who were not (42.4 vs 26.1 months, p < 0.001).”


    Small bowel adenocarcinoma of the jejunum: a case report and literature review
Li J et al.
World Journal of Surgical Oncology201614:177
  • Small Bowel Cancer Facts
  • Common Cancer Numbers
  • Small Bowel Cancer: By The Numbers
  • “Metastases from colon cancer, ovarian carcinoma, breast cancer, lung cancer, carcinoid, and melanoma can spread to mesenteric lymph nodes. However, the degree of nodal enlargement seen in mesenteric metastatic disease is less pronounced than that seen in mesenteric lymphoma, and the distribution of in- volved nodes is comparatively more localized in metastatic disease”

    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheila Sheth, MD Karen M. Horton, MD Melissa R. Garland, MS   Elliot K. Fishman
    RadioGraphics 2003; 23:457– 473
  • “Tumors originating in the abdomen or elsewhere in the body can disseminate to the mesentery in four major ways: (a) direct spread along the mesenteric vessels and surrounding fat, (b) extension via the mesenteric lymphatics, (c) embolic hematogenous spread, and (d) intra- peritoneal seeding. Although convenient, this classification is somewhat arbitrary, since many neoplasms spread by more than one route.”

    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheila Sheth, MD Karen M. Horton, MD Melissa R. Garland, MS   Elliot K. Fishman
    RadioGraphics 2003; 23:457– 473  
  • Mesenteric Masses: Pathways
    (a) direct extension, commonly seen with carcinoid tumor of the small intestine as well as intraabdominal cancers such as pancreatic and colon cancer; 
    (b) lymphatic dissemination of lymphoma and some epithelial malignancies; 
    (c) hematogenic spread resulting in embolic metastases to the small intestinal wall, usually seen in melanoma and breast cancer; 
    (d) seeding through the peritoneum from ovarian and gastrointestinal malignancies as well as some lymphomas.
  • Primary Mesenteric Neoplasms
    - Desmoid tumor
    - Carcinoid Tumor
    - Sclerosing Mesenteritis
    - Lymphoma
    - Metastases
  • Round Well Defined Mesenteric Masses: Differential Diagnosis
    - Non-Hodgkin lymphoma 
    - Metastases
    - M avium–intracellulare 
    - tuberculosis
    - Whipple disease 
    - Mesenteric cyst
    - Mesenteric lipoma 
    - Castleman disease 
  • Ill Defined Mesenteric Masses: Differential Diagnosis
    - Small bowel carcinoid 
    - Mesenteric desmoid 
    - Tumor infiltration from pancreatic, gastric, or colon cancer 
    Lymphoma
    - Sclerosing mesenteritis 
  • Stellate Mesenteric Masses: Differential Diagnosis
    - Sclerosing mesenteritis 
    - Carcinomatosis; pancreatic, gastrointestinal, ovarian, or breast or colon cancer
    - Peritoneal lymphomatosis 
    - Malignant peritoneal mesothelioma
    - Peritoneal tuberculosis 
    - Systemic amyloidosis 
    - Vascular thrombosis 
  • "Duodenal carcinoid tumors commonly appear as an enhancing mass in either the arterial or venous phases. If a primary tumor is not seen in the duodenum, adjacent enhancing lymphadenopathy can be a clue to the presence of a duodenal carcinoid tumor."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • "On CT, 19 patients (67.8%) had neuroendocrine tumors manifested as polypoid or intraluminal masses (38 lesions, multiple tumors in 3 patients), 4 patients (14.3%) had tumors manifested as wall thickening or intramural masses, and in 5 patients (17.9%), the primary tumor was not visualized. Lesions not seen at CT were less than 0.8 cm on pathologic diagnosis. The mean size of polypoid tumors on CT was 1.2 cm (range 0.3-3.8 cm); 24 tumors were 1.0 cm or smaller, and 14 tumors were larger than 1.0 cm."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • "Most lesions were hypervascular in the arterial phase (19/23 patients) with an increase in tumor enhancement in the venous phase in 14 patients (60.9%), decrease in enhancement in 7 patients (30.4%), and no change in enhancement in 2 patients (8.7%). Thirteen patients (46.4%) had metastatic disease from carcinoid tumor, most commonly regional enhancing lymphadenopathy."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • "Gastrointestinal (GI) neuroendocrine tumors are submucosal masses with differentiation in the direction of neuroendocrine cells of the GI tract and comprise 1.2-1.5% of all GI tract neoplasms . Neuroendocrine cells are located throughout the body with two-thirds of neuroendocrine tumors arising in the GI tract, 25% in the lungs, and the remaining 10% in other sites in the body ."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • "Most duodenal carcinoids are sporadic but may be associated with clinical syndromes such as multiple endocrine neoplasia type 1 (MEN-1) and neurofibromatosis type 1(NF-1) . Two-thirds of duodenal neuroendocrine tumors are gastrinomas and one-third of these are functioning tumors manifesting as Zollinger-Ellison syndrome (ZES). The next most common type (20%) of duodenal neuroendocrine tumors is somatostatinomas."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • "Of the neuroendocrine tumors visualized at CT (either as polypoid intraluminal masses or wall thickening and intramural masses), the tumor was located in the second portion of the duodenum in 14 patients (60.9%), in the duodenal bulb in 4 patients (17.4%), and in the third portion of the duodenum in 2 patients (8.7%). Of the 14 patients whose tumors were located in the second portion of the duodenum, 10 (43.5%) had tumors in the peri-ampullary region; two of these patients had NF-1."

    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • “The duodenal GISTs were solitary masses with well-defined margins. The average diameter was 7.1 cm. The second portion was the most common site (20/34). Ulceration was a common feature (15/34). Calcification was uncommon (3/34), and mixed growth pattern was more common (26/34). Rim enhancement (24/34) and mixed enhancement pattern (15/34) were common. Arterial blood supply, intratumoral vasculature, and draining veins were all detected and were obvious on the arterial phase. The portal venous trunk and superior mesenteric vein were the main veins into which early arterioportal shunting drained.”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “Primary duodenal GISTs are generally large, well-defined, heterogeneously enhancing, and hypervascular masses with a prominent mixed growth pattern on CT images. Our findings suggest that CT can help depict the origin of the tumoral arteries and draining veins on the arterial phase and may be a key defining diagnostic feature for duodenal GISTs.”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “Almost all GISTs express active KIT receptor tyrosine kinase (CD117) mutants, which are crucial for the diagnosis of GISTs. The constitutive expression of CD117 in GISTs also distinguishes them from other mesenchymal neoplasms, such as leiomyomas, leiomyosarcomas, schwanno- 
mas, and neurofibromas.”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “GISTs can arise anywhere in the gastro- 
intestinal tract, most commonly in the stom- ach (60–70%) followed by the small bowel (20–25%). GISTs in the duodenum are rare (less than 5%).”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “All of the cases were solitary masses. The average diameter of the masses was 7.1 cm (range, 1.8–13.4 cm). Among the four portions of duodenum, the largest mean diameter of masses (9.8 cm; range, 6.6–13.4 cm) was located in the fourth portion and the smallest (2.3 cm; range, 1.8–2.8 cm) in the first portion.”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “The mean tumor attenuation in the most strongly enhanced portion in arterial, portal venous, and delayed phases was 118 HU (range, 63–180 HU), 106 HU (range, 60–145 HU), and 94 HU (range, 60–125 HU), respectively. Rim enhancement (24/34, which was obvious in the arterial phase) and mixed enhancement patterns (15/34) were common.”
    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • “In conclusion, primary duodenal GISTs are generally large, well-defined, heterogeneously enhancing, and hypervascular masses with a prominent mixed growth pattern on CT images. Our findings suggest that CT can help depict the origin of the tumoral arteries and draining veins in the arterial phase, which may be a key in defining diagnostic features for duodenal GISTs.”

    CT Characterization of Duodenal Gastrointestinal Stromal Tumors.
Cai PQ et al.
AJR Am J Roentgenol. 2015 May;204(5):988-93
  • Duodenal GIST Tumors: Differential Dx
    - Duodenal adenocarcinoma
    - Lymphoma
    - Pancreatic head adencarcinoma
  • “Many risk factors for primary GI lymphoma have been described, including celiac disease, human immunodeficiency virus infection/acquired immunodeficiency syndrome, ulcerative colitis, Crohn's disease, and immunosuppression following solid organ transplantation. Patients with celiac disease have a 200-fold increased risk of developing intestinal lymphoma, particularly enteropathy-associated T-cell lymphoma, which has an extremely poor prognosis with a median survival time of 4 months.”

    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65.
  • “The small bowel represents the second most common site of primary GI lymphoma, comprising approximately 24%-26%. Compared with primary GI lymphoma of the stomach, which tends to be of lower grade, small-bowel lymphomas are diagnosed at higher grades.”

    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65. 
  • “Although the ileum is most often affected by B-cell lymphomas presumably based on the relative abundance of lymphatic tissue, the jejunum appears to be more often involved in uncommon but more aggressive T-cell lymphomas. Lymphoma often affects multiple sites of small bowel with a roughly equal likelihood of affecting the same segment or different segments.Over 77% of lymphoma exceeds 5 cm in diameter, and the average length of affected bowel is 12 cm.”

    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65. 
  • “Lymphoma of the small bowel commonly demonstrates an infiltrative pattern causing diffuse bowel wall thickening with or without aneurysmal dilation and less often an “annular napkin-ring lesion” mimicking adenocarcinoma. Other patterns of small-bowel lymphoma include solitary or multiple nodules or large polypoid masses.The differential diagnosis for these findings includes Crohn's disease, adenocarcinoma, carcinoid, GI stromal tumor, or metastatic disease (eg, melanoma).”

    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65. 
  • “The survival rate for primary GI lymphoma is highly variable depending on stage, primary site, and subtype, but is generally good, ranging from 44%-67%.Distinguishing between primary and secondary GI lymphoma is clinically important, however, because primary GI lymphoma carries a better 5-year survival rate than disseminated secondary GI lymphoma and a significantly better survival rate than other common GI malignancies such as adenocarcinoma. Tumors are often amenable to chemotherapy and radiation, and can occasionally undergo surgical debulking or resection due to perforation or other acute complication.”

    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65. 
  • “Primary tumors arising in the mesentery are relatively rare.On the other hand, the mesentery is a frequent avenue of spread for malignant neoplasms through the peritoneal cavity and between the peritoneal spaces and the retroperitoneum. Patients with mesenteric neoplasms usually present with nonspecific symptoms of abdominal pain, weight loss, a palpable abdominal mass, or diarrhea. CT plays a critical role in achieving an accurate diagnosis of these neoplasms to guide patient management.”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “Desmoid tumors are rare, locally aggressive, nonencapsulated masses resulting from a benign proliferation of fibrous tissue. Abdominal desmoids can occur sporadically and develop anywhere in the abdomen, including the musculature of the abdominal wall, the retroperitoneum, and the pelvis. However, desmoids forming in the mesentery are especially common in patients with familial adenomatous polyposis (Gardner syndrome), occurring in 9%–18% of cases .”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “Sclerosing mesenteritis is a rare inflammatory condition of unknown cause that affects the root of the mesentery. The mesenteric fat is involved with a variable amount of inflammation, fatty necrosis, and fibrosis. When the inflammation predominates (so-called mesenteric panniculitis), patients generally present with acute pain. On CT images, mesenteric panniculitis appears as a focal area of increased attenuation within the mesenteric fat surrounded by a pseudocapsule (Fig 5), an appearance that has been described as “the misty mesentery”. Areas of fibrosis within the inflamed fat appear as linear bands of soft-tissue attenuation .”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “At CT, the most common manifestation of mesenteric carcinoid tumors is that of an enhancing soft-tissue mass with linear bands radiating in the mesenteric fat . Radiologic-pathologic correlation has shown that these radiating strands of soft tissue do not generally represent tumor infiltration along neurovascular bundles but rather result from the intense fibrotic proliferation and desmoplastic reaction in the mesenteric fat and the adjacent mesenteric vessels caused by the release of serotonin and other hormones from the primary tumor .”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “Lymphoma is the most common malignant neoplasm affecting the mesentery . Approximately 30%–50% of patients with non-Hodgkin lymphoma harbor disease in the mesenteric lymph nodes. Markedly mesenteric adenopathy can also be present in chronic lymphocytic leukemia. Patterns of mesenteric lymphoma at CT include multiple, rounded, mildly enhancing, homogeneous masses that often encase the mesenteric vessels  and produce the “sandwich sign.”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “Patterns of mesenteric lymphoma at CT include multiple, rounded, mildly enhancing, homogeneous masses that often encase the mesenteric vessels and produce the “sandwich sign” ; a large, lobulated, “cakelike,” heterogeneous mass with low-attenuation areas of necrosis displacing small bowel loops ; or an ill-defined infiltration of the mesenteric fat, particularly after successful chemotherapy. Bulky retroperitoneal adenopathy commonly accompanies the mesenteric disease and should be a clue to the diagnosis .”
    Mesenteric Neoplasms: CT Appearances of Primary and Secondary Tumors and Differential Diagnosis
    Sheth S, Horton KM, Garland MR, Fishman EK
    RadioGraphics Mar 2003, Vol. 23, No. 2:457–473
  • “ Retroperitoneal liposarcomas are rare mesenchymal tumors of the retroperitoneum that typically present with advanced disease and often carry a poor prognosis. Because of their rarity and anatomic location, these malignant tumors can cause a diagnostic dilemma and present several therapeutic challenges. They are usually associated with a high rate of recurrence despite grossly complete resection, thus requiring long-term and often indefinite follow-up.”
    Retroperitoneal Liposarcoma: A Comprehensive Review.
    Vijay A, Ram L.
    Am J Clin Oncol. 2013 Oct 16. [Epub ahead of print]
  • “When CT features are suggestive of WD, no further diagnostic tests are needed for tumor characterization. Moreover, CT can accurately identify most DD, thereby rendering their under-treatment unlikely; however, a CT-guided biopsy is needed to differentiate between DD and WD RPLS that contain focal nodular/water density areas, thereby avoiding their over treatment.”
    Computed tomography scan-driven selection of treatment for retroperitoneal liposarcoma histologic subtypes.
    Lahat G et al.
    Cancer. 2009 Mar 1;115(5):1081-90.
  • “ Retroperitoneal liposarcoma frequently recurs asymptomatically within 2 years, usually within 6 months-2 years, of the initial surgical resection. The CT features of recurrent liposarcoma are similar to those of the initial manifestation; recurrent liposarcoma shows rapid growth, with a mean tumor volume doubling time of 98 days (range, 46-151 days; median, 104 days).”
    Recurrence of retroperitoneal liposarcoma: imaging findings and growth rates at follow-up CT.
    Kim EY et al.
    AJR 2008 Dec;191(6):1841-6
  • “A liposarcoma is a malignant tumor of mesenchymal origin that is one of the most common primary neoplasms in the retroperi- toneum. Liposarcomas rarely arise in the mesentery or peritoneum. The only effective treatment for a retroperitoneal liposarcoma is surgical resection . Unfortunately, surgery is curative in only a minority of patients, and liposarcoma shows a high rate of local recurrence even when surgical mar-
    gins are negative for tumor.”
    Recurrence of retroperitoneal liposarcoma: imaging findings and growth rates at follow-up CT.
    Kim EY et al.
    AJR 2008 Dec;191(6):1841-6
  • “In our study, well-differentiated recurrent liposarcomas tended to have a more fatty at- tenuation. All of the well-differentiated li- posarcomas (n = 2) and one lesion of a mixed subtype that was well-differentiated, myx- oid, and pleomorphic had mainly fatty com- ponents, whereas most of the myxoid or dedifferentiated liposarcomas (86%, 6/7) manifested as mainly soft-tissue masses. ”
    Recurrence of retroperitoneal liposarcoma: imaging findings and growth rates at follow-up CT.
    Kim EY et al.
    AJR 2008 Dec;191(6):1841-6
  • “The CT features of recurrent liposarcoma such as attenuation are similar to those of the initial tumor, with a variety of findings ranging from subtle fatty masses to small well-enhancing nodular lesions. When inter- preting follow-up CT scans of patients who have undergone liposarcoma surgery, one should note the location and CT attenuation of the initial tumor. Because recurrent retro- peritoneal liposarcomas usually grow rapid- ly, a shorter follow-up interval (i.e., 3 months) would be helpful for the early detection of recurrent retroperitoneal liposarcomas.”
    Recurrence of retroperitoneal liposarcoma: imaging findings and growth rates at follow-up CT.
    Kim EY et al.
    AJR 2008 Dec;191(6):1841-6
  • “Common presenting symptoms included abdominal pain (n = 8, 27.6%), GI bleeding (n = 5, 17.2%) and symptoms of GI tract obstruction (n = 4, 13.8%). CT scan was the most commonly performed investigation (96.6%). Over half of resections (54.5%, n = 18) included small bowel resection. Mortality at 2 and 5 years was 66.4% and 73.1%. Of the 3 patients who underwent a second resection of GI metastases, one is still alive after 26 months of follow up; 2 patients died after 32.8 and 18.6 months.”
    Malignant melanoma of the gastro-intestinal tract: A case series.
    Patel K et al.
    Int J Surg. 2014 Feb 25 [Epub ahead of print]
  • “Clinicians should have a low threshold for investigating GI symptoms in patients with a history of malignant melanoma even in the case of early-stage primary disease. Re-resection should be considered in patients presenting with further GI metastases.”
    Malignant melanoma of the gastro-intestinal tract: A case series.
    Patel K et al.
    Int J Surg. 2014 Feb 25 [Epub ahead of print]
  • “ CT and MRI enterography are comparable first-line modalities for patients with suspected small bowel disease, but magnetic resonance enterography is favored given the absence of ionizing radiation. Capsule endoscopy is a reasonable alternative investigation in exploration of chronic gastrointestinal blood loss, but is best kept as a second-line test in patients with other symptoms.”
    Imaging the small bowel.
    Murphy KP et al.
    Curr Opin Gastroenterol. 2014 Mar;30(2):134-40
  • “Fluoroscopic studies such as barium follow through and small bowel enteroclysis are being replaced by the cross-sectional alternatives. Contrast-enhanced ultrasound is showing results comparable with CT and MRI, but concern remains regarding reproducibility, especially outside centres that specialize in advanced sonographic techniques.”
    Imaging the small bowel.
    Murphy KP et al.
    Curr Opin Gastroenterol. 2014 Mar;30(2):134-40
  • “ Primary gastrointestinal (GI) lymphoma most often arises from stomach, small bowel, or colon. The 2 most common subtypes of primary GI lymphoma include low-grade mucosa-associated lymphoid tissue lymphoma, strongly associated with Helicobacter pylori infection, and high-grade diffuse, large B-cell lymphoma. Primary GI lymphoma demonstrates a myriad of imaging manifestations that can commonly mimic other pathologies. Timely and accurate diagnosis remains important because treatment and prognosis of primary GI lymphoma differ significantly from other GI malignancies and even lymphoma of other primary sites.”
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65. Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65.
  •  “ Primary gastrointestinal (GI) lymphoma most often arises from stomach, small bowel, or colon. The 2 most common subtypes of primary GI lymphoma include low-grade mucosa-associated lymphoid tissue lymphoma, strongly associated with Helicobacter pylori infection, and high-grade diffuse, large B-cell lymphoma.”
    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65.
  • “ Primary GI lymphoma demonstrates a myriad of imaging manifestations that can commonly mimic other pathologies. Timely and accurate diagnosis remains important because treatment and prognosis of primary GI lymphoma differ significantly from other GI malignancies and even lymphoma of other primary sites.”
    Imaging of primary gastrointestinal lymphoma.
    Chang ST, Menias CO
    Semin Ultrasound CT MR. 2013 Dec;34(6):558-65.
  • “A small bowel mass in a patient with a known malignancy is likely a metastasis; the most common malignancy involving the small bowel is metastatic. Small bowel metastases are categorized by means of spread: Intraperitoneal seeding, hematogenous spread, or local extension.”
    CT Evaluation of Small Bowel Neoplasms:Spectrum of Disease
    Buckley JA, Fishman EK
    RadioGraphics 1998; 18:379-392
  • Metastases to the Small Bowel: Sites of Origin
    - Melanoma
    - Lung cancer
    - Carcinoid tumor
    - Ovarian cancer
    - Colon cancer
  • Metastases to the Small Bowel: Patterns of Spread
    - Intraperitoneal seeding
    - Hematogenous metastases
    - Direct extension
  • Metastases to the Small Bowel: Patterns of Spread
    - Intraperitoneal seeding
    - Mucinous tumors of the ovary, appendix or colon
    - Hematogenous metastases
    - Lung cancer, breast cancer, malignant melanoma,renal cell carcinoma
    - Direct extension
    - Pancreatic, biliary or colon cancers
  • “ A subepithelial lesion with a lesion to aorta ratio less than 0.86 in the portal venous phase or not in the gastric antrum or duodenum is never a glomus tumor. On the contrary, a subepithelial lesion with hemangioma like enhancement during dynamic CT is essentially a glomus tumor.”
    Gastroduodenal Glomus Tumors: Differentiation From Other Subepithelial Lesions Based on Dynamic Contrast-Enhanced CT Findings
    Hur BY et al.
    AJR 2011; 197:1351-1359
  • Small Bowel Neoplasms
    - Relatively Rare
    - 1-2% of all GI cancers arise in the small bowel
    - ACS: estimated 7570 new cases and 1100 deaths due to small bowel cancer in US in 2011
    - The US has among the highest age-adjusted incidence of small bowel tumors, worldwide
    - Increase in incidence in the US over last 30 years
  • Small Bowel Neoplasms
    Risks
    - Diet.: Eating high-fat foods may raise the risk of small bowel cancer. Regularly consuming smoked or cured foods may also increase a person’s risk.
    - Crohn disease.
    - Celiac disease.
    - Familial adenomatous polyposis (FAP). 
  • Small Bowel Neoplasms
    Presentation
    - Pain, nausea, vomiting
    - Weight loss, obstruction
    - GI bleeding
    - Lack of reliable clinical findings
    - Usually significant delay in diagnosis
  • Carcinoid Tumor
    1. Originate from enterochromaffin cells of the neuroendocrine system
    2. Classically categorized based on their origin from embryonic divisions of the alimentary tract
    - Foregut (lungs, bronchi, stomach)
    - Midgut (small bowel, appendix and proximal colon)
    - Hindgut (distal colon and rectum)
    3. More recently categorized based on malignancy
    - Benign, low grade, high grade-using histological differentiation, size, angioinvasion, & infiltration as criteria
  • Carcinoid Tumor
    - Arise in the bowel wall as a submucosal mass
    - Made up of small round regular cells containing a round nucleus and clear cytoplasm. Histologic diagnosis also relies on immunohistochemical stains and electron microscopy.
    - The presence of elevated excretion of 5-hydroxyindoleacetic acid (5-HIAA) is suggestive of a functioning carcinoid tumor.
  • Gastrointestinal Stromal Tumors
    - Mesenchymal tumors which typically arise in association with with the muscularis propria of gastrointestinal tract wall 
    - Most frequent in the stomach (60%),  but also can occur in the small bowel (30%) or elsewhere, including the colon and rectum (5%), esophagus (<5%)
    - 5% of small bowel malignancies
  • Gastrointestinal Stromal Tumors
    - Most occur 50-60 years ( rare < 40)
    - Can be familial (present often in 30’s)
    Symptoms
    - GI bleeding, anemia, abdominal pain, dyspepsia, palpable abdominal mass.
    - Nishida et al, 271 patients with stromal tumors, 2/3 had symptoms that correlated with tumors size. Tumors > 3 cm were more likely to demonstrate necrosis than tumors < 3 cm.
    - Obstruction is rare. Burkhill et al, 1/ 61 SBO
  • Gastrointestinal Stromal Tumors
    - Arise pathologically from the wall of the GI tract and can be characterized as benign, borderline, low or high malignant potential based on the pathologic appearance.
    - The vast majority express a mutant form of c-kit (CD117) that can be detected on routine staining.
    - C-kit is a growth factor receptor with tyrosine kinase activity. It is thought that mutations in the c-kit gene are causative for the development of gastrointestinal tumors. It is found in both benign and malignant GIST.  
  • Gastrointestinal Stromal Tumors
    - Characterized as benign, borderline, low or high malignant potential based on the pathologic appearance.
    - The vast majority express a mutant form of c-kit (CD117) that can be detected on routine staining.
    - C-kit is a growth factor receptor with tyrosine kinase activity. It is thought that mutations in the c-kit gene are causative for the development of gastrointestinal 
  • GIST
    CT Findings
    - intramural mass when small
    - Can grow endoluminal or exophytic
    - often central ulceration and /or necrosis
    - do not usually produce significant adenopathy
    - 3D CT is especially useful in determine organ of origin
  • Gastrointestinal Stromal Tumors
    10-30% are malignant
    Malignant risk increases with
    - Extragastric location
    - Size > 5cm
    - Extension into adjacent organs
    - > 1 mitosis per 50 high powered field
  • Duodenal Carcinoids: Facts
    -    Most common in second portion duodenum
    -    May be multiple
    -    Enhancement is common
    -    More common in patients with neurofibromatosis type I where lesions were periampullary
    -    Usually intraluminal polyp or a mural mass
  • “The CT features of an enhancing duodenal mass during the early phases of contrast
    enhancement is suggestive of the possibility of a carcinoid.”
    Duodenal Carcinoids: Imaging Features with Clinical-Pathologic Comparison
    Levy AD et al.
    Radiology 2005; 237:967-972
  • “Duodenal carcinoids are distinctly different tumors compared with their counterparts in the
    jejunum and ileum. Unlike duodenal carcinoids, jejunal and ileal carcinoids arise from serotonin
    producing enterochromaffin cells and commonly manifest imaging evidence of local serotonin
    production and bowel kinking, mesenteric desmoplasia, elastic vascular sclerosis and intestinal
    ischemia.”
    Duodenal Carcinoids: Imaging Features with Clinical-Pathologic Comparison
    Levy AD et al.
    Radiology 2005; 237:967-972
  • “ Duodenal carcinoids are neuroendocrine tumors that encompass a wide clinico-pathologic
    spectrum of hormonally functioning and nonfunctioning tumors that differ from jejunal and ileal
    carcinoids.”
    Duodenal Carcinoids: Imaging Features with Clinical-Pathologic Comparison
    Levy AD et al.
    Radiology 2005; 237:967-972
  • “ Duodenal carcinoids are uncommon tumors with a wide clinical-pathologic spectrum. They
    occur most commonly in the proximal duodenum and manifest as an intraluminal polyp or a
    mural mass.”
    Duodenal Carcinoids: Imaging Features with Clinical-Pathologic Comparison
    Levy AD et al.
    Radiology 2005; 237:967-972
  • “ The gastrointestinal tract is the most common extranodal site of involvement in NHL, with
    disease seen at some site in up to 20% of patients.”
    Extranodal Lymphoma From Head to Toe;Part 2, The Trunk and Extremities
    Thomas AG et al
    AJR 2011;197:357-364
  • Small Bowel Lymphoma: Facts
    -    Primary small bowel lymphoma is usually of B-cell origin
    -    More common in distal ileum due to increased lymphoid tissue
    -    May present on CT as;
    -    Infiltrative disease
    -    Aneurysmal dilatation
    -    Nodular feeling defects
    -    Endo-exenteric form with fistulae
  • Primary GI Lymphoma
    -    Sites of involvement in decreasing order of frequency are stomach, small bowel, colon and
    esophagus
    -    Usually MALT tumors (mucosa associated lymphoid tissue lymphoma).
    -    T-cell lymphomas are particularly prone to bowel wall involvement of the ileum and
    jejunum. They are aggressive and have higher rates of bowel perforation.
  • “ A distinction is made between primary gastrointestinal tract lymphoma, in which there is little
    retroperitoneal lymphadenopathy or hepatomegaly, and involvement of the gastrointestinal tract
    in disseminated NHL from other body sites.”
    Extranodal Lymphoma From Head to Toe;Part 2, The Trunk and Extremities
    Thomas AG et al
    AJR 2011;197:357-364
  • “ Identification of a mass clearly visible suggests strongly the presence of small bowel adenocarcinoma in Crohn disease patients but adenocarcinoma may be completely indistinguishable from benign fibrotic or acute inflammatory stricture. Knowledge of these findings is critical to help suggest the diagnosis of this rare but severe complication of Crohn disease.”
    Small Bowel Adenocrcinoma in crohn Disease:CT-Enterography Features with Pathological Correlation
    Soyer P, Hristova L, Boudghene F, Hoeffel C, Dray X, Laurent V, Fishman EK, Boudiaf M
    Abdom Imaging 2011 June 14 (Epub ahead of print)
  • “ Imaging of small bowel NET,even with combinations of CT,MR and radionuclide studies, underestimates the extent of peritoneal, mesenteric, and hepatic metastatic disease. Accurate staging of small bowel NET might be best performed at the time of laparotomy.”
    Role of imaging in the preoperative staging of small bowel neuroendocrine tumors
    Chambers AJ et al.
    J Am Coll Surg, 2010 Nov;211(5):620-627
  • “CT enteroclysis has the potential to be an excellent diagnostic method for the examination of carcinoid small-bowel tumors. It provides adequate image quality with multiplanar reformations, allows sufficient distention of the entire small bowel, and provides detailed information about small-bowel masses (size, location, and enhancement) and extraenteric abnormalities (liver metastasis, lymph nodes, and peritoneal metastasis).”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  • “The overall sensitivity and specificity of CT enteroclysis in identifying patients with small-bowel carcinoid tumors were 100% and 96.2%, respectively. The negative predictive value of CT enteroclysis was 100% and the positive predictive value, 94.7%. Pathologic findings confirmed small-bowel carcinoid tumors in 18 patients.”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  • “ CT enteroclysis findings were positive in 19 patients and negative in 25 patients. The sizes of the carcinoid tumors identified were 5-30 mm in axial diameter. These tumors were depicted as focal nodular lesions located in the small-bowel wall or as intraluminal polypoid masses with marked enhancement.”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  •  “ CT enteroclysis findings were positive in 19 patients and negative in 25 patients. The sizes of the carcinoid tumors identified were 5-30 mm in axial diameter. These tumors were depicted as focal nodular lesions located in the small-bowel wall or as intraluminal polypoid masses with marked enhancement. Twenty-two patients underwent only clinical follow-up, with a mean clinical follow-up time of 20 months. The overall sensitivity and specificity of CT enteroclysis in identifying patients with small-bowel carcinoid tumors were 100% and 96.2%, respectively. The negative predictive value of CT enteroclysis was 100% and the positive predictive value, 94.7%. Pathologic findings confirmed small-bowel carcinoid tumors in 18 patients.”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  • “At our institution, 44 patients with symptoms of suspected gastrointestinal carcinoid tumors underwent CT enteroclysis. Positive CT enteroclysis findings were compared with pathology results after surgical procedures (n = 19). Negative examinations were compared with surgery results (n = 3) or clinical follow-up (n = 22).”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  •  “At our institution, 44 patients with symptoms of suspected gastrointestinal carcinoid tumors underwent CT enteroclysis. Clinical symptoms were as follows: carcinoid syndrome (n = 3), abdominal pain with diarrhea (n = 24), hypervascular liver metastases (n = 7), subileus condition (n = 1), hypervascular peritoneal lesion (n = 3), abnormal ileal stenosis on optical colonoscopy (n = 3), and follow-up extraintestinal carcinoid lesion (n = 3). Positive CT enteroclysis findings were compared with pathology results after surgical procedures (n = 19). Negative examinations were compared with surgery results (n = 3) or clinical follow-up (n = 22).”
    Value of CT Enteroclysis in Suspected Small-Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010;194:629-633
  • CTA of the Small Bowel: Scan Protocol
    Oral contrast
    -Water
    -Omnipaque-350
    -VoLumen
    Intravenous contrast
    -100-120 cc of Omnipaque -350
    -Injection rate of 3-5 cc/sec
  • Carcinoid Tumor: CT Findings
    -Primary mass in bowel or in the mesentery
    -Desmoplastic reaction in the mesentery
    -Calcification of mesenteric mass
    -Liver metastasis (hypervascular)
  • Carcinoid Tumor of the Small Bowel: Facts
    -Tumor metastases occur in less than 2% of primary tumors <1 cm but in 85% of cases in tumors over 2 cm
    -Ileal tumors are most likely to metastasize
    -Over 90% of cases arise in the ileum
  • Carcinoid Tumor of the Small Bowel: Facts
    -Tumors secrete serotonin which is metabolized  by the liver to 5-HIAA and excreted in the urine
    -Liver metastases seen in over 90% of patients with the carcinoid syndrome
    -Liver metastases are usually hypervascular
  • Carcinoid Syndrome:
    GI Manifestations
    - Chronic diarrhea
    - Intestinal colic
     - Malabsorption syndrome
    - Small bowel ischemia and/or infarction (Carcinoid tumors can lead to mesenteric ischemia and infarction due to the tumors desmoplastic reaction and subsequent  encasement of blood vessels (arterial and venous))
  • Carcinoid Tumor of the Small Bowel: Facts
    -Most common in ileum and least common in duodenum
    - Average incidence in US is around 1 in 100,000 cases
     -More common in men
     -More common in African-Americans and lower for Hispanics
    - Epidemiology of cancer of the small intestine
    Pan SI, Morrison H
    World J Gastrointest Oncol 2011 March 15; 3(3):33-42
  • Small Bowel Tumors: Frequency
    - Adenocarcinoma       30-40%
    -Carcinoid tumors      35-42%
    - Lymphoma               15-20%
    - Sarcomas                 15-20%
  • Metastatic disease
    -Melanoma
    - Renal cancer
  • Small Bowel Tumors: Malignant
    Primary tumors
    -Adenocarcinoma
    -Lymphoma
    -Carcinoid
    -GIST (gastrointestinal stromal tumors)
  • “Cancer of the small intestine is very uncommon. There are 4 main histological subtypes: adenocarcinomas, carcinoid tumors, lymphoma and sarcoma. The incidence of small intestine cancer has increased over the past several decades with a four-fold increase for carcinoid tumors, less dramatic rises for adenocarcinoma and lymphoma and stable sarcoma rates.”
    Epidemiology of cancer of the small intestine
    Pan SI, Morrison H
    World J Gastrointest Oncol 2011 March 15; 3(3):33-42
  • Hypervascular Metastases to the GI Tract: Facts
    - Primary sites are most commonly melanoma and breast cancer
    - Less common sites of origin include renal cell carcinoma, choriocarcinoma, neuroendocrine tumors, mesenchymal sarcoma
  • Glomus Tumors: Facts
    - GI glomus tumors are nearly always in the stomach
    - Represent under 2% of all benign gastric tumors
    - Usually under 3 cm in size
    - Very vascular especially on arterial phase imaging
  • GIST Tumors: Facts
    Site of origin
    - Stomach 60-70% of cases
    - Small bowel 30% of cases
    - Rectum, esophagus, colon and appendix are rare sites of tumor
  • Neuroendocrine Tumors in the GI Tract: Facts
    - Appendix most common location
    - Small bowel is second most common location
    - Carcinoid syndrome occurs in less tha 10% of patients with neuroendocrine tumor
    - Classic carcinoid syndrome (flushing and diarrhea) does not occur without liver metastases
    - Metastases relate to size of primary tumor
    - 30% of small bowel carcinoids are multicentric
  • "A subepithelial mass, which was previously called a submucosal mass, is defined as a mass covered with normal appearing mucosa, whether the underlying process is intramural or extramural in origin."

    Hypervascular Subepithelial Gastrointestinal Masses: CT-Pathologic Correlation
    Lee NK et al.
    RadioGraphics 2010; 30:1915-1934

  • Hypervascular Subepithelial GI Masses: Differential Dx
    - Neuroendocrine tumors
    - GI stromal tumors
    - Glomus tumor
    - Hemangioma
    - Angiosarcoma
    - Kaposi sarcoma
    - Hypervascular metastases
    - Heterotopic tissues
    - Vascular structures
  • "The overall sensitivity and specificity of CT enteroclysis in identifying patients with small bowel carcinoid tumors were 100% and 96.2%, respectively. The negative predictive value of CT enteroclysis was 100% and the positive predictive value,94.7%."

    Value of CT Enteroclysis in Suspected Small Bowel Carcinoid Tumors
    Kamaoui I et al.
    AJR 2010; 194:629-633

  • Small Bowel GIST Tumors: Differential Diagnosis

    - GIST
    - Lymphoma
    - Adenocarcinoma
    - Metastatic disease
  • Small Bowel: GIST Tumors: Facts

    Patients with neurofibromatosis I have an increased incidence of GIST’s and may have multiple GIST’s
  • Small Bowel: GIST Tumors: Location

    - Stomach 70%
    - Small intestine 20-30%
    - Rectum
    - Colon
    - Esophagus
  • "In conclusion, we found that CT features, other than tumor size, cannot helpfully predict GIST malignancy and that the malignant potential of small GIST tumors (<5cm) cannot be determined on CT."

    Gastrointestinal Stromal Tumors of the Stomach: CT Findings and Prediction of Malignancy
    Kim HC et al.
    AJR 2004;183:893-898
  • Small Bowel: GIST Tumors: Clinical Presentation

    - GI bleeding from mucosal ulceration
    - Hematemesis, melena, anemia
    - Abdominal pain or discomfort
    - Incidental finding on CT exam
  • Small Bowel: Malignant GIST vs Benign GIST Tumor

    - Malignant tumors were usually predominately extraluminal, heterogeneous and necrotic
    - Benign tumors were usually endoluminal, homgeneous and smooth or ovoid
  • "Although presence of an ulcer, mesenteric fat infiltration, direct organ invasion, and metastases were more frequently observed in tumors with a high mitotic rate, no CT feature, other than size, was found to have predictive value with respect to malignant GIST tumors of the stomach."


    Gastrointestinal Stromal Tumors of the Stomach: CT Findings and Prediction of Malignancy
    Kim HC et al.
    AJR 2004;183:893-898
  • MDST of the Small Bowel: Study Protocol and Design

    - MDCT 64 slice scanner
    - .6 mm collimation
    - .6-.75 mm slice thickness
    - .4-.5 mm interval reconstructions
  • "It is important for the radiologist to be familiar with the CT appearance of various small bowel tumors and the value of utilizing 3D imaging for diagnosis and for surgical planning."

    Multidetector-Row Computed Tomography and 3-Dimensional Computed Tomography Imaging of Small Bowel Neoplasms
    Horton KM, Fishman EK
    J Comput Assist Tomogr 2004;28:106-116
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