Imaging Pearls ❯ Chest ❯ Mediastinal Masses
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- “Castleman disease is a rare lymphoproliferative disease commonly occurring as a benign localized mass of lymph nodes in the mediastinum. Given that Castleman disease presents as asymptomatic or through non-specific thoracic symptoms, detection is considered complex. Ultimately, surgical resection is the preferred course of action with a greater than 90% relapse-free survival and no malignant transformation reported.”
CT of Castleman disease in the mediastinum.
Lugo-Fagundo E, Lugo-Fagundo C, Weisberg EM, Fishman EK.
Radiol Case Rep. 2023 Jan 11;18(3):1161-1163 - “Castleman disease (CD), also known as angiofollicular lymph node hyperplasia or lymph node hyperplasia, was originally described as a benign lymph-node hyperplasia resembling thymoma by Benjamin Castleman in 1954 . With the majority of cases located in the chest (70%) along the tracheobronchial tree in the mediastinum or lungs, other common sites of presentation include the neck, pelvis, retroperitoneum, and muscle . Given that patients are usually asymptomatic or present with non-specific symptoms, and there is no significant sex predominance or distinguishable risk factor in its development, CD is considered a challenging preoperative diagnosis and a definite verdict is not established until after tumor resection.”
CT of Castleman disease in the mediastinum.
Lugo-Fagundo E, Lugo-Fagundo C, Weisberg EM, Fishman EK.
Radiol Case Rep. 2023 Jan 11;18(3):1161-1163 - Castleman disease is a rare nonmalignant lymphoproliferative disorder. Clinically, CD is characterized as either multicentric CD (MCD), meaning that it involves multiple lymphatic regions, or unicentric CD (UCD), involving a single lymph node or one region of lymph nodes . While UCD is clinically more predominant, MCD, which has a less favorable prognosis, is divided into 3 subgroups: human herpes virus-8-associated MCD disease, idiopathic MCD, and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes-associated MCD. Furthermore, CD is distinguished by 2 pathological subtypes, the plasma cell and hyaline-vascular variants
CT of Castleman disease in the mediastinum.
Lugo-Fagundo E, Lugo-Fagundo C, Weisberg EM, Fishman EK.
Radiol Case Rep. 2023 Jan 11;18(3):1161-1163 - With an estimated annual incidence of 4,900 to 6,000 patients in the United States, unicentric CD accounts for approximately 70% of patients with CD and is typically found in adults between the ages of 30-40, with a faint prevalence among women [6,9]. The typical locations of emergence include the chest (29%), neck (23%), abdomen (21%), and retroperitoneum (17%), as well as the axilla, pelvis, and groin, with rare involvement seen in the lungs, trachea, esophagus, and the spleen. Additionally, most patients present with localized, asymptomatic adenopathy. Surgical resection is the treatment of choice, with radiotherapy considered as an alternative in instances where the mass is unresectable. In the case of inflammation, rituximab, steroids, and embolization are also deemed viable treatment options
CT of Castleman disease in the mediastinum.
Lugo-Fagundo E, Lugo-Fagundo C, Weisberg EM, Fishman EK.
Radiol Case Rep. 2023 Jan 11;18(3):1161-1163
- Lemierre syndrome is a rare and potentially life-threatening complication of bacterial infections that usually affects previously-healthy adolescents and young adults. It most commonly develops in association with a bacterial throat infection, but it may develop in association with an infection involving the ears, salivary glands (parotitis), sinuses, or teeth; or in association with an Epstein-Barr infection.[1] The bacteria typically responsible for infection in Lemierre syndrome is Fusobacterium necrophorum, although a variety of bacteria can be responsible. In people with Lemierre syndrome, the initial infection spreads into tissues and deep spaces within the neck, leading to the formation of an infected blot clot (septic thrombophlebitis), sometimes made up of pus, in the internal jugular vein (the blood vessel that carries blood away from the brain, face, and neck).
https://rarediseases.info.nih.gov/diseases/6882/lemierre-syndrome - “Advanced Lemierre syndrome is a life-threatening condition.The current mortality (death due to the syndrome) is estimated to be between 5% and 18%, depending on the source of the data. However, as the mortality in the pre-antibiotic era reportedly was 90%, the outlook for people with Lemierre syndrome has improved significantly due to advances in antibiotic therapy and high-level intensive care.Receiving the diagnosis as quickly as possible and starting appropriate treatment increases the chance of survival. Severe complications of Lemierre syndrome may include osteomyelitis (bone infection), meningitis, acute respiratory distress syndrome, and septic shock.”
https://rarediseases.info.nih.gov/diseases/6882/lemierre-syndrome - “The identification of thrombophlebitis of the IJ vein is the first hard evidence to suggest Lemierre’s syndrome in many patients. It is likely true that, as with our patient, these imaging studies are ordered in the majority of patients to assess for deep space infections of the neck and not IJ vein thrombophlebitis. Duplex ultrasonography, CT and magnetic resonance imaging have all been used for IJ vein imaging, with CT being most commonly requested in patients with Lemierre’s syndrome. Many authors consider contrast-enhanced CT as the preferred study in this setting as it allows for visualization of surrounding structures and is the most readily available.”
Lemierre's syndrome.
Eilbert W, Singla N.
Int J Emerg Med. 2013;6(1):40. - “Lemierre’s syndrome occurs primarily in young, otherwise healthy individuals and is characterized by a history of recent oropharyngeal infection, clinical or radiological evidence of IJ venous thrombosis and anaerobic bacteremia caused primarily by F. necrophorum. This is a rare illness in the modern era of antibiotic therapy, though it has been reported with increasing frequency in the twenty-first century. Lemierre’s syndrome should be suspected in young, healthy patients with prolonged symptoms of pharyngitis followed by symptoms of septicemia or pneumonia, or an atypical lateral neck pain. Diagnosis is often confirmed by the identification of IJ vein thrombophlebitis by an imaging study and growth of anaerobic bacteria on blood culture. Prolonged antibiotic therapy is the cornerstone of treatment, occasionally combined with anticoagulation.”
Lemierre's syndrome.
Eilbert W, Singla N.
Int J Emerg Med. 2013;6(1):40.
- Mediastinal Widening on a CXR
- Thoracic aortic aneurysm of the ascending and proximal descending aorta
- Aortic dissection of ascending and proximal descending aorta
- Unfolding of the aorta
- Traumatic aortic rupture
- Hilar lymphadenopathy either infectious or malignant
- Mediastinal masses like lymphoma, seminoma, thymoma
- Mediastinitis
- Cardiac tamponade
- Fractured ribs or thoracic vertebrae - “In the era of cross-sectional imaging, mediastinal abnormalities can easily be identified. However, these abnormalities often manifest initially at conventional radiography. Chest radiography is a very common examination, and radiographic identification of an unexpected mediastinal mass is important. Knowledge of the normal mediastinal reflections that can be appreciated at conventional radiography is crucial to identifying a mediastinal mass. These mediastinal reflections can also help identify the location of a mass, thereby aiding in differential diagnosis and possibly influencing the choice of modality for further assessment.”
A Diagnostic Approach to Mediastinal Abnormalities
Camilla R. Whitten et al.
RadioGraphics 2007; 27:657– 671 
- “The initial search starts at the most common location for parathyroid lesions—around the thyroid. The superior parathyroid gland has a more consistent location posterior to the mid-to-upper third of the thyroid gland. The inferior parathyroid gland lies inferior, lateral, or posterior to the lower third of the thyroid.The arterial phase should be the focus of the initial review because this is the phase in which the attenuation of the parathyroid adenoma will be highest, with reported mean attenuation ranging from 138 to 180 HU. The radiologist should search for a vividly enhancing lesion that is oval or round in shape in the typical locations around the thyroid gland.”
How to Perform Parathyroid 4D CT: Tips and Traps for Technique and Interpretation
Hoang JK et al.
Radiology 2014; 270:15–24 - • The role of four-dimensional (4D) CT is to enable accurate localization of the parathyroid adenoma in eutopic and ectopic locations and to depict multiglandular disease.
• The 4D CT protocol is composed of multiple phases (typically two to four phases) and reformatted images in three planes.
• Characteristic contrast enhancement pattern for a parathyroid adenoma is peak enhancement at the arterial phase, washout of contrast material from the arterial to delayed phase, and low attenuation on the non–contrast enhanced images.
• The morphologic imaging findings of parathyroid adenomas include central low attenuation change, lobulated margins, and a polar vessel sign.
How to Perform Parathyroid 4D CT: Tips and Traps for Technique and Interpretation
Hoang JK et al.
Radiology 2014; 270:15–24 - “The superior glands tend to be more consistent in location with most (> 90%) glands located deep in relation to the mid portion of the superior pole of the thyroid near the cricothyroid junction. Infrequently, the superior glands can be seen more inferiorly, deep in relation to the mid pole of the thyroid lobes (4%), or they may be located at or above the most superior aspect of the thyroid (3%). Rarely, the superior glands can be found in the retropharyngeal (1%) or retroesophageal (1%) spaces or in the thyroid gland itself (0.2%).The inferior parathyroid glands are more variable in location but most commonly are located inferior, posterior, or lateral to the lower thyroid pole (69%). Because of their common origin with the thymus gland, they can also commonly be found more inferiorly in the neck, in the thymic tongue, or in the cervical portion of the thymus (26%). Very rarely, the inferior parathyroid glands can fail to descend with the thymus and may remain cephalad to the superior glands. Inferior glands can also be found in the anterior mediastinum with the thymus (2%) or even inferior to the thymus gland in the mediastinum (0.2%).
Parathyroid Imaging: Technique and Role in the Preoperative Evaluation of Primary Hyperparathyroidism
Nathan A. Johnson, Mitchell E. Tublin, and Jennifer B. Ogilvie
American Journal of Roentgenology 2007 188:6, 1706-1715 - “Axial contrast-enhanced thin-collimation CT images through the neck show intense enhancement in the typical locations for parathyroid tissue in the setting of adenoma. Scanning from the skull base through the mediastinum has the additional advantage of detecting most ectopic glands. In cases of failed initial parathyroidectomy, artifacts from surgical clips placed in the neck often limit the diagnostic quality of CT. Reported sensitivities of CT range from 46% to 87% . Combined studies of sonography and CT suggest that supplemental CT will detect few additional adenomas over sonography alone. Thus, CT is usually reserved for cases of failed parathyroidectomy or in cases of altered anatomy, in which CT may aid in operative planning.Recent studies have combined 99mTc-sestamibi SPECT with coregistered CT in an attempt to improve sensitivity by combining anatomic and functional information, but results from these initial studies are conflicting in their conclusions about the added usefulness of CT. More study is required before the appropriate usefulness of this combined technique is established.”
Parathyroid Imaging: Technique and Role in the Preoperative Evaluation of Primary Hyperparathyroidism
Nathan A. Johnson, Mitchell E. Tublin, and Jennifer B. Ogilvie American
Journal of Roentgenology 2007 188:6, 1706-1715 - Fibrosing mediastinitis is a condition that affects the area between the lungs (mediastinum) which contains the heart, large blood vessels, windpipe (trachea), esophagus, and lymph nodes. People with fibrosing mediastinitis have varying amounts of scar tissue in the mediastinum which may cause problems for the organs located there.For example, some affected people may develop blocked airways that can interfere with lung function. Others may have compressed blood vessels which can slow or prevent blood flow to and from the heart. The exact cause of fibrosing mediastinitis is not fully understood, but it is not inherited. Many cases are linked to a specific type of fungal infectioncalled histoplasmosis.Treatment depends on which structures of the mediastinum are affected, the severity of the scarring and, in some cases, the cause of the condition
NIG GARD
https://rarediseases.info.nih.gov/diseases/8337/fibrosing-mediastinitis2014 - The signs and symptoms of fibrosing mediastinitis depend on which structures of the mediastinum are affected (i.e. the heart, large blood vessels, windpipe, esophagus, and lymph nodes) and the severity of the scarring. Some people with this condition have only a single mass of scar tissue while others develop more extensive scarring that affects the entire mediastinum and may even extend into the neck or lungs. Many symptoms of fibrosing mediastinitis arise when the esophagus, blood vessels and/or airways become blocked or compressed. Signs of these problems may include Cough, Shortness of breath, Recurrent lung infection, Hemoptysis, Pleuritic chest pain, Difficulty swallowing, and Cor pulmonale
GARD
https://rarediseases.info.nih.gov/diseases/8337/fibrosing-mediastinitis2014 - “Fibrosing mediastinitis (FM) is a rare but potentially life-threatening proliferation of dense infiltrative fibrous tissue in the mediastinum that causes compression or obstruction of hilar or mediastinal organs. Arterial, venous and aerodigestive tract involvement is at the origin of symptoms and influences prognosis. The non-specific clinical presentation includes cough, dyspnea, recurrent pneumonia, hemoptysis, or pleuritic pain. The main accepted hypothesis is that the origin of this proliferation is secondary to an abnormal immunologic reaction.”
CT features of fibrosing mediastinitis
Alexandre Garin et al.
Diagnostic and Interventional Imaging, 2021 (in press) - "FM (also known as sclerosing mediastinitis or mediastinal fibrosis), is usually divided into two sub entities that are granulomatous fibrosing mediastinitis (GFM) and non-granulomatous fibrosing mediastinitis (NGFM). GFM represents 80 to 90% of all FMs. GFM is usually considered as an abnormal immunologic response following an infectious disease, mainly histoplasmosis and tuberculosis. FM has also been described after fungal infection such as blastomycosis, mucormycosis, or cryptococcosis.”
CT features of fibrosing mediastinitis,
Alexandre Garin et al.
Diagnostic and Interventional Imaging, 2021 (in press) - “On imaging, the fibrous proliferation is typically associated with stippled or dense localized calcifications and mainly involves the right paratracheal region, the subcarinal region and the hila, as observed in our series. The less common non-granulomatous subtype of FM, NGFM, also called diffuse or idiopathic FM, accounts for 10% to 20% of FMs. The infiltration involves multiple mediastinal compartments and the pulmonary hila, typically without calcifications. It may be associated with extra-thoracic locations, especially retroperitoneal fibrosis, sclerosing cholangitis or autoimmune pancreatitis or observed as a complication of autoimmune diseases, previous radiation therapy or treatment with methysergide.”
CT features of fibrosing mediastinitis
Alexandre Garin et al.
Diagnostic and Interventional Imaging, 2021 (in press)
- “Ectopic parathyroid glands arising due to abnormal embryological migration are found in 1–3% of the population and these combined together account for 20–25% of the cases of parathyroid adenoma and clinically present as PHP. Majority of them are located in the anterior mediastinum near the thymus, but, rarely, some are present in the visceral compartment of the mediastinum or paraesophageal position or in the aortopulmonary window or close to the right pulmonary artery near the tracheal bifurcation which requires open thoracotomy or thoracoscopic removal.”
A challenging case of an ectopic parathyroid adenoma
Roopal Panchani et al.
Indian J Endocrinol Metab. 2012 Dec; 16(Suppl 2): S408S410. - "The approach to ectopic parathyroid adenoma is faced with multiple challenges. First, the varied locations of ectopic glands make radiological support pivotal for accurate diagnosis. However, even the best of imaging modalities sometimes fail to identify the lesion accurately or even if successful, they consume a lot of time and expense. Second, neglecting the possibility of these ectopic adenomas results in a failed initial cervical exploration of PHP on several occasions. Accurate preoperative localization is the key to successful surgical removal. Coupling anatomical imaging like thin-slice contrast CT with functional scan (sestamibi) is most essential.”
A challenging case of an ectopic parathyroid adenoma
Roopal Panchani et al.
Indian J Endocrinol Metab. 2012 Dec; 16(Suppl 2): S408S410. - "Solitary parathyroid adenoma is a common cause of primary hyperparathyroidism, and is usually, located in a juxtathyroid position in the neck. Primary hyperparathyroidism often presents in an unusual manner, with 0.3-8% of the cases occurring due to an ectopically located parathyroid gland adenoma. An inability to locate the adenoma may delay the diagnosis of these cases and lead to further complications of hyperparathyroidism.”
“Ectopic Parathyroid Adenoma Presenting as a Mediastinal Mass.”
Vaidya, Aneesha et al.
Journal of clinical and diagnostic research : JCDR vol. 11,5 (2017): ED40-ED42. - "The parathyroid glands are arranged in two pairs, upper and lower. The lower pair originates from the dorsal wing of the third pharyngeal pouch, along with the thymus which originates from the ventral wing. Hence, the common descending route of the inferior parathyroid with the thymus, can explain their aberrant situation in the mediastinum. Ectopic parathyroid glands have been found to occur in various anatomic locations anywhere from the angle of the mandible to the mediastinum. The most common sites are the mediastinum, along the path of the vagus nerve and recurrent laryngeal nerve and within the thyroid parenchyma.”
“Ectopic Parathyroid Adenoma Presenting as a Mediastinal Mass.”
Vaidya, Aneesha et al.
Journal of clinical and diagnostic research : JCDR vol. 11,5 (2017): ED40-ED42. - "Hypercalcaemia with raised parathormone levels, or isolated hypercalcaemia, are diagnostic of primary hyperparathyroidism . Moran CA et al., described cases where patients were being reviewed for primary parathyroid tumour in the mediastinum, showed metabolic disturbances such as hypercalcaemia and hypophosphatemia. Thus, these derangements help to serve as a clue to suspect a parathyroid mass. Preoperative localization of the adenoma is critical, for which a Tc-99m-Methoxy Isobutyl Isonitrile (MIBI) scan has shown sensitivity of 80%-90%. The modality helps to reduce the requirement of repeated neck explorations, as was reported in a study by Abbas S et al., and proved useful in detecting the ectopic nature of the lesion in our case.”
“Ectopic Parathyroid Adenoma Presenting as a Mediastinal Mass.”
Vaidya, Aneesha et al.
Journal of clinical and diagnostic research : JCDR vol. 11,5 (2017): ED40-ED42.
- “Rosai-Dorfman disease represents a wide-spectrum disease not limited to lymph nodes. Radiologically, RDD has diverse imaging findings. However, most lesions were hypermetabolic on 18F-fluorodeoxyglucose positron-emission tomography/computed tomography and isointense on T1-weighted imaging. Patients with RDD have a high rate of comorbid diseases including autoimmune disease, viral infections, and cancer.”
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461 - “Rosai-Dorfman disease (RDD) or sinus histocytosis with mas- sive lymphadenopathy is a rare, classically nonmalignant, and proliferative disorder of histiocytes that was first described in 1969 by Rosai and Dorfman. The usual presentation is a young patient in his first or second decade of life with cervical and submandibular lymphadenopathy. Rarely, RDD may be associatedwith systemic symptoms such as fever, malaise, and weight loss. A high erythrocyte sedimentation rate, neutrophilic leukocytosis, anemia, and polyclonal gammopathy frequently present in RDD patients. No etiology has been established for RDD, but in ectious, neoplastic, autoimmune, and immunodeficiency-related causes have been hypothesized.”
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461 - “Radiographically, RDD has nonspecific image findings, and presentation varies according to the affected organ. Nodal disease presents as a pathological lymph node enlargement, with the cervical chain being the most commonly affected. Axillary, inguinal, hilar, mediastinal, and retroperitoneal lymph nodes are less frequently affected and usually smaller than the cervical chain.”
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461 - “Anatomically, the head and neck including cervical lymph nodes are the most commonly affected locations by RDD. The predilection of RDD to affect the head and neck is well documented.Among 423 RDD patients, head and neck RDD represented 38% of extranodal disease. However, Goyal et al reported subcutaneous tissue as the most common affected anatomical location by RDD.”
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461 - "Rosai-Dorfman disease represents a wide-spectrum disease not limited to the lymph nodes, with extranodal disease being possibly more common than nodal disease. Radiologically, RDD had diverse imaging findings. However, most lesions are hypermetabolic on PET/CT and isointense on T1-WI. In addition, we found a high rate of comorbid diseases in RDD patients, in- cluding autoimmune disease, viral infections, and cancer. Rosai- Dorfman disease may have a difference in organ involvement among ethnic groups.”
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461 - Main Points
Rosai-Dorfman disease is more likely to affect extranodal tis- sues, especially the head and neck. More than half (62.5%) of our population had a pure extranodal disease. Absence of nodal disease does not exclude RDD from the differential. Most RDD lesions are hypermetabolic on PET/CT and isointense on T1-WI MRI.
Thirty-two percent of our patients had comorbid diseases. The most common comorbid diseases in patients with RDD were autoimmune diseases, viral infections, and cancers.
Rosai-Dorfman disease organ affection is slightly different be- tween ethnic groups. Central nervous system RDD is more common in white ethnicity.
Disease Characteristics, Radiologic Patterns, Comorbid Diseases, and Ethnic Differences in 32 Patients With Rosai-Dorfman Disease
Mohamed Elshikh et al.
J Comput Assist Tomogr 2020;44: 450–461
- "Pericardial cysts are rare with an incidence of about 1 in every 100,000 persons and one in 10 pericardial cysts may actually be a pericardial diverticulum. Pericardial cysts and diverticula share similar developmental origin and may appear as an incidental finding in chest roentgenogram in an asymptomatic patient. CT scan is considered as best modality for diagnosis and delineation of the surrounding anatomy. Cardiac MRI is recommended in the evaluation of the compressive effects caused by the pericardial cysts. The authors recommend echocardiography for serial follow up and image guided aspiration of the pericardial cyst in presence of compressive effects leading to cardiovascular and airway symptoms.”
Current concepts of diagnosis and management of pericardial cysts.
Kar SK1, Ganguly T2.
Indian Heart J. 2017 May - Jun;69(3):364-370 - "Cystic lesions within the pericardial space are a rare entity and comprise 7% of the mediastinal masses and 33% of mediastinal cysts. The incidence of a pericardial cyst is 1 in 100,000 populations and most of the pericardial cysts presenting as mediastinal opacity are detected incidentally.They are usually found in the third or the fourth decade of the life and male and female are affected equally.In 70% of the cases, these cysts are located in right cardiophrenic angle, in 22% cases in the left cardiophrenic angle and in 8% cases are located in the posterior or the anterior-superior part of the mediastinum.”
Current concepts of diagnosis and management of pericardial cysts.
Kar SK1, Ganguly T2.
Indian Heart J. 2017 May - Jun;69(3):364-370 - “Most of the cases (50–75%) are asymptomatic and are diagnosed incidentally during radiological investigations ordered as routine investigation for other causes of illness. Symptoms may appear due to compression of the nearby structures, such as heart, great vessels, oesophagus and the tracheobronchial tree.”
Current concepts of diagnosis and management of pericardial cysts.
Kar SK1, Ganguly T2.
Indian Heart J. 2017 May - Jun;69(3):364-370 - “Computerised tomography scan (CT scan) is considered as the best modality for the diagnosis as it provides an excellent delineation of the pericardial anatomy and can aid in the precise localization and characterization of various pericardial lesions, including effusion, pericardial thickening, pericardial masses, and congenital anomalies helping in surgical decision making. Inaccuracies in diagnosis arise when the cyst is in an unusual location, or the protein content of the cyst fluid is high.”
Current concepts of diagnosis and management of pericardial cysts.
Kar SK1, Ganguly T2.
Indian Heart J. 2017 May - Jun;69(3):364-370
- "The thymus changes with age. Its shape and the proportion of solid tissue and fat vary between individuals, yet there is no comprehensive work describing the size and morphology of the normal thymus on CT. As a result, many adults with some preserved soft tissue in the thymus may undergo extensive work-up to exclude mediastinal tumor. "
Normal CT characteristics of the thymus in adults
Author links open overlay panel
Simanovsky N et al.
European Journal of Radiology
Volume 81, Issue 11, November 2012, Pages 3581-3586 - "Thymic density and volume decreased progressively with age. No solid tissue component was seen in the thymus in patients older than 54 years. In the majority of patients, the thymus had an arrowhead shape, with middle position. However, great variability in thymic shape and border were noted. There was a highly significant relationship between density and patient age (p < 0.0001). "
Normal CT characteristics of the thymus in adults
Author links open overlay panel
Simanovsky N et al.
European Journal of Radiology
Volume 81, Issue 11, November 2012, Pages 3581-3586 - Our study demonstrated a spectrum of appearance of a normal thymus on CT and the sex difference in the middle and older age groups. In the present cohort from the FHS with the mean age of 58.9 years, only 8% (208/2540) of overall participants had thymic glands with half or more soft-tissue parenchyma (Scores 2 and 3), and 74% (1869/2540) showed a complete fatty replacement of the thymic gland due to advanced involution."
Normal Thymus in Adults: Appearance on CT and Associations with Age, Sex, BMI and Smoking
Tetsuro Araki et al.
Eur Radiol. 2016 January ; 26(1): 15–24 - "In the present study, meticulous measurements of the thymic glands revealed that those in male were significantly larger than those in female, thus justifying the data split according to sex, providing reference values for the size of a normal thymus. However, it should be noted that thymus glands at middle and older age, especially in male, are usually not applicable for measurements because of advanced fatty degeneration with an obscured contour. Moore et al suggested that the overall size of the thymus may not change with aging in adults."
Normal Thymus in Adults: Appearance on CT and Associations with Age, Sex, BMI and Smoking
Tetsuro Araki et al.
Eur Radiol. 2016 January ; 26(1): 15–24 - "We aimed to combine previously described pregnancy specific CTPA technique alterations with a dose reduction strategy and a low kVp technique to yield a low dose CTPA protocol specifically tailored to pregnant patients, without a reduction in clinical image quality. The results demonstrate that by using a low kVp CTPA technique tailored to pregnancy, effective doses under 1 mSv are routinely achievable in a pregnant population."
Low dose computed tomography pulmonary angiography protocol for imaging pregnant patients: Can dose reduction be achieved without reducing image quality?
Halpenny D et al.
Clinical Imaging: Volume 44, July–August 2017, Pages 101-105
- “A diameter ≤3 cm and an unenhanced CT value >20 Hu were independent factors of incorrect diagnosis of chest CT. VATS is a reliable approach for the surgical resection of thymic cysts. We think that local resection is adequate for simple thymic cysts. However, thymectomy is necessary when there is suspicion of a thymoma or multilocular thymic cyst, and radical thymectomy is advisable for patients with autoimmune diseases.”
Clinical features, diagnosis and thoracoscopic surgical treatment of thymic cysts. Wang X et al. J Thorac Dis. 2017 Dec;9(12):5203-5211 - “Thymic cysts are rare benign developmental anomalies and there is no consensus management for thymic cysts. The aim of this study was to disclose the efficacy of perioperative diagnosis for thymic cysts by chest computerized tomography (CT) and to elucidate the surgical procedure by video-assisted thoracic surgery (VATS) in the management of thymic cysts.”
Clinical features, diagnosis and thoracoscopic surgical treatment of thymic cysts. Wang X et al. J Thorac Dis. 2017 Dec;9(12):5203-5211 - “It is difficult to distinguish thymic cysts from the solid neoplasm of the thymus in some patients, and there are few large-scale studies that analyzed the preoperative diagnoses of thymic cysts. Preoperative diagnosis of a thymic cyst mainly depends on an imaging examination. In our study, only 37.0% patients presented with a widened mediastinum or mediastinal mass in the chest X-ray, and none were diagnosed with a thymic cyst. The chest X-ray can only be considered a screening examination. The chest CT is the most widely used imaging examination for mediastinal disease. For thymic cysts, the chest CT can describe the shape, contour, CT value, relationship to adjacent tissue, and the contrast-enhanced CT appearance. The typical imaging performance of the thymic cyst was oval in shape, and had a smooth contour, cystic density, homogeneous attenuation, and thin or imperceptible walls.”
Clinical features, diagnosis and thoracoscopic surgical treatment of thymic cysts. Wang X et al. J Thorac Dis. 2017 Dec;9(12):5203-5211 - “ A diameter ≤3 cm and an unenhanced CT value >20 Hu were independent factors of incorrect diagnosis of chest CT. VATS resection should be considered the primary therapeutic option for the management of thymic cysts. We think that local resection is adequate for simple thymic cysts. However, thymectomy is necessary when there is suspicion of a thymoma or multilocular thymic cyst. For patients with autoimmune diseases, a radical extended thymectomy is advisable.”
Clinical features, diagnosis and thoracoscopic surgical treatment of thymic cysts. Wang X et al. J Thorac Dis. 2017 Dec;9(12):5203-5211
- “Mediastinal masses span a wide histopathological and radiological spectrum. The most frequent lesions encountered in the mediastinum are thymoma, neurogenic tumours and benign cysts, altogether representing 60% of patients with mediastinal masses. Neurogenic tumours, germ cell neoplasms and foregut cysts represent 80% of childhood lesions, whereas primary thymic neoplasms, thyroid masses and lymphomas are the most common in adults.”
A diagnostic approach to the mediastinal masses
Juanpere S et al.
Insights Imaging. 2013 Feb; 4(1): 29–52. - “The mediastinum is demarcated by the pleural cavities laterally, the thoracic inlet superiorly and the diaphragm inferiorly. It is further divided into anterior, middle and posterior compartments by many anatomists . Anterior mediastinal tumours account for 50% of all mediastinal masses, including thymoma, teratoma, thyroid disease and lymphoma. Masses of the middle mediastinum are typically congenital cysts while those arising in the posterior mediastinum are often neurogenic tumours.”
A diagnostic approach to the mediastinal masses
Juanpere S et al.
Insights Imaging. 2013 Feb; 4(1): 29–52. - “Usual symptoms at presentation are cough, chest pain, fever/chills and dyspnea. Localizing symptoms are secondary to tumour invasion (respiratory compromise; paralysis of the limbs, diaphragm and vocal cords; Horner syndrome; superior vena cava syndrome), while systemic symptoms are typically due to the release of excess hormones, antibodies or cytokines.”
A diagnostic approach to the mediastinal masses
Juanpere S et al.
Insights Imaging. 2013 Feb; 4(1): 29–52. - “Hodgkin disease (HD) has a bimodal distribution of incidence peaking in young adulthood and again after the age of 50 years. Most patients experience constitutional symptoms. Four subtypes of HD are described: nodular sclerosis (by far the most common histological subtype), lymphocyte-rich, mixed cellularity and lymphocyte depleted HD. CR is abnormal in up to 76% of patients with HD, often showing enlargement of the prevascular and paratracheal nodes. Characteristic features on imaging are a homogeneous soft-tissue anterior mediastinal mass with mild to moderate contrast enhancement, irregular contours, surface lobulation, absence of vascular involvement, and high prevalence of associated mediastinal lymphadenopathy. Cystic and necrotic changes can be identified.”
A diagnostic approach to the mediastinal masses
Juanpere S et al.
Insights Imaging. 2013 Feb; 4(1): 29–52. - “The two most common forms of mediastinal non-Hodgkin disease (NHD) include diffuse large B-cell lymphoma and T-cell lymphoblastic lymphoma. T-cell lymphoblastic lymphoma mainly occurs in children and adolescents. The most common CT appearance is a large mediastinal mass representing thymic and lymph node enlargement, which compresses the airway and cardiovascular structures. Low attenuation areas reflecting necrosis are commonly seen. Primary mediastinal diffuse large B-cell lymphomas tend to occur in young to middle-aged adults with a mean age of 30. It accounts for 7% of all cases of NHD and about 10% of all cases of high-grade NHD .”
A diagnostic approach to the mediastinal masses
Juanpere S et al.
Insights Imaging. 2013 Feb; 4(1): 29–52.
- Thymoma: Facts
- Thymomas are defined as tumors originating in the epithelial components of the thymus
- 70% to 80% are totally encapsulated and classified as benign, and the remainder represents the group of malignant thymomas
- Maximal diameters of the invasive thymomas ranged from 3 to 10 cm, and thymic carcinomas ranged from 5 to 25 cm. - “Preoperative CT findings can predict the likelihood of successful surgical resection and could help to identify patients who might benefit from neoadjuvant chemotherapy.”
Preoperative computed tomography findings predict surgical resectability of thymoma.
Hayes SA et al
J Thorac Oncol. 2014 Jul;9(7):1023-30 - “Thymic neoplasms are rare tumors that account for less than 1% of all adult malignancies, with reported incidences of one to five cases per 1 million people per year . The primary epithelial neoplasms of the thymus are thymoma and thymic carcinoma, with thymoma being more common. Thymic carcinoma is a more aggressive disease that is often diagnosed with needle biopsy before treatment planning; it has been discussed elsewhere.”
Role of Imaging in the Diagnosis, Staging, and Treatment of Thymoma
Benveniste MFK et al.
RadioGraphics
Volume 31, Issue 7 pp. 1847-1861 - “Thymomas typically occur in patients older than 40 years of age, are rare in children, and affect men and women equally. Most thymomas are solid neoplasms that are encapsulated and localized to the thymus. Approximately one-third exhibit necrosis, hemorrhage, or cystic components, and approximately one-third invade the tumor capsule and the surrounding structures..”
Role of Imaging in the Diagnosis, Staging, and Treatment of Thymoma
Benveniste MFK et al.
RadioGraphics
Volume 31, Issue 7 pp. 1847-1861 - “The preoperative CT characteristics that correlated with an incomplete surgical resection included a lobulated tumor contour (p = 0.016), greater than or equal 50% abutment of the circumference of an adjacent vessel (p < 0.001), thoracic lymphadenopathy (p = 0.029), adjacent lung changes (p = 0.005) and pleural nodularity (p = 0.001). Tumor size was larger in the incompletely versus completely resected groups, with mean values of 9.7 and 6.9 cm (p value 0.013). On multivariate analysis, only degree of abutment of adjacent vessels and pleural nodularity were independent predictors of incomplete resection.”
Preoperative computed tomography findings predict surgical resectability of thymoma.
Hayes SA et al
J Thorac Oncol. 2014 Jul;9(7):1023-30 - “On multivariate analysis, only degree of abutment of adjacent vessels and pleural nodularity were independent predictors of incomplete resection.”
Preoperative computed tomography findings predict surgical resectability of thymoma.
Hayes SA et al
J Thorac Oncol. 2014 Jul;9(7):1023-30
- “ Pulmonary lymphoma is rare and represent less than 1% of primary lung cancer. Lung involvement is usually secondary. Primary pulmonary lymphoma encompass 10% of extranodal lymphoma. The majority are non-Hodgkin lymphoma (non-HL) and primary pulmonary HL is very uncommon. The diagnosis is only justified if hilar lymph nodes are uninvolved and disease elsewhere has been excluded.”
Primary pulmonary classic Hodgkin’s lymphoma
Binesh F et al.
BMJ Case Rep. 2011 Jun 29;2011 - “The pulmonary lesions are single nodule in one third of the patients and multiple nodules in one half. Occasionally, bilateral reticulonodular infiltrates or pulmonary consolidation are seen. Upper lobes involvement are more common, and there may be cavitations in the larger ones.”
Primary pulmonary classic Hodgkin’s lymphoma
Binesh F et al.
BMJ Case Rep. 2011 Jun 29;2011
- “Thymoma is the most common primary neoplasm of the anterior mediastinum, but it accounts for <1% of all adult malignancies. It is the most common of the thymic epithelial neoplasms, which, in addition to thymoma, include thymic carcinoma and thymic carcinoid.”
Advances in Thymoma imaging
Marom EM
J Thorac Imaging 2013 28(2):69-80 - “Currently, imaging is predominantly carried out with computed tomography (CT). In selected cases, there is a role for magnetic resonance imaging and F-fluorodeoxyglucose positron emission tomography in the investigation of an anterior mediastinal mass suspected to be thymoma. Because patients with advanced thymoma receive neoadjuvant chemotherapy, radiologists should be familiar with the staging system of thymoma and the imaging features of advanced-stage thymoma to identify such patients before surgery.”
Advances in Thymoma imaging
Marom EM
J Thorac Imaging 2013 28(2):69-80
- Mediastinal Adenopathy: Differential Diagnosis
- Lung cancer
- Lymphoma
- Metastatic disease (Renal Cancer is most common)
- Sarcoidosis
- TB
- Castleman’s Disease
- Histoplasmosis - “Mediastinal lymph node enlargements are caused most often by lymphoma, metastatic carcinoma, sarcoidosis, and infection, either directly by organisms, such as Mycobacterium tuberculosis, Histoplasma capsulatum, and others, or as a hyperplastic reaction to the presence of organisms within the lungs.”
Evaluation of mediastinal lymph nodes using 18F-FDG PET-CT scan and its histopathologic correlation
Kumar A et al.
Ann Thorac Med. 2011 Jan-Mar; 6(1): 11–16. - “Pulmonary metastases usually appear as well-defined round or ovoid nodules on both chest radiography and CT. They can be solitary or multiple and typically range in size from 0.5 to 2 cm in diameter. They are one of the well-known causes of “cannonball” metastases. Pulmonary metastases are usually asymptomatic. Mediastinal lymph node involvement is also a frequent finding and tends to involve the hilar, subcarinal, and paratracheal regions. Both large parenchymal lung and mediastinal lesions may show central necrosis.”
Imaging in Metastatic Renal Cell Carcinoma
Griffin N et al
American Journal of Roentgenology. 2007;189: 360-370.
- Lymphoma: Facts
- Hodgkins is most common in the anterior mediastinum
- Nodes rarely calcify unless the patient has undergone radiation therapy or occasionally chemotherapy
- Parenchymal involvement at time of presentation is rare (under 10%)
- Non-Hodgkin’s disease more commonly involves the lung parenchyma - Anterior Mediastinal Mass: Differential Diagnosis
- Lymphoma
- Germ cell tumor
- Thymoma
- Thyroid goiter
- Inflammatory nodes like TB or Sarcoidosis
"CT and MR imaging of the thorax are helpful to characterize lesions initially identified at plain radiography. This characterization helps narrow the differential diagnosis when a lesion is detected in this location."
Lesions of the Cardiophrenic Space: Findings at Cross Sectional Imaging
Pineda V et al.
RadioGraphics 2007; 27:19-32- Pericardial Cyst: Facts
- More common in right cardiophrenic space (77%)
- Congenital in origin
- Always asymptomatic
- Attenuation usually 0-20 HU
- No enhancement on contrast enhanced studies - Lesions of the Cardiophrenic Space: Differential Diagnosis
- Prominent cardiac fat pad
- Diaphragmatic hernia (Morgagni hernia)
- Pericardial fat necrosis
- Pericardial cysts
- Thymic tumors
- Lymphoma
- Adenopathy - Paraganglioma: Facts
Paragangliomas are found predominantly in the abdomen (85%) and the thorax (12%), and only 3% are found in the head and neck region. Most occur as single tumors. When they occur in multiple sites they are usually found as a part of a heritable syndrome such as multiple endocrine neoplasia types II-A and II-B and SDH-related mutations. - Paraganglioma: Facts
- Rare neuroendocrine tumors of chromaffin cell origin
- When they arise outside the adrenal glands in extraadrenal neuroendocrine tissue they are called paragangliomas
- May arise in the chest from the aortic body - Paraganglioma: Facts
- Patients may have mutations in the mitochondrial II genes SDHB, SDHC and SDHD
- 15% of these tumors are extra-adrenal, 85% adrenal in origin (pheochromocytoma) - Paragangliomas: CT Findings
- Vasular lesions especially well enhanced on arterial phase imaging
- Multiple lesions at multiple sites may be seen in select cases and may be part of a familial disorder as well
- Carney syndrome- paraganglioma, pulmonary chondroma, and GI stromal tumor - Paragangliomas
"Paragangliomas of the aortic body and the great vessels have a characteristic imaging appearance. They originate from known sites of the branchiomeric paraganglia such as the aortic body."
Cross-Sectional Imaging of Paragangliomas of the Aortic Body and Other Thoracic Branchiomeric Paraganglia Balcombe J et al.
AJR 2007; 188:1054-1058 - Paragangliomas
"Aortic body paragangliomas are accompanied by other synchronous paragangliomas in 10% of cases."
Cross-Sectional Imaging of Paragangliomas of the Aortic Body and Other Thoracic Branchiomeric Paraganglia Balcombe J et al.
AJR 2007; 188:1054-1058 - Paragangliomas and Syndromes
- Carney’s triad Paraganglioma, pulmonary chondroma, and GIST tumor
- Hereditary Paraganglioma (J Med Genet 2002; 39:617-622) - Branchiomeric Paraganglia: Some Sites
- Carotid body
- Coronary paraganglia
- Pulmonary paraganglia
- Jugulotympanic paraganglia
- Subclavian paraganglia
- Laryngeal paraganglia - Extraadrenal Paragangliomas: CT Findings
- Homogeneous or heterogeneous hyperenhancing mass
- Range in size from 1 cm to over 20 cm
- Common locations are carotid body, jugular foramen, aorticopulmonary region, posterior mediastinum, abdominal paraaortic region including Organ of Zuckerkandl, and pelvis - Paraganglioma: Facts
- Neuroendocrine tumor which arises from the paraganglionic cells
- Pheochromocytoma is a paraganglioma of the adrenal gland
- Usually 4th and 5th decades of life
- 10% are clinically silent and picked up incidentally - Paraganglioma: Facts
- Familial Paragangliomas are 10% of cases
- 35-50% of familial cases are multicentric
- Occur with MEN IIA and IIB, tuberous sclerosis, neurofibromatosis, and von Hippel Lindau disease. Also part of Carney’s triad with gastric leiomyosarcoma, chondroma and extraadrenal paraganglioma - Paraganglioma: Facts
"Although paragangliomas can occur in a variety of anatomic locations, the majority are seen in relatively predictable regions of the body."
Extraadrenal Paragangliomas of the Body: imaging Features
Lee KY et al.
AJR 2006; 187:492-504 - "Paragangliomas of the aortic body and the great vessels have a characteristic imaging appearance. They originate from known sites of the branchiomeric paraganglia such as in the aortic body."
Cross-Sectional Imaging of Paragangliomas of the Aortic Body and Other Thoracic Branchiomeric Paraganglia
Balcombe J et al.
AJR 2007; 188:1054-1058 - "Aortic body paragangliomas are accompanied by other synchronous paragangliomas in about 10% of cases."
Cross-Sectional Imaging of Paragangliomas of the Aortic Body and Other Thoracic Branchiomeric Paraganglia
Balcombe J et al.
AJR 2007; 188:1054-1058