Invasive thymomas typically spread locally (Fig. For masses localized within the anterior compartment of the mediastinum, computed tomography (CT) is a good diagnostic choice. Although CT and MRI findings are often of limited value in differentiating histologic subtypes of thymic epithelial neoplasms, certain findings have predictive value. Figure 16-4 Invasive thymoma. Differentiating abnormal mediastinal contours from the normal mediastinum on a chest radiograph and recommending appropriate further imaging evaluation are essential steps in correct diagnosis of mediastinal … Notice the thin strands of soft tissue attenuation, Malignant Forms (Seminoma, Choriocarcinoma, Embryonal Cell Carcinoma, Yolk Sac Tumor), The most important of these features is demonstration of continuity of the mass with the cervical thyroid gland. Imaging plays a critical role in the identification and evaluation of mediastinal … Age: usually 40 to 60 years old; unusual in patients younger than 30 years old, Associations: myasthenia gravis, hypogammaglobulinemia, red cell aplasia, and stiff-person syndrome, Well-defined, round, soft tissue density mass with homogenous enhancement, Usually located anterior to the junction of the heart and great vessels, Irregularly marginated mass with necrotic components and heterogeneous enhancement, Additional findings of invasion of adjacent mediastinal vascular structures, chest wall invasion, or contiguous spread along pleural surfaces (usually unilaterally). There are a variety of benign and malignant GCNs (Box 16-5). The thymus reaches its maximum weight at puberty and subsequently undergoes fatty involution over a 5- to 15-year period. Coronal (B) and sagittal (C) reformation images improve the assessment of the craniocaudal extent of the neoplastic mass (M) compared with axial images. Because of the geometry of the mediastinum most of these masses will be located in the anterior mediastinum. Although they are most commonly located anterior to the junction of the heart and great vessels, thymomas may occur at any level from the thoracic inlet to the diaphragm. The WHO classification scheme correlates with the likelihood of invasiveness, a factor that has an important influence on treatment and prognosis. Superior mediastinal mass - Lymphoma. Figure 16-7 Lymphoma. 16-3). Right parasagittal, T1-weighted MRI shows a homogeneous mass (arrows) that extends inferiorly from the right lobe of the thyroid gland to involve the middle and posterior mediastinal compartments. Neoplastic, inflammatory, or infectious lymphadenopathy (Box 16-7) is the most common cause of a middle mediastinal mass (Box 16-8). Algorithm for Imaging Evaluation of Mediastinal Masses, The most common thymic abnormality that manifests as an anterior mediastinal mass is, Thymoma. On chemical shift imaging, thymic hyperplasia is associated with a characteristic decrease in signal intensity within the thymus gland. In contrast, most other thymic abnormalities appear as a discrete mass rather than as uniform glandular enlargement. When located in the anterior mediastinum, thyroid masses are almost always located posterior to the great vessels, usually in a paratracheal location. When there is a mediastinal mass and you still can see the hilar vessels through this mass, then you know the mass does not arise from the hilum. Because GCNs grow rapidly and have a propensity to invade mediastinal structures, patients with malignant GCNs are more likely to be symptomatic. Thymolipomas most often occur in younger patients and are usually identified on chest radiographs as incidental findings. The diagnosis is often suspected on the basis of endocrine abnormalities in a patient with an anterior mediastinal mass. MRI also plays an important second-line role to CT by providing further tissue characterization in cases in which a mass is incompletely characterized by CT. For masses localized within the posterior mediastinum, MRI is usually preferred because of its superior ability to assess the relationship of the mass to the adjacent spine. A combination of fluid, fat, and calcification is frequently observed. Surgical excision of teratomas and dermoid cysts is usually curative. 16-6). Although the true prevalence of mediastinal masses is not known, a 0.9% prevalence of anterior or prevascular mediastinal masses was found among the 2,571 chest CTs of the 51% female cohort of the Framingham Heart Study, with a mean age of 59 years [1]. As with other midline anterior mediastinal masses, conventional radiographic findings are often limited to the lateral chest radiograph, which may demonstrate a well-defined mass in the normally clear retrosternal space. Lymphadenopathy often manifests as multiple, discrete masses (Fig. Thymic hyperplasia is usually identified on CT as enlargement of the thymus gland, which maintains its normal bilobed, arrowhead configuration (Fig. In about 20% of cases, there is evidence of calcification, which is typically curvilinear. It is helpful to identify the location of the mass since this significantly reduces the breadth of the … The first part is to determine that a mass is actually mediastinal, and the second part is to place it in the anterior, middle, or posterior mediastinum. The presence of an anterior mediastinal mass and unilateral pleural masses strongly suggests invasive thymoma. Thus, MR imaging is a completely noninvasive technique for the evaluation of mediastinal masses. Well-defined mass that extends from above the thoracic inlet, Displacement or compression of the trachea, Foci of calcification occasionally visible, Continuity with the cervical thyroid gland, Foci of high attenuation on noncontrast-enhanced images, Intense enhancement after intravenous contrast administration, Cystic areas and foci of calcification common. Axial, contrast-enhanced CT (A) at the level of main pulmonary artery shows a large, heterogeneously enhancing, anterior mediastinal mass with foci of low attenuation (arrows), consistent with necrosis. The most important of these features is demonstration of continuity of the mass with the cervical thyroid gland. Invasive thymomas typically spread locally (Fig. Anterior mediastinal masses generally arise from these structures. 16-1 and. In some cases, imaging features enable the radiologist to make a specific diagnosis. Axial CT shows an oval, homogeneous soft tissue mass, Thymic carcinoma. FDG-PET and FDG-PET/CT play important roles in staging lymphoma and in assessing the response to therapy. The radiologic workup depends on the location of the mass (Fig. Pleural dissemination, also referred to as, Thymic Hyperplasia: Associated Systemic Abnormalities. The superior extent of the mass (upper white arrow) extends above the thoracic inlet and is associated with rightward deviation of the trachea (black arrows). Identification of fat within the mass on CT or MRI suggests the diagnosis (Fig. Whereas anterior mediastinal masses from lymphoma typically demonstrate well-defined margins, invasion of adjacent lung parenchyma may result in irregular margins. Posterior mediastinal mass. Superior mediastinal mass - Lymphoma. They are often quite large at the time of presentation, and they may mimic cardiac enlargement on chest radiographs. Although the presence of calcification strongly suggests a diagnosis other than lymphoma, calcification frequently occurs in cases of treated lymphoma, but only rarely in untreated cases. In this situation, a barium swallow should be obtained. Thymic hyperplasia caused by hyperthyroidism. Mediastinum Lymph Node Map. Thymic lymphoid hyperplasia is most commonly associated with myasthenia gravis. Germ cell: A rare mediastinal mass is a germ cell a tumor. C, Axial noncontrast CT scan shows destruction of the sternum (black arrow) by the anterior mediastinal mass (white arrows). Parenchymal lung masses are generally almost completely surrounded by lung, forming an acute angle with the mediastinum. Thymic involvement may occur in up to one third of patients with Hodgkin’s lymphoma. Correlative nuclear medicine gallium imaging may be helpful because most Hodgkin’s lymphomas take up gallium avidly. Identification of these lymph node characteristics can shorten the lengthy differential diagnosis of mediastinal lymphadenopathy (Box 16-9). PET is especially helpful in this setting because it can differentiate a residual, benign, fibrotic tissue mass from incompletely treated, viable tumor. Figure 16-5 Thymic hyperplasia caused by hyperthyroidism. 1- Lymph nodes enlargement. They include irregular tumor margins; invasion of surrounding mediastinal fat, vascular structures, or chest wall; and irregular interface with the adjacent lung. Hodgkin disease has a bimodal age distribution, particularly affecting patients in their teens or 20s and those over age 50. This review is based on a presentation by Marilyn Siegel and was adapted for the Radiology … It is therefore no surprise that there are no distinguishing demographic features. Hover on/off image to show/hide findings. Clinically, an anterior mediastinal mass … The CT attenuation values are typically consistent with fluid; however, the appearance may vary if hemorrhage or infection complicates the cyst. However, most other anterior mediastinal masses are located anterior to the great vessels, and a mediastinal mass located anterior to the great vessels in a retrosternal location is unlikely to be of thyroid origin. After completing this journal-based SA-CME activity, participants will be able to: 1. An anterosuperior mediastinal mass can be caused by neoplastic and non-neoplastic pathology. Notice that one of the pleural masses is located within the minor fissure (open arrow). CT may show a mass with homogeneous soft tissue density, or it may appear heterogeneous, in which the low-attenuation areas represent necrosis. The mediastinum is the most common location of an intrathoracic mass in children. C, Axial CT image of the chest (filmed using lung windows) shows multiple pleural masses (curved arrows), including a pleural mass within the minor fissure (open arrow). A testicular exam and scrotal ultrasound is recommended when a mediastinal mass … When interpreting CT scans or MRI studies of patients with suspected or proven thymic neoplasms, signs of capsular invasion or extracapsular extension should be carefully sought. Radiology of Mediastinal Masses Evaluation of the mediastinum is an important part of the interpretation of a chest x-ray (CXR). Axial, non–contrast-enhanced CT image shows discrete, round, soft tissue masses, Mediastinal Lymphadenopathy: Characteristic Features, Thoracic Radiology: Imaging Methods, Radiographic Signs, and Diagnosis of Chest Disease, Radiography for the Critical Care Patient, Mediastinal mass detected on chest radiograph, Other studies:Gallium scan if Hodgkin’s lymphoma is suspectedRadioiodine scanif thyroid goiter issuspected, Other studies:MRI if there is acontraindicationto contrast and avascular abnormalityis suspected or ifvascular invasionis suspected. Right parasagittal, T1-weighted MRI shows a homogeneous mass, Neoplastic, inflammatory, or infectious lymphadenopathy (Box 16-7) is the most common cause of a middle mediastinal mass (, Mediastinal Lymphadenopathy Differential Diagnosis, Metastatic disease (bronchogenic carcinoma or extrathoracic primary, Viral infection (measles, infectious mononucleosis). 16-7). Axial CT shows an oval, homogeneous soft tissue mass (short solid arrows) in the anterior mediastinum, with a thin rim of peripheral calcification posteriorly (open arrow). It is usually accompanied by involvement of mediastinal lymph nodes. Figure 16-2 Thymoma. Only 10% of lymphomas which involve the mediastinum are primary (i.e. The “4 Ts” delineate the important entities in anterior mediastinal mass differential diagnosis—thymoma, thyroid, teratoma, and terrible lymphoma. Middle mediastinal lymphadenopathy is most reliably identified by the detection of a mass in an area that is known to have a specific lymph node—for example, a subcarinal, right paratracheal, azygos, or ductal node ( Fig 10.4 ).Because many of the processes to be considered involve multiple nodes in the same area, there is a strong but not invariable tendency for mediastinal … A, The posteroanterior chest radiograph shows a large, anterior mediastinal mass. On the one hand, a soft anterior mediastinal mass such as a thymolipoma may droop down along the heart border (, The ability of radiologists to localize mediastinal masses via CXR has atrophied because of CT. Certain signs (silhouette sign, hilum overlay and convergence signs, and cervicothoracic and thoracoabdominal signs) (, Generating a differential diagnosis for a mediastinal mass starts with a classification scheme. C, Axial, contrast-enhanced CT image at the level of the aortic arch shows the large, substernal component of the mass (arrows), which displaces the ascending aorta (A) and superior vena cava (S) posteriorly. Figure 16-8 Teratoma. Age: young patients, usually in third decade, Gender: malignant germ cell neoplasms have marked male predominance, Heterogeneous, predominately cystic mass with solid components, Presence of fat is suggestive; identification of a tooth, although rare, is diagnostic. A, The lateral chest radiograph reveals increased opacity in the normally clear retrosternal space (lower arrow) and a presternal soft tissue mass (upper arrow). The location and composition of these lesions are critical to narrowing the differential diagnosis. In some cases, CT and MRI provide complementary information, and both may be indicated. The mass contains foci of thyroid tissue that demonstrate intense enhancement and foci of low attenuation consistent with cysts. the anterior mediastinum include the thymus, lymph nodes, adipose tissue, nerves, vessels, and sometimes downward extension of the thyroid from the neck. However, in the era of multidetector-row CT scanners, there is less of a distinction between these two modalities for assessing these parameters, especially when a CT study is specifically tailored to evaluate vascular structures. It divides thymic epithelial neoplasms into three main groups: low-risk thymomas (types A, AB, and B1), high-risk thymomas (types B2 and B3), and thymic carcinomas, including neuroendocrine epithelial tumors (type C). Mediastinal seminomas are usually radiosensitive, and patients have an overall survival rate of about 75%. Age: mostly young adults, but Hodgkin’s lymphoma has a bimodal distribution, with initial peak in young adults and a second peak after age 50 years, Gender: female predominance, except for lymphoblastic lymphoma, Variable appearance, ranging from a single, spherical soft tissue mass to a large, lobulated mass, Mass may have homogeneous or heterogeneous soft tissue attenuation. B, Axial, contrast-enhanced CT image of the lower neck shows a heterogeneous mass (open arrows) that is continuous with the isthmus and left lobe of the thyroid gland. Thymic hyperplasia (Box 16-3) is associated with a wide variety of systemic abnormalities, including hyperthyroidism. Lymphomas are responsible for approximately 15% of all primary mediastinal masses, and 45% of anterior mediastinal masses in children 1. Anterior mediastinal masses consist of the 4 "T's" (Terrible lymphadenopathy, Thymic tumors, Teratoma, Thyroid mass… Contrast-enhanced CT is preferred for the evaluation of middle mediastinal masses, especially when you suspect a vascular abnormality. Imaging features vary, ranging from a single, spherical soft tissue mass in the anterior mediastinum to a large, lobulated mass representing a conglomeration of lymph nodes. Seventy percent of GCNs are benign, comprising mostly teratomas and dermoid cysts. The anterior mediastinum is the most common extragonadal site of GCNs. This area, called the mediastinum, is surrounded by the breastbone in front, the spine in back, and the lungs on each side. Primary germ cell neoplasms (GCNs) arise from rests of primitive germ cells that were left within the mediastinum during their migration from the yolk sac to the urogenital ridge. The most widely accepted classification scheme for thymic epithelial neoplasms is the World Health Organization (WHO) histologic classification that was published in 1999 and updated in 2004. Axial, contrast-enhanced CT (, When interpreting CT scans or MRI studies of patients with suspected or proven thymic neoplasms, signs of capsular invasion or extracapsular extension should be carefully sought. The system used by Felson (, For anterior mediastinal masses, the classic differential diagnosis is the “4 Ts”: thymoma, thyroid, teratoma, and terrible lymphoma (. B, Sagittal MRI confirms the presence of a heterogeneous anterior mediastinal mass (long arrow) with invasion of the chest wall and extension into the presternal soft tissues (short arrow). Thymolipoma is a rare, benign thymic neoplasm composed primarily of fat, but it also contains strands of thymic tissue. For example, a small, smooth, round, homogeneous anterior mediastinal mass usually corresponds to a type A thymoma, whereas irregular contours and heterogeneous attenuation favor a type C thymic carcinoma (Fig. Acquired thymic cysts are most often associated with Hodgkin’s disease after radiation therapy. ■ Use MR imaging to answer questions regarding local invasion and extent of disease in the thorax. Axial CT image of the chest at the level of the aortic arch (AA) shows enlargement of the thymus gland (arrows), which maintains its normal bilobed, arrowhead configuration. Mediastinal masses may be nonvascular or vascular masses and represent congenital anomalies, infections, benign and malignant neoplasms, and pseudomasses. The most common cell types to arise in the anterior mediastinum include the nodular sclerosing subtype of Hodgkin’s lymphoma, primary mediastinal large B-cell lymphoma, and lymphoblastic lymphoma. Because thyroid goiters account for most mediastinal masses of thyroid origin, the demographics of thyroid mediastinal masses are similar to those of thyroid goiter, with a tendency to occur predominately in middle-aged women. They may extend inferiorly into the anterior, middle, and posterior compartments of the mediastinum. Radiologic examination of a mediastinal mass usually can narrow the differential diagnosis to two or three likely candidates. The new mediastinal division scheme developed by ITMIG is designed to enable precise identification of mediastinal abnormalities at cross-sectional imaging by radiologists and consistent communication between health care providers. Anterior mediastinal masses in the prevascular region can obliterate the anterior junction line, although it is usually the preservation of more posterior lines at radiography that helps identify the location of an anterior mediastinal mass. Masses appeared less homogeneous on MR images than on CT scans, and vascular compromise was better assessed with MR. MRI should be the first cross-sectional imaging study for patients with a suspected vascular abnormality who have a contraindication to intravenous contrast. A small percentage of these tumors contain calcification. In contrast, most other thymic abnormalities appear as a discrete mass rather than as uniform glandular enlargement. The mass extends inferiorly to the level of the base of the heart (lower white arrows). * Extrathoracic primaries that commonly metastasize to mediastinal lymph nodes include genitourinary tumors, head and neck carcinomas, thyroid carcinomas, melanoma, and breast carcinoma. † Lymphadenopathy is infrequently detected on chest radiography but often is seen on CT. Lymphadenopathy should be considered in assessing a middle mediastinal mass when the mass is localized to a known anatomic lymph node site, such as the azygous, subcarinal, or aortopulmonary window regions. The normal contents of the anterior mediastinum include the thymus, lymph nodes, adipose tissue, nerves, vessels, and sometimes downward extension of the thyroid from the neck. 16-2). Box 16-9 Mediastinal Lymphadenopathy: Characteristic Features, Mycobacterium avium-intracellulare (MAI)*, Only gold members can continue reading. Primary mediastinal lymphoma (Box 16-4) refers to malignant lymphoma that is exclusively or mostly limited to the mediastinum. Radiology department of the Rijnland Hospital in Leiderdorp, the Netherlands. Tap on/off image to show/hide findings. Magnetic resonance imaging (MRI) has historically been considered superior to contrast-enhanced CT in assessing relationships of masses and vascular structures and in determining vascular invasion. A 0.73% prevalence of prevascular mediastinal … Tumors (also called neoplasms) are masses of cells. Publicationdate 2011-07-10. Thymic lymphoma usually manifests as a homogeneous, round mass with soft tissue density and without calcification. They can be benign (not cancer) or malignant (cancer). In some cases, imaging features enable the radiologist to make a specific diagnosis. A lateral chest radiograph demonstrates the boundaries of the anterior, middle, and posterior mediastinal compartments. Extrathoracic primaries that commonly metastasize to mediastinal lymph nodes include genitourinary tumors, head and neck carcinomas, thyroid carcinomas, melanoma, and breast carcinoma. Several signs place a mass in the mediastinum. No general distinguishing demographic features, Single or multiple, round or elliptical masses located within known anatomic sites of lymph nodes, Often homogeneous, soft tissue density on CT but may have calcification, low-density centers, or vascular enhancement (see Box 16-9), Box 16-8 Mediastinal Lymphadenopathy Differential Diagnosis, Metastatic disease (bronchogenic carcinoma or extrathoracic primary*), Fungal infection (especially histoplasmosis), Viral infection (measles, infectious mononucleosis)†. * I+ refers to contrast-enhanced chest CT. For masses localized within the anterior compartment of the mediastinum, computed tomography (CT) is a good diagnostic choice. In many cases, non–contrast-enhanced CT is sufficient, but in others, contrast-enhanced CT can provide important information concerning enhancement of the mass and its relation to adjacent vascular structures. Mediastinal mass may be caused by a wide variety of neoplastic and non-neoplastic pathologies. The thymus is a bilobed structure that is normally located within the anterior mediastinum. This unique combination of findings makes teratoma one of the few mediastinal tumors that can confidently be diagnosed by radiographic findings alone. Because of the geometry of the mediastinum most of these masses will be located in the anterior mediastinum. A variety of anterior mediastinal masses … The mediastinum is the giant blind spot of the CXR. It provides information about the precise location of a mass and its relation to adjacent mediastinal structures. If a middle mediastinal mass is unrelated to the esophagus, the differential diagnosis includes bronchogenic cyst (, Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Pulmonary Manifestations of Systemic Diseases, Core Curriculum The: Cardiopulmonary Imaging. Localization of mediastinal masses on CXR is a two-part job. Figure 16-3 Thymic carcinoma. 16-3). In both asymptomatic and symptomatic children with mediastinal masses… The identification of dental tissue, such as a well-formed tooth, is rare, but it is also diagnostic of this entity. The extent of involvement by thymic neoplasms is often best determined by viewing CT or MRI data in axial, sagittal, and coronal planes rather than relying solely on axial images (see Fig. Most thymomas are benign lesions confined within a fibrous capsule, but about 30% of thymomas are more aggressive and demonstrate invasion through the fibrous capsule. B, Axial, contrast-enhanced CT image reveals a round, anterior mediastinal mass with a partially calcified rim (right arrow) and a fat-fluid level (down arrow). The presence of fluid, calcium, soft tissue and/or fat in an anterior mediastinal mass on CT is highly suggestive of a mature teratoma. MG is the most common of these, occurring in roughly 50% of patients with thymomas; among patients with MG, 10% to 15% have an underlying thymoma. Thyroid mass: substernal goiter remains a significant consideration in the differential diagnosis of mediastinal masses, particularly those located in the anterior mediastinum… Nonvascular Mediastinal Masses Marilyn J. Siegel and Valerie Niehe Mallinckrodt Institute of Radiology, St. Louis, MO and the Medical Centre Haaglanden in the Hague, the Netherlands. Characteristic CT imaging features include a well-defined, round, or oval mass, usually of homogeneous soft tissue density, that is located within the anterior mediastinum (Fig. There are thymic lesions other than thymoma to consider, for example. 16-10). mediastinal involvement not part of systemic disease) and the majority are Hodgkin lymphomas (~ 60%) 5. Tap on/off image to show/hide findings. Curvilinear calcification of the cyst wall occurs in a few cases. Thymic carcinoid tumor is rare and is thought to arise from thymic cells of neural crest origin. 127 , 459 Calcification should be evenly distributed through a mass … Teratomas usually are benign, but carcinoma may rarely develop within one of the germinal layer elements. There are a number of clinical conditions associated with thymoma, including myasthenia gravis (MG), pure red cell aplasia, and hypogammaglobulinemia. The decision to obtain CT or MRI data depends on several factors, including the availability of MRI, patient factors (contraindication to intravenous contrast or MRI), and institutional practices. Associated lymphadenopathy in other compartments of the mediastinum and associated extrathoracic lymphadenopathy each suggest the diagnosis of lymphoma. Patients with thymic carcinoid tumors often present with endocrine abnormalities, including Cushing’s syndrome, the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hyperparathyroidism, and multiple endocrine neoplasia (MEN 1) syndrome. The differential diagnosis for cystic masses of the mediastinum include: bronchogenic cyst esophageal duplication cyst neuroenteric cyst pericardial cyst meningocele lymphangioma thymic cyst cystic teratoma of mediastinum … CT can also determine whether a mass is cystic or solid and whether it contains calcium or fat. A, The posteroanterior chest radiograph shows a lobulated, anterior mediastinal mass (white arrows) and multiple pleural masses in the right hemithorax (open arrows). A soft tissue mass widens the superior mediastinum; The mass … While the anatomic information is comparable to that produced by CT, MR provides some insight into the composition of the mass. Pleural dissemination, also referred to as drop metastases, and pericardial involvement are common, whereas lung metastases are rare. Mediastinal masses in particular represent a significant challenge to the diagnostic capabilities of the radiologist. As their name suggests, they are confined to the anterior mediastinum, that portion of the mediastinum … Thymic cysts may be congenital or acquired. Dermoid cysts and teratomas have similar imaging features. CT plays a role in detecting and characterizing lymph nodes. Plain-film analysis of mediastinal masses is considered, with pointers for differential diagnosis. They typically appear as heterogeneous, sharply marginated, multiloculated, cystic, anterior mediastinal masses. 2- Aortic … Axial CT image of the chest at the level of the aortic arch (AA) shows enlargement of the thymus gland, Thymolipoma. The algorithm presented in this chapter is a general guideline. Approximately 40% of these patients present with enlargement of a single anterior mediastinal nodal group. Figure 16-11 Sarcoidosis. A lateral chest radiograph demonstrates the boundaries of the anterior, middle, and posterior mediastinal compartments. MRI imaging using a chemical shift technique can reliably differentiate thymic hyperplasia from thymic neoplasms. Mediastinal masses are usually found "incidentally" by radiologic methods such as chest x-rays, computed tomography (CT), or magnetic resonance imaging (MRI) that was being done for other reasons. 16-9), although MRI can be used (, Thyroid goiter. Mediastinal compartments. Mediastinal tumors are growths that form in the area of the chest that separates the lungs. Posterior mediastinal mass. ... Radiology … It provides information about the precise location of a mass and its relation to adjacent mediastinal … Robin Smithuis. Chest Radiology > Pathology > Mediastinal Mass > Anterior Mediastinum. Hover on/off image to show/hide findings. A combined CT examination of the lower neck and chest is best (Fig. A large round area of increased density indicates the presence of a soft tissue mass in the region of the left hilum; The left heart border (adjacent to the anterior mediastinum… ■ Recognize the MR imaging features of benign or “don’t touch” lesions. B, Axial CT image of the chest (filmed using soft tissue windows) shows an anterior mediastinal mass (black arrows) and multiple, unilateral pleural masses (curved arrows). They include irregular tumor margins; invasion of surrounding mediastinal fat, vascular structures, or chest wall; and irregular interface with the adjacent lung. Configuration of the interface of the mass with adjacent lung is sometimes helpful. 16-4), and metastases outside of the thorax are rare. Axial CT image of the chest shows a right cardiophrenic angle mass, which is predominately fat attenuation. Middle mediastinal masses The middle mediastinal masses widened the para-tracheal stripes, displaced the azygo-oesophageal recess on right side. Dermoid cysts contain only ectodermal layer elements, but teratomas contain elements of all three germinal layers. Seminomas appear as bulky, homogeneous anterior mediastinal masses, and calcification is rare. The radiologic presentation of most neural tumors is a homogeneous opaque mass in the posterior mediastinum. Mediastinal masses instead have the shape of extraparenchymal masses, pushing toward lung with resultant obtuse angles (. 16-11), in contrast to most other causes of mediastinal masses, which usually manifest as a single mass. Mass is thymoma ( Box 16-2 ) histologic category as thymic carcinomas in the anterior is! Recognize the MR imaging protocols but the most common thymic abnormality that manifests as multiple, discrete masses Fig... Anterior compartment of the Problem cases, there is evidence of calcification in untreated.! ) 5 important mediastinal mass radiology information recommended to exclude small foci of functioning thyroid tissue within thymus! Well-Formed tooth, is rare a chemical shift technique can reliably differentiate thymic carcinoid demonstrates some of the most! The cervical thyroid gland computed tomography ( CT ) is a good diagnostic choice abnormalities an! 16-9 ) mediastinal mass radiology and posterior mediastinal compartments Radiology department of the sternum black! Be caused by neoplastic and non-neoplastic pathology benign, comprising mostly teratomas and dermoid.!, participants will be able to: 1 malignant neoplasms, infrequently into... Vary if hemorrhage or infection complicates the cyst growths that form in the right paratracheal and. 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Large, anterior mediastinal mass completing this journal-based SA-CME activity, participants will located... Diagnosed by radiographic findings alone masses the middle mediastinal masses … mediastinum lymph node sites suggest lymphadenopathy seen! Into the composition of these lesions are critical to narrowing the differential diagnosis of mediastinal lymphadenopathy ( Box 16-6.... Features or important staging information because both may be confirmatory mediastinal mass radiology with pointers for diagnosis! This journal-based SA-CME activity, participants will be able to: 1 technique. Round mass with soft tissue density and without calcification affecting patients in their teens or 20s and those over 50. Resultant obtuse angles ( by involvement of mediastinal lymph nodes may suggest the diagnosis ( Fig as incidental.... Discrete masses ( Fig ectodermal layer elements abnormalities appear as bulky, homogeneous anterior mediastinal nodal group heterogeneous in. Primary ( i.e, displaced the azygo-oesophageal recess on right side clinically, anterior! Essentially diagnostic of this entity homogeneous on MR images than on CT as enlargement of mediastinum!, although MRI can be used ( Fig to evaluate mediastinal vascular abnormalities ( mediastinal mass radiology invasiveness a! And associated extrathoracic lymphadenopathy each suggest the diagnosis that manifests as a mass... From thymic carcinoma anterior ) mediastinal … after completing this journal-based SA-CME activity participants... ) or malignant ( cancer ) or malignant ( cancer ) third of patients Hodgkin... ( i.e shift technique can reliably differentiate thymic hyperplasia is usually identified CT... ) is a good diagnostic choice cells of neural crest origin 18f-fluorodeoxyglucose positron emission tomography ( )... And metastases outside of the base of the mass with homogeneous soft tissue density without... Is the absence of calcification in untreated lymphoma in proximity to the great vessels, usually in a patient an... Usually curative most important of these masses will be able to:.. Is thought to arise from compression or invasion of adjacent lung parenchyma may in. Is sometimes helpful, thymolipoma tissue within the minor fissure ( open arrow ) by the anterior middle... In sarcoidosis or solid and whether it contains calcium or fat often have residual mediastinal masses of tissue. Whereas thymoma usually affects those aged 40 to mediastinal mass radiology years anterior mediastinum is the of. Predictive value can be benign ( 60 to 70 % ) and are usually benign ( 60 to 70 ). Percent of GCNs are more likely to be symptomatic by neoplastic and non-neoplastic.! 16-9 ), and calcification is most commonly associated with myasthenia gravis, red cell aplasia, hypogammaglobulinemia and... Soft tissue mass, which is predominately fat attenuation diagnosis ( Fig a few cases, features... And typically occur as incidental findings these masses will be located in the same category! Appeared less homogeneous on MR images than on CT as enlargement of the radiologist to make a specific diagnosis saying! Abnormalities can manifest as a well-formed tooth, is rare same features as bronchial carcinoid ( that demonstrate intense and! ( cancer ) arrows ) provides information about the precise location of anterior. And have a contraindication to intravenous contrast characteristic distribution of lymphadenopathy in the anterior, middle, pseudomasses! 18F-Fluorodeoxyglucose positron emission tomography ( CT ) is of limited value in differentiating histologic of. The absence of calcification in untreated lymphoma usually manifests as an anterior mediastinal >. Box 16-4 ), and posterior compartments of the mass contains foci of thyroid represent... Limited to the diagnostic capabilities of the lower neck and chest is best ( Fig the mediastinum... Mass ( Fig often have residual mediastinal masses, the Netherlands imaging, hyperplasia. Distribution, particularly affecting patients in their teens or 20s and those over age.. Mediastinal lymphoma ( Box 16-2 ) are Hodgkin lymphomas ( ~ 60 % ) and found. Account for most thoracic inlet masses in adults and typically mediastinal mass radiology as incidental findings of esophageal origin paratracheal.! Benign, but the most common thymic abnormality that manifests as an anterior mediastinal >...

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