Name : Mehrdad
Affiliation : Radiology Department,Masih Hospital,SBMU
Academic Degree: Associate Professor of radiology
Resident : Samira Shahhamzei-Zahra Afravi
Gender : Male
Age : 30
A 30 Y/O man with fever and chills and non productive cough presents to ED . In CXR abnormal mediastinal contour is seen and mediastinal abscess was suspected.
Imaging Procedures and Findings
In CXR mass consolidation is seen in lower right hemithorax which silhouette cardiac and both diaphragmatic shadows . CT scan demonstrated large anterior and middle mediastinal mass with CT density compatible with fatty tissue . There is no evidence of mass effect. Note the cardiophrenic angles, and the anterior mediastinum involvement.(see discussion) Bx was obtained to R/O malignant soft tissue tumors
Mediastinal lipomatosis is a benign, asymptomatic condition characterized by excessive deposition of fat in the mediastinum. Predisposing conditions include obesity, Cushing disease, and corticosteroid therapy. However, this entity is unassociated with identifiable conditions in approximately 50% of patients. On conventional radiographs, the most common finding is smooth, symmetric widening of the superior mediastinum. If the amount of fat deposition is marked, the mediastinum may show lobulated margins. Unlike mediastinal tumor infiltration or hemorrhage, which usually cause tracheal deviation or narrowing, the trachea remains at midline in mediastinal lipomatosis. Fat may also accumulate in the paraspinal regions, chest wall, and cardiophrenic angles; the latter produces enlargement of the epipericardial fat pads that is a clue to the proper diagnosis. CT provides a definitive diagnosis by demonstrating abundant, homogeneous, unencapsulated fat that bulges the mediastinal contours . Displacement or compression of mediastinal structures, particularly the trachea, is notable by its absence. Heterogeneity within the fat suggests other primary or superimposed conditions, such as neoplastic infiltration, infection, hemorrhage, or fibrosis. Multiple symmetric lipomatosis is a rare entity that resembles simple mediastinal lipomatosis radiographically. The distinction between these two conditions is made by the distribution of abnormal fat and mass effect on mediastinal structures. In multiple symmetric lipomatosis, the cardiophrenic angles, paraspinal areas, and the anterior mediastinum are spared; periscapular lipomas may also be seen. The trachea is often compressed or displaced by fat in patients with this condition, whereas this is not seen in simple lipomatosis.
Brant WE, Helms CA. Fundamentals of Diagnostic Radiology, 3rd edition. P410