Imaging Manifestations of Mediastinal Fat Necrosis
Axial (a) and oblique (b) unenhanced chest CT (soft tissue window) shows an ovoid lesion (arrow) of heterogeneous fat attenuation with intrinsic soft tissue stranding in the inferior aspect of the right major fissure. The lesion is surrounded by a thick rim of soft tissue attenuation. (c) Low power photomicrograph (hematoxylin & eosin [H&E] stain; original magnification 40x) shows lobules of adipose tissue surrounded by a fibrous pseudocapsule (arrow) and adjacent atelectatic lung parenchyma (*). (d) High power photomicrograph (H&E stain; 400x) shows fat necrosis and lipid laden macrophages (arrowhead).