PMC8794336_01
Contrast enhanced chest CT at presentation. (A) Axial image at the level of the main pulmonary artery [p] reveals a prevascular mass (white arrows) replacing the left lobe of the thymus with a low attenuation center. (B) There is a dense 2 mm calcification (black arrow) at the periphery of this mass.
med-03-4-f1.jpg
PMC8794336_01_med-03-4-f1.jpg
f1
While the right lobe of the thymus is normal, a mass arises and replaces most of the left lobe (Figure 1A). There is also a 2 mm calcification at the periphery of the lesion (Figure 1B).
Resection specimen of thymic mass. (A) The mass is comprised of cellular lobules with a mixture of large epithelioid neoplastic cells and small thymocytes, intersected by thick fibrous bands. These morphologic features are consistent with a WHO type B2 thymoma. The thymoma invades into surrounding adipose tissue (upper right-hand side). (B) Focally there are only scattered clusters of CK19-positive epithelial cells (arrows) (CK19 immunostaining, insert) which are present at the blue-inked margin (arrowhead). Magnification x40, H&E (A,B).
med-03-4-f2.jpg
PMC8794336_01_med-03-4-f2.jpg
f2
Slides (four slides stained with hematoxylin & eosin) submitted to the ITMIG tumor board showed a lobulated mass that was comprised of cellular lobules that are separated by thick fibrous bands (Figure 2A). In other foci there are scattered clusters of epithelial cells that mark with CK19 without a definite thymocytic component (Figure 2B).
PMC8794336_02