A Rare Case of Primary Anterior Mediastinal Yolk Sac Tumor in an Elderly Adult Male

Figure 3

The fine needle aspiration/core biopsy revealed abundant tumor cells that were pleomorphic with reticular growth pattern. The tumor showed focal reactivity with AFP and CDX2 and focal weak reactivity with TTF-1 and is nonreactive with CK7, CK20, Napsin A, p63, calretinin, CK5/6, D2-40, CD31, PSA, PSAP, synaptophysin, chromogranin, CD56, hepar, CD45, CD5, CD10, and CD30.

(a) H&E stain 20x, insert: 40x

(b) H&E stain 20x

(c) AFP immunostaining, 40x