34. Seminoma

Overview

Staining: HE

Organ: Testis

Description: As with any seminoma is germ cell neoplasia in situ (GCNIS) present. There are two smaller tumor foci and one that is larger. The larger tumor focus is divided by eosinophilic septa, which is responsible for the lobulated macroscopical morphology. The tumor cells are large, show severe atypia and have very bright cytoplasm due to their high glycogen content. The tumor cells are separated by a lymphocytic stroma.

Diagnosis: Seminoma

Causes:

• 30 – 40 year old males

Theory:

Seminomas never contain necrosis. The high glycogen content of the tumor cells make them PAS positive. The conventional (clear cell) renal cell carcinoma has similar-looking cytoplasm, but those tumor cells wouldn’t be PAS positive.

Taken from the encircled area on the overview image. This shows seminiferous tubules filled with large atypical cells, which is characteristic for GCNIS.

From the main tumor, low magnification

From the main tumor, high magnification