Fig. 1.

Microscopic examination and IHC study of tumoral cells (×400).

(A) H&E: Discohesive small round cells arranged as vague rosettes.

(B) CD 99: Positive membranous staining in tumoral cells.

(C) NSE: Positive cytoplasmic staining in tumoral cells.

(D) CD 45: Negative in tumoral cells.

(E) CD 56: Negative in tumoral cells.

(F) CK 7: Positive cytoplasmic staining in surface urothelial cells and negative in tumoral cells.

G- CK 20: Negative in surface urothelial cells and tumoral cells.

H- Synaptophysin: Negative in tumoral cells.

I- Chromogranin: Negative in tumoral cells.