Fig. 3

Histological examination of surgical specimen. Sections of the bladder tumor reveal a mixed germ cell tumor that is mainly composed of a teratoma with somatic-type malignancy (melanoma and leiomyosarcoma). No immature component is identified. The yolk sac tumor component is only observed in focal areas. The melanoma is composed of sheets of neoplastic cells with melanin pigment, which is demonstrated with Fontana-Masson stain. The melanoma tumor cells are immuno-reactive for S-100, Melan A and HMB-45. The leiomyosarcoma cells are positive for SMA and HHF-35 but nonreactive for h-Caldesmon. a Sheets of melanoma cells with melanin pigment (original magnifications X100). Positive staining for S-100 is noted in both the nuclei and cytoplasm of cells, and the cytoplasm is positive for HMB-45. b Hematoxylin and eosin-stained sections (original magnifications X100) reveal spindle-shaped tumor cells with marked nuclear atypia and frequent mitotic figures (> 10/10 hpf) compatible with leiomyosarcoma (positive for SMA and HHF-35)