Abstract

Yolk sac (endodermal sinus) tumors are rare malignant germ cell tumors that usually arise in the ovary or testis and rarely develop in extragonadal sites. These tumors have often been associated with teratomatous areas. An autopsy case of a mixed malignant germ cells tumor (endodermal sinus tumor and mature teratoma) is reported, in a fourteen-month-old female child. On autopsy, a large protruding mass is located in the sacrococcygeal region, measuring about 15cm in diameter. This tumor mass is invaded into the left side of the gluteus muscle and the left ovary. Multiple metastatic nodules are also demonstrable in the liver. Microscopically, this tumor mass shows reticular areas formed by a loose meshwork lined by flat or cuboidal cells, papillary formations with Schiller-Duval bodies, and solid undifferentiated areas. In some sections, it also reveals various elements derived form trigerm layers, composed of skin appendages, bronchial tree, cartilage, bone and central nervous tissue. Any malignant foci are not seen, within the teratomatous components.