Primary orbital endodermal sinus tumor (yolk sac tumor).

Endodermal sinus tumor, or yolk sac tumor, is the most common malignant neoplasm of germ cell origin and usually occurs in infant testes or ovaries. On rare occasions, the tumor may arise from extragonadal sites, including sacrococcygeal region, uterus, vagina, prostate, retroperitoneum, liver, mediastinum, pineal gland, and third ventricle. The orbit is an unusual location for the primary development of this neoplasm. We report the case of a girl with primary orbital endodermal sinus tumor who was managed with exenteration and chemotherapy with the result of a disease-free survival of 9 years.