Primary yolk sac tumor of the cerebellar vermis: a case report.

Extragonadal germ cell tumors are rare and comprise 2-5% of all germ cell tumors. Seminoma/dysgerminoma, teratoma, yolk sac tumor (YST) and mixed germ cell tumors are few of the extragonadal germ cell tumors arising within the brain. Of these, primary pure YSTs arising in the brain are extremely rare and arise in the pineal (62%) and suprasellar (31%) regions. Primary YST occurring in the cerebellum is exceedingly rare, associated with a very poor prognosis and has been reported in less than 10 cases in literature. We herein report a case of primary pure yolk sac tumor in the cerebellar vermis in a 2-year-old child.