Intracranial germ cell tumors in children: an immunohistochemical and electron microscopic study.

From a review of a series of 1,474 intracranial tumors occurring in children, we identified 49 patients (3.3%) with primary intracranial germ cell tumors: 65% germinomatous, 26% nongerminomatous (8 teratomas, 3 endodermal sinus, and 2 choriocarcinomas), and 8 degrees 10 mixed. Placental alkaline phosphatase was present in all germinomas tested. Human chorionic gonadotropin was identified in 7 patients, cytokeratin in 6, and alpha-fetoprotein in 4. The results of immunostaining with antisera against glial fibrillary acidic protein, desmin, and vimentin were essentially negative. Electron microscopy played an important role in confirming the diagnosis in patients with endodermal sinus and mixed tumors. The correct identification of mixed and non-germ-cell tumors requires adequate tumor sampling and proper preparation of tissue for immunohistochemical and electron microscopic examination.