Possible common origin of alpha-fetoprotein- and human chorionic gonadotropin--secreting cells in intracranial germ cell tumor. Case report.

A primary intracranial germ cell tumor in a 16-year-old boy secreted both alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG). The tumor, located in the right thalamus, contained germinomatous, trophoblastic, and endodermal sinus components. To identify AFP- and HCG-secreting cells, germ cells from the surgical specimen were cultured in vitro. These cultured cells secreted AFP and HCG for 10 weeks, and immunohistochemical studies showed that some of the cells secreted both AFP and HCG. These findings suggest that multipotential germ cells migrate to the encephalic region and may become germ cell tumors containing various types of tissue.