Germ-cell tumors of the diencephalon.

Germ-cell tumors arising in the neuraxis have similar histopathological characteristics to those germ-cell tumors occurring in the gonads and other midline body sites. As a rare cause of intracranial neoplasm, germ-cell tumors affect predominantly the diencephalon and in particular the pineal region and suprasellar structures. Clinical features are due to local infiltration of these areas by tumor and hydrocephalus. Germinomas or mixed-cell tumors with a germinoma component make up the majority of these tumors and are very responsive to irradiation and chemotherapy. Early clinical recognition of a diencephalic tumor and determination of the specific tumor-cell type may result in curative treatment by surgery, irradiation and chemotherapy.