Surgical resection of a pineal tumor containing elements of germinoma and astrocytoma.

A 15-year-old boy presented with hydrocephalus due to a pineal tumor presumed to be a germinoma. After a shunting procedure, gross total tumor resection was carried out via an occipital transtentorial approach. Histopathological examination of the tissue demonstrated that, in addition to the expected germinoma, the tumor also contained areas of astrocytoma and areas that, taken in isolation as in a needle biopsy, could have been diagnosed as pineocytoma. The diagnosis and therapy of a pineal tumor of mixed histological types such as this lesion would be seriously compromised by "conventional" empiric radiation and even a stereotactic needle biopsy may not have provided an adequate tissue sample.