Stereotactic procedures for lesions of the pineal region.

During the 7-year period between June 1985 and May 1992, 34 patients with pineal lesions underwent 66 stereotactic procedures (37 biopsies, 19 third ventriculostomies, 6 cyst aspirations, 3 instillations of 32P into cysts, and 1 insertion of an Ommaya reservoir into a cyst) at the Mayo Clinic. Nine patients subsequently also underwent 10 open resections of lesions of the pineal region. In the 34 study patients, the pathologic entities were 9 gliomas (5 astrocytomas, 2 ependymomas, and 2 oligodendrogliomas), 9 germ cell tumors (7 germinomas, 1 entodermal sinus tumor, and 1 malignant teratoma), 8 pineal parenchymal tumors (3 pinealomas, 3 pinealoblastomas, 1 mixed pinealoma-pinealoblastoma, and 1 intermediate differentiation pineal tumor), 4 other malignant tumors (2 undifferentiated carcinomas, 1 malignant melanoma, and 1 non-Hodgkin's lymphoma), 2 meningiomas, and 2 nonneoplastic lesions (1 glial cyst and 1 inflammatory lesion). No mortality or permanent morbidity was associated with the 66 stereotactic procedures; 2 patients had temporary complications--1 neurologic (transient diplopia) and 1 nonneurologic (pulmonary embolism). Diagnostic tissue was obtained in 33 of the 34 patients. An algorithm for the diagnosis and management of patients with lesions of the pineal region is presented. We conclude that stereotactic biopsy of pineal lesions can be performed safely, has a high diagnostic yield, and facilitates rational planning of treatment.