Excision of a large pineal region hemangiopericytoma (angioblastic meningioma, hemangiopericytoma type).

A large hemangiopericytoma was located posterocentrally. The patient presented with headaches and papilledema. Surgical management consisted of total gross excision by a combined right occipital transtentorial and right occipitoparietal transfalcine approach under magnification in three stages over a 6-week period. Removal was aided by dilatation of the right temperooccipital horn ("trapped ventricle") and meningioma-like encapsulation allowed separation of the tumor from the brain and surrounding structures after internal debulking of the tumor. Subsequent peritoneal shunting of the trapped ventricular horn and 5000 rads of radiotherapy were given to the patient. She remains well with an inferior quadrantanopsia on the left side more than 1 year after treatment. Meningiomas of the pineal region, the relationship of meningioma to hemangiopericytoma and malignant mesenchymal tumors (sarcomas) are considered in reference to presumed cells of origin.