Intracranial hemangiopericytomas. Angiography, pathology and differential diagnosis.

Intracranial hemangiopericytomas are tumors which angiographically and histologically can mimic other vascular intracranial masses. The term angioblastic meningioma has been applied to this tumor and to other vascular tumors. However, hemangiopericytomas have a unique biological behavior and prognosis as they tend to recur or metastasize and are insensitive to radiation. Hence, the importance of their specific recognition is emphasized. This is a report of the roentgenologic and pathologic fidings in five cases of histologically verified intracranial hemangiopericytomas. The angiographic findings common to these tumors include a myriad of tiny irregular feeding vessels springing from a main trunk, an intense fluffy type of stain, lack of early veins, and prolonged tumor circulation time. The major arterial supply is from the internal carotid or vertebral circulation rather than from external (meningeal) vessels. Differentiation from other vascular tumors particularly supratentorial hemangioblastoma, glioblastoma multiforme, as well as from vascular meningothelial meningioma is important from both the angiographic and histologic aspects.