Intracranial hemangiopericytoma: radiology, surgery, radiotherapy, and outcome in 21 patients.

At operation, 21 meningeal intracranial hemangiopericytomas resembled meningiomas, but differed histologically. They were frequently attached to sinuses, occipitally located, bled profusely at operation, and had a higher risk of recurrence and metastasis. Specific preoperative diagnosis is possible: computed tomography scan showed a meningiomalike tumor, which on the angiogram looked malignant and highly vascular. Two tumors showed a malignant growth pattern on computed tomography scan, "mushrooming." After a radical removal, three patients have lived for more than 10 years without recurrence; two of them were irradiated postoperatively. Three recurrent tumors were treated with radiotherapy only; one responded favorably.