Radiosurgical treatment of recurrent hemangiopericytomas of the meninges: preliminary results.

Hemangiopericytomas of the meninges, classified previously as angioblastic meningiomas, have a propensity to recur either locally or at distant sites within the nervous system after surgical resection. Visceral metastases also develop much more commonly in these lesions than in other types of histologically benign meningiomas. The radiosurgical gamma knife was used to treat five patients with 11 meningeal hemangiopericytomas (seven new, two recurrent, and two residual tumors) after surgical resection of an initially solitary intracranial lesion. Three patients had undergone multiple craniotomies and radiation therapy before referral, and two patients underwent a second radiosurgical procedure for lesions that appeared between 5 and 13 months after the first treatment session. Dramatic tumor shrinkage occurred in most patients within 6 to 10 months after treatment. The only treatment-related morbidity in this series was a partial visual-field defect in one patient with a large falx-tentorial junction hemangiopericytoma who had previously undergone radiation therapy. Radiosurgery appears to cause dramatic early shrinkage of small and medium-sized intracranial hemangiopericytomas that have recurred or developed after previous surgery and/or radiation therapy.