Malignant meningiomas: a retrospective study of 22 cases.

Malignant (anaplastic) meningioma constitutes a rare subset of meningioma. The aim of the study was to study clinical features and management of malignant meningiomas. Twenty-two patients with malignant meningiomas were surgically treated in our department between January 1986 and January 2005 in Qilu hospital, and we reviewed each patient's clinical records, radiological findings, operative reports, and pathological examinations. Simpson grade I resection was achieved in 16 cases and grade II resection in 6 cases. Postoperative radiotherapy was performed in all patients. No death occurred during the perioperative period in this series. The follow-up period ranged from six months to ten years. Overall 5-year survival and recurrence-free survival estimates were 36.4 and 27.3%, respectively. 16 patients with Simpson Grade I resection had longer median survival times than 6 patients with Simpson Grade II resection (70 months compared with 10 months, p = 0.0001). Only tumor location (p = 0.016) and Simpson grade of surgical resection (p = 0.002) had an impact on outcome according to a Cox regression analysis. Surgical resection and adjuvant radiotherapy are the main treatments for malignant meningiomas, and the degree of tumor removal is the leading factor determining postoperative recurrence and survival.