Treatment of atypical meningioma.

The aim of this study was to review the outcome after multimodality therapy in atypical meningiomas using the 2000 World Health Organization (WHO) classification system, and to suggest a logical therapeutic approach. Between April 1997 and February 2008, 35 patients with atypical meningiomas were managed in our hospital. All surgical specimens were reviewed according to the 2000 WHO classification system. The median follow-up was 40 months (range: 6-97 months). Radical extirpation surgery (Simpson grade I) was performed in 11 (31%) patients, and there was no tumor recurrence for these patients. For patients who underwent incomplete resection, the median interval to recurrence was increased from 17 months for surgery alone to 39 months for surgery with adjuvant radiation therapy (p=0.138). Age, MIB-l labeling index, and tumor location had no significant effect on either progression-free survival or overall survival. Atypical meningiomas are difficult to manage and have high recurrence and poor survival rates. In our series, complete resection of the tumor is a key determinant for a better outcome. Adjuvant radiation therapy is recommended if incomplete surgical excision is performed.