Outcome of Atypical Meningioma

Objective : Limited data are available concerning the outcome of the patients with atypical meningioma due to lack of the studies with large series. The authors review atypical meningioma retrospectively and analyzed various parameters concerning its outcome. Methods : Of the 866 meningioma patients treated between 1990 and 2003, pathologically proven 54 atypical meningiomas were reviewed. Various factors of the patients were analyzed, and surgical specimens were re-examined blindly by neuropathologist without any patient information. Extent of surgical resection was determined according to Simpson's classification by reviewing the chart and postoperative scan if possible. Results : Twenty-three [42.6%] had local recurrences during the follow-up, of which 13 [32.5%] of 40 complete excisions and 10 [71.4%] of 14 incomplete excisions. The median time to recurrence was 47 months, and the overall 3-, 5-, and 10-year local control rates were 62.4%, 41.5%, and 31.1%, respectively. Five [9.3%] died during follow-up period. The mean survival time was 123months, and the overall 3-, 5-, and 10-year survival rates were 94.2%, 87.2%, and 78.5%, respectively. The extent of surgical excision was the most significant prognostic factor not for survival but for local control [p=0.2179 and 0.0005, respectively]. Extracranial metastasis was not seen in our cases. Conclusion : Complete surgical excision is the most important factor in improving local control. Careful long-term follow-up is mandatory because atypical meningioma shows a broad range of aggressiveness and natural history.