Long-term follow-up of surgical resection of microcystic meningiomas.

Microcystic meningioma is a rare tumor with myxoid and microcystic features. Our objective was to evaluate the efficacy of surgical resection of microcystic meningioma. Between December 1985 and October 2000 we treated 25 microcystic meningioma patients with surgical resection. We retrospectively analyzed the results including the long-term follow-up of this patient population. We identified 15 women and 10 men with a mean age of 53.8 years (24-76 years) who had microcystic meningiomas treated with surgery. Based on the Simpson grade, we found four Grade I (16%), 16 Grade II (64%), three Grade III (12%) and two Grade IV (8%) resections. The mean preoperative Karnofsky Performance Scale (KPS) score was 80.3 (range 60-100). The mean postoperative KPS score was 90.4 (range 60-100). At a mean follow-up of 101.7 months (range 16-221) the KPS score improved to a mean of 93.8. The recurrence/progression free survival (RFS/PFS) rates at 3 and 5 years were 96% and 88%, respectively. The 3 and 5 year RFS/PFS rates based on the Simpson grade were evaluated. The 3 year RFS/PFS rates for Grade I, II, III and IV were 100%, 100%, 66.6% and 100%, respectively. The 5 year RFS/PFS rates were 66.6%, 90%, 66.6% and 100%, respectively. Microcystic meningioma is a rare tumor, which is characterized by extracellular microcystic spaces filled by edematous fluid and peritumoral edema. Following surgical resection these tumors have a positive prognosis with a benign course. The surgical outcomes seem to be associated with the risks related to the surgical procedure.