Recurrent cystic meningioma.

The authors report a case of recurrent meningothelial meningioma with a large cyst. At the first operation, the mural nodule was totally resected and the cyst wall was removed as much as possible. This cystic tumor recurred six years later at the site where the first operation was performed. Histologically, the cyst wall contained islands of the same neoplastic cells as were previously found in the mural nodule. The authors discuss the preoperative diagnosis and mechanism of cyst formation, and emphasize the importance of complete removal of the cyst wall for permanent cure.