Clinicopathologic analysis of rhabdoid meningioma.

Rhabdoid meningioma is an uncommon variant of meningioma, and was classified separately for the first time in the 2000 World Health Organization's classification of tumors of the nervous system. Because it often shows malignant histological features and follows an aggressive clinical course, it has been classified as a grade III neoplasm. We describe the clinicopathologic features of 13 patients with this rare tumor. From 13 patients (seven male, six female), 19 specimens of rhabdoid meningioma were obtained between 2001 and 2009. The mean age of patients was 50.4years at their first operation. The mean postoperative follow-up period was 35.7months. Five patients experienced tumor recurrence, and two patients died from the disease. The mean time to first recurrence was 36.1months. The recurrence-free survival rates at 1 and 5years were 62% and 23%, respectively. Immunohistochemically, all tumors were positive for vimentin and epithelial membrane antigen. MIB-1 labeling indices were higher following tumor recurrence. Close follow-up and aggressive treatment of these tumors is warranted.