Chordoid meningioma: a clinicopathologic study of 11 cases at a single institution.

Chordoid meningioma is an uncommon variant of meningioma, which histologically bears a great resemblance to chordoma and often follows an aggressive clinical course. We examine clinicopathologic features of 11 cases of this rare tumor to further elucidate its behavior. Thirteen specimens of chordoid meningioma belonging to 11 patients were obtained at a single institution from 1995 to 2009. Correlations of histologic parameters, immunohistochemical study, and clinical features were assessed. This series included six men and five women with a mean age of 60.8 years at first surgery. Aside from one patient (case 5) who died of disease immediately after the first operation, the mean postoperative follow-up period for the other 10 patients was 41.4 months. Two patients each had a local tumor recurrence. The mean time to recurrence was 10.4 years. No systemic manifestations of Castleman syndrome, such as iron-refractory hypochromic/microcytic anemia and dysgammaglobulinemia, were found. Six tumors (46%) were classified as benign (grade I) and seven tumors (54%) atypical (grade II), if based solely on histologic grading irrespective of chordoid or clear cell components in our cases. Lymphoplasmacytic infiltrate was moderate in one tumor (7%), mild in eight tumors (62%), and absent in four tumors (31%). The inflammatory cells were predominantly T cells (CD3+), with only scarce B cells (CD20+). There was a wide range of MIB-1 labeling indices (0.3-25.8%, mean 7.5%), which increased following tumor recurrence. Our study demonstrates that chordoid meningiomas are not always associated with Castleman's Syndrome, and that this histologic category can be seen in the elderly as opposed to only in younger age groups.