Chordoid meningiomas: incidence and clinicopathological features of a case series over 18 years.

Chordoid meningioma (CM) is a rare subtype of meningioma, classified as grade II, which exhibits a high rate of recurrence following subtotal resection. We retrospectively examined nine cases of chordoid meningioma over a case series of 1743 meningiomas (0.52%) operated upon at our institution from 1995 to 2013. All the reported clinicopathological findings were analyzed. Two hundred and twenty-one CM cases have been published to date worldwide and few single-center large case series have been issued. Seventy-five percent of the cases that underwent subtotal resection at our institution had recurrence within 1 year. Total resection of the tumor should be the major objective of surgery to reduce the possibility of tumor recurrence. The percentage of chordoid features within the tumor specimen could assist in predicting the pathogenesis of the lesion. The correlation of the index of proliferation to recurrence rate is still controversial. Much debate exists with regard to the role of adjuvant radiotherapy in CM cases. Immunohistochemical, cytological and ultrastructural studies should be used in combination to assure a correct diagnosis of CM. Owing to the rare occurrence of this meningioma subtype, larger case series are required to assist in providing a reference for diagnosis and to improve the therapeutic management of CM.