Meningioma: A clinicopathological evaluation

ABSTRACT

As yet no unifying grading system for meningiomas has been adopted. We evaluate epidemiologic factors of meningioma in Iran & degree of agreement between the two commonly used grading systems namely WHO (2000) and Mahmood systems. During a 6-year period 238 meningiomas were selected and reviewed by two independent pathologists using both grading systems. 205(86.1%) cases were benign, 19(8%) atypical and 14(5.9%) malignant. 181(18%) cases were primary and 51(27%) secondary; 35(68%) of the latter benign, 7(14%) atypical and 9(18%) malignant. All intraspinal meningiomas were benign. In benign cranial and spinal types female to male ratios were 1.9 1 and 1.3 1 ; while in atypical and malignant types were 11.4 and 13.1 respectively. Mean ages were 49.9 for benign. 41.1 for atypical and 50 for malignant types. The most frequent site of involvement in all grades of intracranial tumors was cerebral convexity (31.1 %). The most common subtype was menigothelial (65.1%). Female preponderance seen in benign nonrecurrent meningioma became increasingly less prominent and even reversed in recurrent, atypical and malignant forms. Benign recurrent tumors were similar to non-recurrent tumors microscopically. Kappa value comparing two grading systems was 0.947, so good agreements were found between Mahmood and WHO grading systems.