Grade I meningiomas with atypical characteristics: a worse prognosis.

The study reviewed the histology of cases of grade I meningiomas with spontaneous necrosis, grade I without necrosis and grade I meningiomas, to evaluate the histological and immunohistochemical factors of the patients' prognosis, while correlating the clinicopathological features with the clinical follow-up of the patients. A review of 47 cases from the Department of Pathology of UNIFESP was performed and the samples were submitted to immunohistochemical examination with the p53 protein, Ki-67 cell proliferation factor and progesterone receptor markers. A greater expression was found in the progression of several degrees of aggressiveness for p53 and Ki-67, and a higher frequency of progesterone receptors in the lower degrees. The group of gradelmeningiomas with spontaneous necrosis showed histological and immunohistochemical indexes that approximate those of the grade II meningioma.This suggests a worse prognosis for grade l meningiomas with necrosis.