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Summary

Representing ~35% of all primary brain tumors, meningiomas are also the most common benign brain tumors. Meningiomas most commonly present in the third and fourth decade of life and are 3 times more common in women than in men. Approximately 90% of meningiomas arise supratentorially, growing from the dural arachnoidal cap cells. Though they very rarely invade brain tissue, they often grow slowly, can get very large before causing neurological symptoms, and are commonly found incidentally on brain imaging. The most common known risk factor is exposure to ionizing radiation. Radiation-induced meningiomas are more likely to have cellular atypia. As far as genetic risk factors are concerned, the most significant is perhaps neurofibromatosis 2 (NF2). About half of NF2 patients have meningiomas and usually they have multiple meningiomas.