9539/1 Atypical meningioma


Definitions

Tumours of the central nervous system
ICD-O-3 topography code: C70, C71 and C72

A WHO grade II meningioma histologically characterized by increased mitotic activity or three or more of the following features: increased cellularity, small cells with high nuclear to cytoplasm ratio, prominent nucleoli, uninterrupted patternless or sheet-like growth, and foci of spontaneous or geographic necrosis. Meningiomas with these criteria show a greater tendency to recur 1
 
Louis DN, Ohgaki H, Wiestler OD, Cavenee WK (Eds.)
WHO Classification of Tumours of the Central Nervous System.
4th Edition
International Agency for Research on Cancer: Lyon 2007



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