Multiple meningiomas consisting of fibrous meningioma and anaplastic meningioma.

A 61-year-old woman presented with progressive dementia over a period of 4 months. Computed tomographic (CT) scans and magnetic resonance (MR) imaging showed 2 meningiomas located at the left parasagittal region and the left sphenoid ridge. These tumors had distinct MRI findings; the left parasagittal tumour showed a clear peritumoral CSF space without brain oedema, but the sphenoid ridge tumour was large with marked peritumoral oedema. Total excision of these 2 tumours was attempted with favourable clinical improvement and histological studies revealed meningiomas of different histological types. The left parasagittal tumour was a fibrous meningioma and the left sphenoid ridge tumour was an anaplastic meningioma with typical brain invasion. These tumours showed a MIB-1 staining index of 1% and 30%, respectively. There was also a difference in the immunohistochemical findings for neurofibromin (NF1 product) expression; the left parasagittal tumour expressed neurofibromin but the left sphenoid ridge tumour lacked neurofibromin expression, suggesting an NF1-gene mutation. This case may be a rare example of the simultaneous occurrence of meningiomas with distinct genotypes.