The appearances were felt to most likely represent a meningioma, although the very high T2 signal is not typical and suggests a histological variant. The variants that usually are T2 hyperintense are microcystic, secretory, cartilaginous (metaplastic) chordoid and angiomatous.
The patient went on to have surgery.
MICROSCOPIC DESCRIPTION: Paraffin sections show an intensely vascular tumour in which thin-walled vascular spaces of varying calibre are interspersed between small aggregates of cells with round and oval hyperchromatic nuclei and a variable amount of pale cytoplasm. No mitotic figures or areas of necrosis are seen. Attachment to meninges is noted. No evidence of brain invasion is seen. Immunohistochemistry shows strong immunostaining for epithelial membrane antigen (EMA) and vimentin in tumour cells as well as strong nuclear staining for progesterone receptor (PgR) in a moderate number of tumour cells.
FINAL DIAGNOSIS: Angiomatous meningioma.