A case of primary extracranial meningioma of the forearm with bone invasion.

We report here a rare case of primary extracranial meningioma in a 73-year-old woman with an asymptomatic mass located in the left distal-dorsal forearm. MRI revealed the lesion to be poorly circumscribed and unclear, with iso-signal intensity to muscle on T1 and with a relatively high signal intensity on T2-weighted imaging. The histopathology of the specimen from incision biopsy was typical of meningioma, showing bland spindle cell proliferation with a whorling pattern. Immunohistochemically, the tumor cells were positive for epithelial membrane antigen and vimentin, and negative for S-100 expression.