Primary meningeal glioma.

A 59 yr old man presented with headaches and was shown to have a posterior fossa tumor arising from the inferior surface of the tentorium cerebelli. At operation the tumor was discrete from the cerebellum and was thought to be a meningioma. Pathological examination showed the tumor had features similar to those of a meningioma. It consisted of interlacing bundles of spindle cells with a considerable amount of connective tissue. Some mitoses were present. The tumor cells, however, showed abundant staining for glial fibrillary acidic protein indicating their astrocytic nature. The tumor was diagnosed as astrocytoma Grade 2. The tumor 'recurred' 4 mths later and a second surgical removal was attempted. Pathological examination showed features similar to those in the first operative specimen but this time invasion of the cerebellum was present. Deep x-ray treatment (D.X.R.T.) did not alter the tumor growth which proved fatal 7 mths after presentation. The differential diagnosis of an apparently meningeal-based tumor includes the rare entity of primary meningeal glioma. The case is presented as an example of this rare entity which both clinically and pathologically may be mistaken for a meningioma. The prognosis of intracranial solitary primary leptomeningeal gliomas is variable with recurrence and survival being months to years.