Suprasellar neoplasm with a granular cell component.

A classification of granular cell lesions of neuropathologic interest is presented along with an unique case in which a suprasellar neoplasm having light and electron microscopic features of a meningioma contained multifocal nests of granular cells which apparently persisted in this tumor over a period of nearly five years. A spectrum of cell differentiation suggested the development of granular cells from small, electron-dense mesenchymal elements having numerous mitochondria. No evidence for a Schwann cell origin was found. It is proposed that the pituitary-hypothalamic axis, where intracranial granular cell nests and granular cell tumors are most common may also give origin to rare mixed neoplasms with a granular cell component.