Giant granular cell tumor of the suprasellar area: immunocytochemical and electron microscopic studies.

We describe a case of a granular cell tumor (GCT) of the suprasellar region with an 11-year history in a 26-year-old woman. The computed tomographic scan showed a midline, contrast-enhancing, noncalcified mass. The biopsy was diagnosed as GCT. The tumor was treated with radiation therapy. At necropsy, a large, homogeneous GCT surrounded by gliosis was found. The tumor cells were filled with granules positive for periodic acid-Schiff, diastase-resistant. The cells did not contain glial fibrillary acidic protein or S-100 protein. Electron microscopy showed tumor cells filled with innumerable lysosomal structures. No intermediate filament was found within the cytoplasm. The tumor cells were not surrounded by a basement membrane. Based on this study and on our review of the literature, the suggestion that GCT has a multicellular origin is upheld.