RESUMEN
We report two examples of melanin production by human gliomas. One was a grossly pigmented, well-differentiated ependymoma resected from the left frontoparietal region of a 13-year-old girl. The patient received radiotherapy and was free of tumor 12 years after operation. The second example was a pigmented subependymoma incidentally discovered at the autopsy of a 52-year-old man. Neoplastic cells containing an intracytoplasmic pigment satisfying histochemical criteria for melanin were present in both cases. Electron microscopic study of the melanotic ependymoma revealed electron-dense granules in the cytoplasm of cells forming rosettes. Premelanosomes were not detected. While the mechanism of melanogenesis in these cases is obscure, they support the potential of glial derivatives to produce melanin and indicate that melanogenesis in such neoplasms may have no adverse prognostic import.