Melanotic medulloblastoma. Report of a case with ultrastructural findings.

A pigmented neoplasm of the cerebellar vermis in a four year old child was typical of differentiating medulloblastoma with islands of epithelial-like cells containing melanin pigment. There have been several previous reports of such melanotic cerebellar neoplasms. Reported cases have had a clinically malignant behavior with dissemination in the central nervous system. They appear to be variants of medulloblastoma and not pigmented neuroectodermal tumors of infancy (melanotic prognomas or retinal anlage tumors). Ultrastructurally the neoplasm was compatible with medulloblastoma with focal poorly differentiated cells which contained melanin pigment. The pigment resembled neural crest (cutaneous or ocular) melanin rather than neuromelanin.