title: Malignant transformation of an optic nerve melanocytoma.
abstract: A 47-year-old woman who had had a flat, hyperpigmented lesion of the optic disc and juxtapapillary choroid for at least 17 years experienced acute visual loss. This was caused by rapid growth of a pigmented tumour emanating from the original lesion. Histopathological examination of the enucleated globe revealed a large malignant melanoma originating from a melanocytoma (magnocellular nevus) within the optic nerve and peripapillary choroid. This case represents a very rare instance of malignant transformation of a normally benign tumour.
mesh_terms: D000328:Adult; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D003390:Cranial Nerve Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D005654:Fundus Oculi; D006222:Hamartoma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008544:Melanocytes / Q000473:pathology; D009900:Optic Nerve; D014057:Tomography, X-Ray Computed