Melanocytoma-like growth of a juxtapapillary malignant melanoma.

The case of a 49-year-old woman with a presumed melanocytoma of the right optic disc that grew into a malignant melanoma 7 years after initial diagnosis is presented. When the patient was first examined, the clinical features were typical of a melanocytoma. A marked increase in tumor size during the following years was the only evidence indicating malignant transformation. After 7 years, however, the ophthalmoscopic picture had changed into that of a malignant melanoma, and the eye was enucleated. Histologic examination revealed a choroidal tumor composed mainly of spindle B-type melanoma cells, with infiltration of the overlying retina and optic disc nerve fiber layer.