Malignant transformation of an optic disk melanocytoma

To report a case of malignant transformation of an optic disk melanocytoma with a second melanocytoma in the ciliary body.

Clinical data including visual acuity, visual fields, color fundus photographs, fluorescein angiogram, and ultrasonogram and histopathologic studies of this case were reviewed.

The right eye of a 65-year-old white woman was diagnosed with melanocytoma of the optic nerve. Four years later, the tumor became significantly larger. The best-corrected visual acuity declined from 20/40 to counting fingers and the size of the tumor increased fourfold in 2 years. The right globe was enucleated. Histopathologic studies demonstrated moderately pigmented spindle-B malignant melanoma cells adjacent to and within a population of large, polyhedral, heavily pigmented melanocytoma cells that extended to the lamina cribrosa and optic nerve. There was also a deeply pigmented melanocytoma in the ciliary body.

This is a rare case of malignant melanoma transformed from an optic disk melanocytoma. Periodic follow-up of the patient with optic disk melanocytoma is necessary.