Peripapillary choroidal melanomas. Extension along the optic nerve and its sheaths.

We reviewed 26 cases of peripapillary melanoma, 21 (80.8%) of which extended into the optic nerve or its meningeal sheaths. Most melanomas that extended into the optic nerve were necrotic and of the mixed or epithelioid cell type; all invaded the overlying retina and occurred in blind eyes with secondary glaucoma. The extension of melanoma cells into the subarachnoidal space was only influenced by the presence of the melanoma around the optic nerve head (peripapillary). The prognosis of these patients was highly dependent on the presence of orbital extension. A long piece of optic nerve should be excised when eyes with peripapillary melanomas are enucleated.