Choroidal malignant melanoma with early vitreous seeding.

Primary choroidal malignant melanoma with extension through the overlying retina is a rarely reported entity, and to our knowledge actual seeding of the vitreous has never been reported. The pathologic findings in a 41-year-old woman who presented with a large amelanotic subretinal mass near the optic disc of the right eye are discussed. Fundus examination preoperatively revealed a concentration of discrete, fleshy, oval to round, vitreous bodies of varying size, limited to the area overlying the mass. Histopathology of this tumor revealed a spindle cell posterior choroidal melanoma with marked atrophy of the overlying retina. At the apex, the retina was discontinuous and melanoma cells extended into the overlying vitreous. Some of the cells surrounded asteroid bodies overlying the tumor, altering their clinical appearance. This behavior, while only involving a small fraction of the tumor cells, may imply a more aggressive tumor.