Intravitreal invasion of malignant cells from choroidal melanoma after brachytherapy.

We report intravitreal invasion by melanoma cells from a choroidal melanoma after brachytherapy. A malignant melanoma of the choroid with collar-button configuration was treated with iodine 125 brachytherapy. Years later, the collar button developed a dark-chocolate color and began shedding pigmented debris into the vitreous. Coalescence of this debris into spheroidal aggregates suggested the presence of malignant cells; the eye was enucleated. Histologic sections demonstrated a choroidal melanoma with intraretinal and intravitreal invasion by melanoma. Clinical evidence of intraretinal invasion by melanoma cells along with pigmented debris within the vitreous cavity, especially when clustered in spheroidal aggregates, suggests the presence of intravitreal invasion by malignant cells. In this case, intravitreal invasion was verified histologically.