Definition

A rare cancer that begins in the cells that make the dark-colored pigment, called melanin, in the uvea or uveal tract of the eye. The uvea is the middle layer of the wall of the eye and includes the iris, the ciliary body, and the choroid. Intraocular melanoma of the iris is usually a small tumor that grows slowly and rarely spreads to other parts of the body. Intraocular melanoma of the ciliary body and choroid are usually larger tumors and are more likely to spread to other parts of the body. Intraocular melanoma is the most common type of eye cancer in adults. Also called uveal melanoma.