Intraocular Melanoma

Intraocular Melanoma

Intraocular melanoma (also called uveal melanoma) although rare, is the most common type of cancer that develops within the eyeball in adults. Melanomas of the skin are much more common than uveal melanomas and develop from pigment-producing cells called melanocytes. When melanoma develops in the eyeball, it is usually in the part of the uvea called the choroid. Choroid cells have the same kind of pigment as melanocytes in the skin, so it is not surprising that these cells sometimes form melanomas. Approximately 90% of intraocular melanomas develop in the choroid.

Nearly all of the remaining 10% of intraocular melanomas are melanomas of the iris. They are the easiest for the patient and doctor to see because they often arise in a pigmented spot on the iris that has been present for many years and then begins to grow. These melanomas usually are relatively slow growing, and they rarely spread to other parts of the body. For these reasons, people with iris melanomas generally have a good prognosis (outlook for survival).

Intraocular melanomas are generally composed of 2 different kinds of cells.

• spindle cells -- These are elongated cells.

• epithelioid cells -- These cells are almost round but with some straight edges.

Most of the tumors are composed of both kinds of cells. The outlook is best if the tumors are mostly spindle cells and worse if they are mostly epithelioid cells. Epithelioid tumors are more likely to metastasize (spread) to distant sites and be fatal. If you have ocular melanoma, your doctor can tell you which type of cells were found.

from: www.cancer.gov