Eye cancer is a general term used to describe many types of tumors that occur in various parts of the eye. It occurs when cells in or around the eye grow abnormally and form a tumor. A tumor may be benign (noncancerous) or malignant (cancerous, meaning cells can spread to other parts of the body). Cancer that forms in the eyeball is called an intraocular malignancy.
Melanoma is the most common type of primary intraocular cancer in adults. It begins when pigmented (colored) cells in the eye called melanocytes grow uncontrollably. Intraocular melanoma is also called uveal melanoma.