Eye cancers occur in different parts of the eye and affect various types of cells. Eye cancer can be difficult to diagnose unless a person has regular eye exams. The most common type of eye cancer, retinoblastoma affects mostly children under the age of six, the Merck Manuals Online Medical library states.
Origin
Eye cancer can originate as a primary tumor in the eye or as a secondary tumor, one that spreads, or metastasizes, from other parts of the body. Secondary cancers occur more frequently than primary cancers, the American Cancer Society reports.
Growth
All cancers start when cells, which normally divide only to replace worn out cells, begin to divide rapidly, producing more abnormal cells. Damage to the DNA causes cells to divide abnormally; all the new cells that originate have the same DNA damage and also reproduce wildly.
Cell Types
The most common type of primary cancer of the eye in adults is melanoma, the same type of cancer that often affects the skin. Melanomas develop in melanocytes, cells that produce pigment. Primary intraocular lymphoma has the second highest rate of occurrence, the NCI states.
In children, retinoblastoma, cancer that originates in the cells of the retina, the area of the eye responsible for vision occurs most frequently. Retinoblastomas usually occur because of a genetic mutation that can be inherited or occur as a spontaneous mutation early in embryonic development, the Merck Manuals state. Cancers that spread from other areas most often originate in the breast or lung, according to the same source.
Sites
The most common type of primary cancer of the eye in adults is melanoma, the same type of cancer that often affects the skin. Melanomas develop in melanocytes, cells that produce pigment. Primary intraocular lymphoma has the second highest rate of occurrence, the NCI states. In children, retinoblastoma, cancer that originates in the cells of the retina, the area of the eye responsible for vision occurs most frequently. Retinoblastomas usually occur because of a genetic mutation that can be inherited or occur as a spontaneous mutation early in embryonic development, the Merck Manuals state. Cancers that spread from other areas most often originate in the breast or lung, according to the same source.
Diagnosis
Cancers that develop inside the eyeball can be difficult to diagnose. Most melanomas arise from a nevus, a benign mole, much like a mole found on the skin, which may turn cancerous. Regular eye examinations help diagnose a nevus early so its growth can be checked at regular intervals, the ACS recommends. Retinoblastoma, the most common primary cancer of the eye, causes the center of the eye to look white when a light is shined into the eye or in flash photography.
