When can an eye growth transform into melanoma?

According to a report in the August issue of Archives of Ophthalmology, there are eight factors that may predict whether a choroidal nevus-a benign, flat, pigmented growth inside the eye and beneath the retina-may develop into melanoma.

Carol L. Shields, M.D., and colleagues at Wills Eye Institute, Thomas Jefferson University, Philadelphia, studied the medical records of 2,514 consecutive eyes of patients with choroidal nevi between 1974 and 2006. The tumors had a median (midpoint) diameter of 5 millimeters and a median thickness of 1.5 millimeters at the beginning of the study. Choroidal nevi grew into melanoma in a total of 180 eyes (7 percent) over an average follow-up of 53 months, including 2 percent after one year, 9 percent after five years and 13 percent after ten years.

The factors that predicted growth into melanoma included five previously identified factors: tumor thickness greater than 2 millimeters, fluid beneath the retina, symptoms such as decreased vision or flashes and floaters, orange pigment and a tumor edge within 3 millimeters of the optic disc. Two new factors were also identified: hollowness of the growth on ultrasound and the absence of a surrounding halo, or circular band of depigmentation.

"Until systemic therapies for metastastic uveal melanoma improve, our focus should be on early detection to minimize metastastic disease," the authors write. "All ophthalmologists should participate in this effort and patients with risk factors can be referred for evaluation at centers familiar with the nuances in the diagnosis and management of early melanoma."

Archives of Ophthalmology. 2009;127[8]:981-987.