Choroidal Nevus Growth Into Melanoma in a Young Patient
Know the clinical risk factors for the development of malignancy.
Henry M. Nguyen, BS; Aruba Zafar, MD; Robert J. Medina, BA; and Carol L. Shields, MD
Retina Today 
KEY TAKEAWAYS Uveal melanoma (UM) is the most common primary intraocular cancer in adults, with an annual incidence of 5.1 cases per 1 million individuals in the United States. The three strongest predictors of transformation of a choroidal nevus into UM were found to be tumor thickness > 2 mm on ultrasonography, subretinal fluid on OCT, and orange pigment on fundus autofluorescence. The risk for transformation of a nevus into UM increases sharply with age, becoming nearly 75-times more likely by the eighth decade of life; still, careful monitoring must be guided by objective criteria rather than age alone. Uveal melanoma (UM) is the most common primary intraocular cancer in adults, with an annual incidence of 5.1 cases per 1 million individuals in the United States and a propensity to affect individuals with more lightly pigmented skin.1,2 UM mainly presents in the choroid (90%), with fewer tumors arising in the ciliary body (6%) and iris (4%).3,4 Prognosis worsens when the ciliary body is involved, owing to the greater tumor thickness, greater risk for cytogenetic abnormalities, and higher metastatic potential.5 In one series of 1,059 patients tested for genetic abnormalities, ciliary body tumors demonstrated the highest odds ratio (OR) for chromosome 3 monosomy (OR = 8.17, P < .001) and chromosome 8q gain (OR = 102.87, P = .001), two alterations that are strongly predictive of metastasis.5 Despite advances in local control of UM, approximately 50% of patients develop metastasis, mainly to the liver via hematogenous spread.4,6,7 This persistent risk for systemic spread underscores the need for early detection and structured, risk-based monitoring to improve long-term outcomes. While risk-assessment tools have been published and apply across all ages, nevus transformation into melanoma remains rare in patients under 30 years of age.8-10 In this article, we describe a case of melanocytic growth of a choroidal nevus in a 28-year-old patient, our treatment approach, and the importance of balancing vigilance with measured follow-up in patients of all ages. RISK FACTORS FOR CHOROIDAL NEVUS TRANSFORMATION INTO MELANOMA Careful monitoring must be guided by objective criteria rather than age alone. One widely used framework to standardize the criteria for nevus transformation to melanoma is the mnemonic “To Find Small Ocular Melanoma Doing Imaging” (ie, TFSOM-DIM):11 Thickness > 2 mm (by ultrasonography) Fluid, subretinal (by OCT) Symptoms of VA loss to ≤ 20/50 (by Snellen acuity) Orange pigment (by fundus autofluorescence [FAF]) Melanoma showing acoustic hollowness (by ultrasonography) DIaMeter > 5 mm (by fundus photography) Previous analyses of 1,329 and 1,287 patients with small melanocytic choroidal tumors first highlighted these important features as key predictors of growth and occasional metastasis, with risks compounding when several of these factors were present.12,13 A larger subsequent series of 3,806 patients with choroidal nevus showed that the probability of transformation into melanoma increased when more risk factors were present at the time of diagnosis and over time.11 The 5-year Kaplan-Meier transformation rates were 1% with no factors, 11% with any one factor, 22% with two factors, 34% with three factors, and > 50% with at least four factors.11 The three strongest predictors of transformation of nevus into melanoma included tumor thickness > 2 mm on ultrasonography, subretinal fluid on OCT, and orange pigment on FAF. A smaller effect was noted for symptoms of visual acuity loss on Snellen acuity, melanoma acoustic hollowness on ultrasonography, and tumor diameter > 5 mm on fundus photography.11 In addition to TFSOM-DIM, the MOLES scoring system—Mushroom shape on ultrasonography, Orange pigment on fundus photography and FAF, Large size (≥ 3 disc diameters in base or thickness ≥ 1 mm), Enlarging tumor with growth, and Subretinal fluid on OCT—has been proposed for use by nonspecialists and communities with limited access to advanced imaging techniques in an effort to guide monitoring and referral.14 Despite its good specificity and sensitivity, the accuracy of the MOLES system diminishes for very small tumors.14 These predictive algorithms can help clinicians implement targeted surveillance and timely intervention for patients with one or more high-risk features. CASE REPORT A 28-year-old White man with no ocular melanocytosis was observed with a choroidal nevus in his right eye for 6 years. Initial fundoscopic imaging elsewhere showed a flat pigmented lesion measuring 4 mm x 4 mm in diameter (Figure 1A, arrow) and demonstrated hypoautofluorescence (Figure 1B, arrow).
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