CHOROIDAL NEVUS IMAGING FEATURES IN 3,806 CASES AND RISK FACTORS FOR TRANSFORMATION INTO MELANOMA IN 2,355 CASES: The 2020 Taylor R. Smith and Victor T. Curtin Lecture.

Abstract

To use multimodal imaging for identification of risk factors for choroidal nevus transformation into melanoma. Retrospective chart review of 3806 consecutive choroidal nevi with imaging and 2355 choroidal nevi with additional follow up to identify factors predictive of transformation of choroidal nevus into melanoma. The median patient age was 62.5 years and Caucasian race in 3167 (95%). The choroidal nevus demonstrated median basal diameter of 4.0 mm and thickness of 1.4 mm. Imaging included optical coherence tomography (OCT) showing subretinal fluid (SRF) in 312 (9%), ultrasonography (US) with acoustic hollowness in 309 (9%), and hyper-autofluorescence (AF) in 100 (3%). Of those 2355 choroidal nevi with follow up, Kaplan-Meier estimates of nevus transformation into melanoma at 1, 5, and 10 years were 1.2%, 5.8%, and 13.9%, respectively. Multivariate analysis, using multimodal imaging for detection of factors predictive of nevus transformation into melanoma, included thickness >2 mm on US (hazard ratio (HR) 3.80, p < 0.0001), SRF on OCT as cap over nevus (HR 3.00, p < 0.0001) or SRF ≤3 mm from nevus margin (HR 3.56, p = 0.0003), symptomatic vision loss ≤20/50 on Snellen visual acuity (VA) (HR 2.28, p = 0.005), orange pigment (lipofuscin) hyperautofluorescence on AF (HR 3.07, p = 0.0004), acoustic hollowness on US (HR 2.10, p = 0.0020), and tumor diameter >5 mm on photography (HR 1.84, p = 0.0275). These factors can be recalled by the mnemonic "To Find Small Ocular Melanoma Doing IMaging" (TFSOM-DIM) representing Thickness >2 mm (US), Fluid subretinal (OCT), Symptoms vision loss (VA), Orange pigment (AF), Melanoma hollow (US), and DIaMeter >5mm (photography). The mean 5-year estimates of nevus growth into melanoma were 1% (HR 0.8) for those with 0 risk factor, 11% (HR 3.09) with 1 factor, 22% (HR 10.6) with 2 factors, 34% (HR 15.1) with 3 factors, 51% (HR 15.2) with 4 factors, 55% (HR 26.4) with 5 risk factors, and not-estimable with all 6 risk factors. In this analysis, multimodal imaging was capable of detecting risk factors for nevus transformation into melanoma, including thickness >2 mm (US), fluid subretinal (OCT), symptoms vision loss (Snellen acuity), orange pigment (AF), melanoma hollowness (US), and diameter >5 mm (photography). Increasing number of risk factors imparts greater risk for nevus transformation into melanoma, including thickness >2 mm (US), fluid subretinal (OCT), symptoms vision loss (Snellen acuity), orange pigment (AF), melanoma hollowness (US), and diameter >5 mm (photography). Increasing number of risk factors imparts greater risk for transformation.