Intralesional Vessel Diameter Measured by Optical Coherence Tomography Angiography Could Improve the Differential Diagnosis of Small Melanocytic Choroidal Lesions.

In this study, we aimed to identify the features of indeterminate choroidal melanocytic lesions visualized on optical coherence tomography angiography (OCTA) and to identify the predictors of growth. We retrospectively evaluated 86 patients with indeterminate lesions treated at our centre from 2016 to 2021. Clinical management involved active surveillance followed by brachytherapy if growth was detected. The lesions were classified into two groups according to whether they grew (small melanomas) or remained stable (choroidal nevi). Growth was detected in 19 (22.1%) lesions. All patients underwent OCTA at baseline. These images were compared to identify the possible predictors of growth. Significant between-group differences were observed in thickness ( p = 0.00), greatest basal diameter ( p = 0.00), number of risk factors ( p = 0.00), symptoms ( p = 0.001; relative risk [RR]: 4.3), orange pigment ( p = 0.00; RR: 6.02), and ultrasonographic hollowness (Kappa sign); p = 0.000; RR: 5.3). The melanomas had significantly more vessels with a diameter ≥ 76.3 µm ( p = 0.02; RR: 2.46). The time to growth in these lesions was significantly shorter ( p = 0.05) than in lesions with smaller vessels. These findings show that vessel diameter quantified by OCTA can help differentiate between choroidal nevi and small melanomas, when considered together with clinical risk factors.