The Potential of a Small Melanocytic Lesion to Transform into Choroidal Melanoma: A Retrospective Study and Literature Review

Abstract

Purpose This research aimed to identify critical risk factors for the malignant transformation of small melanocytic choroidal lesions (SMCL) Methods A retrospective longitudinal study was conducted on 218 SMCL cases at the University Hospital of Santiago de Compostela from January 2013 to January 2023. Patients were selected based on their diagnosis of SMCL and their undergoing of comprehensive multimodal imaging such as optical coherence tomography, ultrasonography, and fundus autofluorescence. The primary focus was on evaluating demographic data, symptomatic presentations, and detailed imaging features. Results The cohort consisted of 43% males and 57% females, with a mean age of 69 years. Notably, 19% of the lesions were symptomatic, and 25.5% exhibited orange pigment. Approximately 33% of the tumours were proximate to the optic disc. Multivariate analysis revealed orange pigment presence and a lesion height greater than 2 mm as significant predictors of transformation. The Cox and Snell R-squared coefficient of 0.292 indicated that these factors accounted for about 29.2% of the variability in lesion transformation. The average follow-up period was 52 months, during which 4.6% of the SMCLs evolved into CM. Conclusion This study highlights the substantial role of lesion height exceeding 2 mm and the presence of orange pigment as key risk factors for the transformation of SMCL into CM. These findings are instrumental in aiding clinicians to identify and monitor high-risk patients, enabling early and potentially more effective interventions. Future research is essential to further explore these risk factors and to establish a more comprehensive understanding of SMCL progression to CM.