The melanocytoma of the optic disc in Korean

Abstract

[한글]

[영문]

Purpose : To report clinical features and natural course of optic disc melanocytoma in Korean. Materials and Methods : We retrospectively reviewed 25 consecutive patients with optic disc melanocytoma. Fundus photographs were used for evaluation of features associated tumor with specific attention to tumor growth. Kaplan-Meier estimate for the probability of tumor growth as a function of time was performed. For analysis of significant factor correlated with tumor growth, univariate analysis using log-rank test and multivariate analysis using Cox proportional hazards regression were conducted. Results : Median age at diagnosis was 46 years with slight female preponderance (64%). All cases were unilateral with equal distribution for each side of the eyes. Median visual acuity was 0.9 in decimal notation and no case showed tumor-related visual loss of 2 Snellen lines or more during follow-up. Median tumor diameter was 3.2mm and median thickness was 1.9mm. Previous series comprised of mainly White and African American patients reported inferotemporal side of the optic disc to be the most commonly occupied area by the tumor, while in our cases with all Asian patients, melanocytoma tends to occupy more superior side of the optic disc, either covering superior half of the optic disc or whole disc area completely. Four cases exhibited tumor enlargement during mean follow-up of 55 months. Using log-rank test, the only significant univariate factor for tumor growth was vascularity within tumor seen on fluorescent angiography (p-value 0.049). Using Kaplan-Meier survival curve, estimated tumor growth was 0% at 1 year, 5% at 2 years, 21% at 5 years, and 60% at 8 years. No cases with tumor growth showed malignant transformation with cytology study. Conclusion : This is the first sizable series of optic disc melanocytoma in Asian patients. Although optic disc melanocytoma generally is considered benign and stationary, it can grow and has been reported to undergo malignant transformation, though in rare cases. Periodic ocular examination of affected patients is imperative.