Nevus, melanocytoma and melanoma: differential diagnosis

Abstract

SummaryA major analysis on 3680 cases of iris tumors revealed two main types of tumors including solid (79%) and cystic (21%). The most common solid mass was the melanocytic tumor, which included nevus (60%), melanocytoma (3%), and melanoma (26%).Iris nevus is benign. This tumor tends to occur in the inferior portion of the iris. In an analysis of 1611 consecutive eyes with iris nevus, growth into melanoma was documented in 4% at 10 year followup. Statistical analysis for nevus at greatest risk for growth can be remembered by the lettering ABCDEF representing Age (< 40 years), Blood (hyphema), Clock hour inferior, Diffuse configuration, Ectropion, Feathery margins.Iris melanocytoma is benign and appears as a dark brown mass, occasionally with iris and angle seeding. This tumor carries 1% risk for transformation into melanoma.Iris melanoma is malignant and represents 4% of all uveal melanomas. This tumor exhibits slow growth. An analysis of 317 eyes with iris melanoma documented risk for metastasis at 10 years in 9%. Factors predictive of metastasis included extraocular extension and secondary glaucoma.Differentiation and understanding the behavior of these three similar‐appearing tumors is important in their management.