Purpose: To report a clinicopathologic correlation of a melanoma arising from iris component of ocular melanocytosis in a child.
Methods: A 13-year-old boy developed a progressive iris nodule arising from sector iris pigmentation that was a component of congenital ocular melanocytosis involving the iris, ciliary body and choroid. The tumor was examined clinically and with ultrasound biomicroscopy (UBM), removed by peripheral iridocyclectomy, and studied histopathologically.
Results: Clinically, the pigmented nodule was 3 mm in diameter, located within the sector iris pigmentation, and was 2.4 mm in thickness as measured by UBM. Histopathologically, it was composed predominately of spindle B melanoma cells with adjacent spindle and dendritic melanocytes compatible with iris melanocytosis.
Conclusion: Although highly unusual, melanoma can arise in the sector iris pigmentation that is often a component of congenital ocular melanocytosis. Even young patients with ocular melanocytosis should be examined periodically for development of melanoma in the ciliary body and choroid.