A case of high risk ciliary bidy melanoma arising in an eye after resectioning of an iridociliary melanocytoma

PURPOSE: To report a case of a benign iridociliary melanocytoma recurring as malignant melanoma after excision. METHODS: Observational case report with clinical data, slit-lamp examination findings, ultrasound biomicroscopy results, and histopathological and genetic analyses. RESULTS: A 40-year-old African American woman initially presented with a superonasal iridociliary mass with a maximal thickness of 2.5 mm. Visual acuity of the involved eye was 20/25, intraocular pressure was 52 mmHg on maximal pressure-lowering medications, and Humphrey visual field testing revealed an inferior altitudinal defect. Fine-needle aspiration biopsy and incisional biopsy followed by tumor excision confirmed a benign melanocytoma. After 5 years of stability, possible recurrence was detected on ultrasound biomicroscopy as an increase in ciliary body thickness. The new lesion grew to a thickness of 5.1 mm over the next 18 months of observation. Fine-needle aspiration biopsy and gene expression profile of the recurrent lesion diagnosed a malignant melanoma with high metastatic potential (Class 2). The patient underwent plaque brachytherapy and has ongoing regression of the tumor. CONCLUSION: Transformation of benign iridociliary melanocytoma to melanoma is rare. To the best of the authors' knowledge, this is the first documented case of a melanoma arising in an eye after initial excision of a melanocytoma. Close monitoring of these patients is warranted even years after the initial excision.