Melanocytoma (magnocellular nevus) of the ciliary body: report of 10 cases and review of the literature

Abstract

Purpose To describe the characteristics of melanocytoma (magnocellular nevus) of the ciliary body, an unusual melanocytic tumor. Design Retrospective, clinicopathologic case series. Methods Ten melanocytomas of the ciliary body were examined histopathologically. Five tumors were also examined by transmission electron microscopy. The clinical histories were abstracted from the patients’ medical records. We compared the clinical, histopathologic, and ultrastructural findings of our 10 cases with those previously reported in the literature. Main outcome measures To define clinical and histopathologic parameters of this rare tumor. Results A total of 40 cases were summarized, including our 10 and 30 previously reported cases. The mean age of the 40 cases was 47 years. Twenty-six patients were female (65%), fourteen were male (35%). No laterality was observed. Eighty percent of the patients were white and 10% were black. The most common clinical presentation was an asymptomatic dark spot involving the iris and ciliary body or the sclera. Involvement of chamber angle structures, with or without intrascleral extension, was observed in 85% (34 of 40 patients); but only 12% (2 of the 17 patients for whom information about intraocular pressure and local extension was available) had elevated preoperative intraocular pressure. By electron microscopy, two distinct cell types were observed. Conclusions Melanocytomas can usually be distinguished from other pigmented lesions of the ciliary body by histopathologic criteria, but may be difficult to differentiate before surgery from other pigmented ciliary body tumors, including malignant melanomas, adenomas, and adenocarcinomas of the pigmented ciliary epithelium. Most tumors can be managed conservatively by iridocyclectomy.