Adenoma of the iris pigment epithelium: A report of 20 cases - The 1998 Pan-American lecture

Background: Adenoma of the iris pigment epithelium (IPE) is an uncommon les ion that can simulate iris or ciliary body melanoma, melanocytoma, and pigm ent epithelial cyst. Objectives: To evaluate the clinical and pathological features and prognosi s of adenoma of the IPE in patients managed by us and to elucidate the feat ures that help to differentiate this tumor from iris melanoma and other sim ilar conditions. Patients and Methods: The medical records of 20 patients with adenoma of th e IPE were reviewed, and the clinical and histopathologic features were tab ulated. Results: Ten patients were male and 10 were female, with a mean age of 60.0 years (range, 11-85 years). All patients were referred because of suspecte d iris or ciliary body melanoma. All lesions were solitary and unilateral. Sixteen were located in the peripheral iris; 2, in the midzone; and 2, near the pupillary margin. Clinically, all tumors were abruptly elevated, all b ut 1 were dark gray to black, and all had a smooth, but sometimes multinodu lar, surface. The tumors caused thinning or complete effacement of the over lying iris stroma, but they did not directly involve the stroma. They typic ally blocked light with transillumination. On ultrasound biomicroscopy find ings, adenoma of the IPE shows a solid tumor pattern, sometimes with small cystoid spaces. The tumor was managed by local resection in 2 patients and observation in 18, all of whom have been stable, with follow-up ranging fro m 6 months to 9 years. Histopathologic examination revealed a tumor origina ting in the IPE consisting of cords of pigment epithelial cells separated b y septae of connective tissue. Conclusions: Adenoma of the IPE usually has characteristic features that sh ould differentiate it from iris melanoma, ciliary body melanoma, iris melan ocytoma, and iris cyst. Adenoma of the IPE is a benign tumor that may remai n relatively stable for years.