Primary Pupillary Margin Cyst of the Iris Pigment Epithelium

Purpose: Description of a patient with a solitary cyst of the pupillary margin iris pigment epithelium (IPE). Methods: A 63-year-old man referred a suspected iris-ciliary body melanoma in his left eye. Based on both clinical examination and ultrasound biomicroscopy, melanoma was considered unlikely. Surgery was undertaken to correct recurrent deterioration of vision due to movement of the lesion across the visual axis. Results: The lesion was excised completely. Ultrasound biomicroscopy and histopathological examination ruled out melanoma and allowed a final diagnosis of primary pupillary margin cyst of the IPE, characterized of pigmented epithelium, with no connective tissue or vessels. No recurrences or fresh lesions appeared during a one-year follow-up. Conclusions: Primary epithelial iris cysts are usually benign. Treatment is required only in symptomatic patients and those with an uncertain diagnosis. Ultrasound biomicroscopy is indispensable to confirm the clinical diagnosis, follow the clinical course and intervene if surgery is required.