Cysts of the Iris Pigment Epithelium. What Is New and Interesting? The 2016 Jose Rizal International Medal Lecture

Purpose: Cysts of the iris pigment epithelium (IPE) can involve the pupillary margin, midzone, or peripheral location or can be free-floating in the aqueous or vitreous or lodged in the anterior chamber angle. Avariant of IPE cyst, known as iris flocculi, can be a marker for systemic thoracic aneurysm.

Design: Review of IPE cysts and description of new observations of the lesions.

Methods: Review of IPE cysts.

Results: Lesions in 672 eyes were classified as of the pupillary margin (n = 49; 7%), midzone (n = 188; 28%), peripheral (n = 424; 63%), or dislodged/free-floating (n = 11; 2%). Cysts of the IPE occurred most often in young adults (21-40 years) (n = 229; 34%) manifesting with peripheral or midzonal cysts. The characteristic clinical features of pupillary margin cyst were teardrop configuration at the pupillary margin, midzonal cyst with fusiform brown appearance, peripheral cyst as iris stromal bulge, dislodged cyst as a brown lesion in the angle, and free-floating cyst with round mass moving by gravitational forces in the aqueous or vitreous. Ultrasound biomicroscopy and anterior segment optical coherence tomography demonstrated the lesions. Surgical intervention for drainage/resection was rarely necessary (<1%). Some (<1%) cysts were associated with iris nevus, iris melanoma, or ciliary body melanoma. Pupillary margin cysts (flocculi) can be found with dissecting thoracic aortic aneurysm, related to genetic mutation in smooth muscle of the iris and aorta.

Conclusions: Cysts of the IPE most often affect the peripheral region (iridociliary) and rarely require intervention. These cysts can be associated with underlying iris or ciliary body nevus or melanoma. Patients with iris flocculi should be monitored for dissecting thoracic aneurysm.