Congenital bilateral coloboma of iris and choroid accompanied by unilateral multiple primary pigmented iris cysts: A case report

Introduction and importance: Congenital iris and choroidal coloboma is a congenital ocular developmental anomaly, most occur in both eyes, which may exist in isolation or be accompanied by systemic developmental abnormalities. Herein, we report a case of congenital bilateral coloboma of iris and choroid accompanied by unilateral multiple primary pigmented iris cysts. The selection of treatment methods for iris cysts has always been a challenge for ophthalmologists. Especially for primary iris pigment epithelial cysts without clinical symptoms, no particular intervention measures are required. Which in turn helps ophthalmologists to make clinical decisions in real-world practice.

Case presentation: A 16-year-old boy presented to the ophthalmology clinic with a history of poor eyesight in both eyes since childhood. The pupils of both eyes were pear shaped, and there was a pigmented iris cyst about 1.5 mm × 2 mm at 6-7 o'clock pupillary margin of the left eye on slit-lamp examination. A large fan-shaped coloboma of choroid in both eyes respectively, involving the optic nerve and macular area on fundus examination. Ultrasound biomicroscopy revealed three cysts with hyperreflective walls and clear hyporeflective lumen in the left eye, one located on the anterior surface of the iris and the other two located on the posterior surface of the iris. Above all, he had no history of surgery, trauma, infection, tumor or medication. Therefore, primary pigmented iris epithelial cysts were diagnosed. Given that the patient was asymptomatic, with no impact on visual function, his cysts were monitored. After 2 years follow-up, the cysts remained stable.

Clinical discussion: Iris cysts, whether primary or secondary, are a diagnostic and a treatment challenge. Primary iris cysts are mostly present in the iridociliary sulcus and the ciliary crown, often asymptomatic, with a few located forward or larger, manifested as local protrusions around the iris. This patient had no history of ocular surgery or trauma, therefore, combining clinical manifestations and imaging examination results, primary pigmented iris epithelial cysts were diagnosed. For this patient, on the one hand, the surgical risk was high, and iris cysts probably recur after surgery, and there might be no improvement in postoperative visual acuity. On the other hand, the patient's fundus was poor and his family's economic conditions were not good. In addition, the iris cysts of this patient remained stable after 2 years of observation, therefore, no treatment was taken.

Conclusion: Ophthalmologists should be aware of this rare but distinctive presentation, especially in patients without symptoms. Prompt diagnosis and treatment are pivotal in ensuring favorable outcomes and preventing further ocular complications in individuals affected by these uveal anomalies.