Overcoming A Diagnostic Dilemma In A Case Of An Anterior Chamber Cyst

Iris cysts are relatively uncommon and can pose a diagnostic challenge due to their similarity to malignant iris and ciliary body tumours. In rare cases, an iris epithelium cyst can dislodge and move into the anterior chamber. The aim of this case presentation is to discuss the clinical features and management of a pigmented, free-floating cyst in the anterior segment 

We report a case of an 18-year-old female who noticed intermittent blurring of vision in her right eye for one and half years. It impacted her quality of life as occasionally she could not see her phone clearly. There was no history of trauma or previous ocular surgery. She is non-vegetarian and owns dogs, cats, rabbits as pets. On examination, the visual acuity in both eyes was 6/5 (Snellen). There was a solitary, central, slightly mobile, pigmented, avascular cyst measuring about 4 x 4.4 mm in the anterior chamber of her right eye. It was noted to be abutting the endothelium centrally and not attached to the iris or the anterior lens capsule. The endothelial cell count in this eye was 3030 cells per square millimetre. There was no inflammation and the intraocular pressure was normal. Anterior segment imaging with OCT, CASIA SS-1000 and UBM (ultrasound biomicroscopy) scans revealed a free-floating anterior chamber cyst with hyper-reflective walls and a clear hypo-reflective lumen. A differential diagnosis of iris pigment epithelial cyst, iris stromal cyst, and parasitic cyst was made. On review after six months, the cyst had shrunk in size to 0.5 x 0.8 mm and was noted to be sitting inferiorly in the angle. It was freely mobile. We performed viscoexpression of the cyst in toto via a small corneal incision. Histopathology concluded that the cyst was benign and derived from the iris pigment epithelium. There was no inflammation post-surgery, and she recovered well. 

This iris cyst affected her quality of life as it intermittently covered her visual axis. Surgery was performed soon after the cyst reduced in size as we were able to easily remove the whole cyst through a small incision. The cyst was derived from the iris pigment epithelium. A combination of clinical examination, diagnostic tools and histopathological evaluation helped in effective management of this case.