Congenital intrastromal epithelial cyst of the iris.

An 18-month-old boy presented with a six-month history of irritation OD. Examination under anesthesia found a 7 mm cyst involving the inferior aspect of the iris OD. There was elevated intraocular pressure, marked injection of the episclera and conjunctiva, and shallowing of the anterior chamber. The cyst was excised. Microscopic examination detected compression of the iris stroma that was caused by an intrastromal cyst lined with nonkeratinizing epithelium forming two layers. Most cystic lesions of the iris that arise during the neonatal period result from separation of the epithelial layers of the iris. In this case, in the absence of trauma, the cyst appeared to have resulted from a developmental inclusion of conjunctival epithelium into the iris stroma.