Clinical case--photo essay. Primary cyst of the iris pigment epithelium.

A 25 year old woman was found to have on routine microscopic examination of her right eye a deformation of the iris surface with bulging in the anterior chamber (Figure 1). No lesion was found after wide dilation of the pupil in primary gaze. By adjusting the slip lamp beam to the side and positioning the patient’s eye in far gaze, a smooth slightly pigmented cystic lesion was found (Figure 2). Gonioscopy revealed angle structures obscured by the cyst and lack of lens changes. Ultrasound biomicroscopy (UBM) confirmed the presence of the single echo-free cyst behind the peripheral portion of the iris with focal angle closure (Figure 3). Observation was recommended.