Abstract
Purpose :
Midzonal iris pigment epithelial (IPE) cysts are typically asymptomatic but can pose a clinical challenge by mimicking ciliary body melanoma. We conducted a case series study of the clinical characteristics of these iris cysts, particularly their shapes and sizes and associated lesions revealed by ultrasound biomicroscopy (UBM).
Methods :
Charts of patients with midzonal IPE cysts encountered by one or more of the authors between April 21, 1976, and September 25, 2017, were reviewed retrospectively. Pertinent demographic information and clinical data about these patients and their cysts were abstracted.
Results :
69 patients with at least one midzonal IPE cyst in at least one eye were identified. At initial diagnosis, patients ranged in age from 14.8 to 89.5 years (median: 66.0 years, mean: 64.3 years). Only one patient in this series was < 30 years old at diagnosis. 38 patients (55.1%) were female. 74 eyes (39 right, 35 left) in this series contained one or more clinically identified midzonal IPE cysts. The cysts involved the right eye alone in 34 patients (49.3%), the left eye alone in 30 patients (43.5%), and both eyes in 5 patients (7.2%). The midzonal IPE cysts were located most often inferotemporally (51.4%) and second most often temporally (23.0%). UBM imaging had been performed on 44 of the 74 affected eyes. The median largest basal diameter of the midzonal IPE cysts evaluated by UBM was 4.5 mm (extremes: 1.5 to 13 mm), and the median depth of these cysts was 1.5 mm (extremes: 0.6 to 6 mm). The largest lesion was a complete ring cyst. All 5 UBM-evaluated eyes that appeared by slit lamp biomicroscopy to have two or more distinct midzonal IPE cysts were shown by UBM to have a single sausage or kidney-bean shaped partial ring cyst with radial folds between the lobules and not separate multiple cysts. UBM imaging also identified peripheral IPE cysts in 32 of 44 evaluated eyes (72.7%). These peripheral IPE cysts were solitary in 6 eyes and multiple in 26 eyes.
Conclusions :
Our case series confirmed previously reported findings regarding age at diagnosis and most common locations of midzonal IPE cysts. However, our UBM images revealed that most multifocal IPE cysts identified by slit lamp biomicroscopy are partial ring cysts with radial folds in the cyst wall between lobules and not true independent multiple cysts and that clinically unsuspected peripheral IPE cysts are frequently associated with midzonal IPE cysts.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.