Clinical and Ultrasound Biomicroscopy Features Associated With Growth in Iris Melanocytic Lesions

Abstract

To determine the clinical and ultrasound biomicroscopy (UBM) features associated with growth in iris melanocytic lesions. Retrospective case series analysis. We included all iris melanocytic lesions that were monitored between January 2005 and November 2009. At the end of the analysis, 44 eyes of 44 patients were included in the final analysis. The clinical features analyzed were: iris color, largest base diameter, radial location of the lesion epicenter, circumferential location of the lesion epicenter, lesion configuration, lesion pigmentation, intrinsic vascularity within the lesion, presence of associated pigmentation, the impact on the pupil, presence of iris atrophy, and lesion-induced localized cataracts. The UBM features included lesion thickness, presence of corneal touch, presence of surface plaque, internal structure, and internal reflectivity. Regression analysis was performed to define the features associated with growth. Twenty-three percent of the lesions showed documented growth. Mean follow-up was 21.4 months (range: 10-48). Clinical features associated with growth were a large basal diameter at baseline (P = .004) and inferior location (P = .004). UBM features associated with growth were: a greater baseline thickness (P = .01), presence of corneal touch (P = .007), an irregular internal structure (P = .0001), and the presence of dots and linear streaks (P < .0001). Clinical features that were not associated with growth were the radial location of the lesion in the iris (P > .999), lesion configuration (P > .999), lesion pigmentation (P > .999), the presence of pigment dispersion (P = .70), iris freckles (P = .15), corectopia (P > .999), ectropion (P > .999), and intrinsic vascularity (P = .70). UBM features not associated with growth were the presence of a surface plaque (P = .07) and the internal reflectivity (P = .77). Substantial growth in iris melanocytic lesions is associated with original larger basal diameter and inferior lesion location. On UBM growth is associated with greater original thickness, presence of corneal touch, and an irregular internal structure. Presence of these features could modify the frequency of observation of those lesions.