Characteristics of anterior uveal melanocytomas in 17 cases

Abstract

Objective: To evaluate a case series of anterior uveal melanocytomas (AUMs) for their distinct clinical, histopathologic, and high-frequency ultrasound (UBM) characteristics.

Design: Retrospective single-center case series.

Participants: Seventeen consecutive patients with AUMs.

Methods: Retrospective review of patient, tumor, UBM, histopathologic, and follow-up characteristics. Follow-up data included change in visual acuity, growth, secondary glaucoma, extrascleral extension, or malignant transformation.

Main outcome measures: Tumor, high-frequency ultrasound, histopathologic, and follow-up characteristics.

Results: Seventeen patients had a median follow-up of 20 months (range, 1-130). Tumor was darkly pigmented with nodular configuration in 100% of patients, irregular surface in 82% of patients, characteristic cobblestone surface appearance in 59% of patients, and feathery or fimbriated margins in 88% of patients. Intrinsic vascularity, ectropion uveae, episcleral sentinel vessel, sector cataract, or heterochromia was not seen. High-frequency ultrasound showed high (71%) or moderately high (12%) internal reflectivity in the majority of tumors. Thirteen tumors (76%) involved the iris, 47% of tumors were club-shaped, and 100% of tumors showed no intrinsic vascularity. Mean tumor thickness was 1 mm (standard deviation [SD] ± 0.5, median 0.9, range 0.3-2.1 mm). Mean largest basal dimension was 3.1 mm (SD ± 2.3, median 2.3, range 0.5-9.4 mm) (n=14). Three pathologic evaluations revealed plump polyhedral cells with abundant cytoplasm, small round to oval nuclei, inconspicuous nucleoli, and finely dispersed chromatin. Two tumors had extrascleral extension, 2 tumors were documented to grow, and 1 tumor caused medically controlled glaucoma.

Conclusions: Anterior uveal melanocytomas are uncommon benign melanocytic tumors with characteristic clinical features. High-frequency ultrasound imaging offers excellent views of obscure posterior extent and allows precise tumor measurement and monitoring for growth. It is an invaluable adjunct to digital slit-lamp photography for evaluating tumor stability or growth. This study presents and correlates unique clinical, high-frequency ultrasound and histopathologic characteristics.