Ring melanoma of the anterior chamber angle as a mimicker of pigmentary glaucoma.

A 19-year-old man noticed blurred vision in his right eye. He had an intraocular pressure of 60 versus 12 mmHg in the fellow eye. He was initially diagnosed with an atypical, advanced pigmentary glaucoma. The intraocular pressure did not respond to maximal medication, deep sclerectomy, goniopuncture, and 2 cyclophotocoagulations. Sixteen months after presentation, malignancy was first suspected, and the eye was enucleated. A ring melanoma of the anterior chamber angle was confirmed by the histopathologic examination. Normal nuclear staining for breast cancer 1 gene (BRCA1)-associated protein 1 suggested that the tumor was likely of disomy 3 type with a favorable prognosis. No local or systemic recurrence has developed within 4 years. A literature review of this rare type of minimal volume diffuse uveal melanoma identified 18 additional patients. The initial diagnosis in 18 of the 19 patients with a ring melanoma of the anterior chamber angle was unilateral glaucoma with a median intraocular pressure of 40 mmHg and an age range of 16-76 years. Liver metastasis developed in 5 of 12 patients older than 45 years. This rare subtype is estimated to account for 0.05%-0.16% of all uveal melanomas.