Clinical and Pathologic Characteristics of Biopsy-Proven Iris Melanoma

Objective:Tocollaboratewithmultiplecenterstoidentify representative epidemiological, clinical, and pathologic characteristics of melanoma of the iris. This international, multicenter, Internet-assisted study in ophthalmic oncology demonstrates the collaboration among eye cancer specialists to stage and describe the clinical and pathologic characteristics of biopsy-proven melanoma of the iris. Methods: A computer program was created to allow for Internet-assisted multicenter, privacy-protected, online data entry. Eight eye cancer centers in 6 countries performed retrospective chart reviews. Statistical analysis included patient and tumor characteristics, ocular and angle abnormalities, management, histopathology, and outcomes. Results:Atotalof131patientswithirismelanoma(mean age, 64 years [range, 20-100 years]) were found to have blue-gray(62.2%),green-hazel(29.1%),orbrown(8.7%) irides. Iris melanoma color was brown (65.6%), amelanotic (9.9%), and multicolored (6.9%). A mean of 2.5 clock hours of iris was visibly involved with melanoma, typically centered at the 6-o’clock meridian. Presentationsincludediritis,glaucoma,hyphema,andsectorcataract. High-frequency ultrasonography revealed a largest mean tumor diameter of 4.9 mm, a mean maximum tumor thickness of 1.9 mm, angle blunting (52%), iris root disinsertion (9%), and posterior iris pigment epitheliumdisplacement(9%).UsingtheAmericanJointCommission on Cancer–International Union Against Cancer classification, we identified 56% of tumors as T1, 34% of tumors as T2, 2% of tumors as T3, and 1% of tumors as T4. Histopathologic grades were G1-spindle (54%), G2-mixed (28%), G3-epithelioid (5%), and undetermined (13%) cell types. Primary treatment involved radiation (26%) and surgery (64%). Kaplan-Meier analysisfounda10.7%riskofmetastaticmelanomaat5years. Conclusions: Iris melanomas were most likely to be brownandfoundintheinferiorquadrantsofpatientswith light irides. Typically small and unifocal, melanomas are commonlyassociatedwithanglebluntingandspindlecell histopathology. This multicenter, Internet-based, internationalstudysuccessfullypooleddataandextractedinformation on biopsy-proven melanoma of the iris.