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A.A. Al–Kandari, B. Fernandes, S. Maloney, C. Edelstien, J. Deschenes, M.N. Burnier, Jr.; Iris Melanoma Originating From an Iris Nevus . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2251.
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© ARVO (1962-2015); The Authors (2016-present)
Iris melanomas represent about 3% of all malignant uveal melanomas. The aim of this study was to describe the clinical presentation, histopathological features and follow up of 9 cases of malignant transformation of iris nevi into iris melanoma managed by iridocyclectomy.
Nine patients presenting with iris melanoma were treated by iridocyclectomy. All patients had previous history of iris nevi and follow up data for each patient was obtained. The period between diagnosis of the iris nevus and the diagnosis of iris melanoma ranged from 4 years to 15 years, with a mean of 9 years. The Best Corrected Visual Acuity (BCVA) in the involved eye at presentation ranged from 20/15 to 20/30 using the Snellen chart. All nine patients underwent iridocyclectomy by different surgeons and the specimens were sent for histopathological evaluation. The margins were checked histopathologically for any tumor involvement and immunohistochemistry was performed for HMB45, S–100 and COX–2.
The ages of the patients ranged from 39 to 81 years, with an average 57.6 years. One patient had diabetes; the others did not have any previous medical history. All patients had history of an iris nevus being diagnosed by an ophthalmologist or they had noticed an iris discoloration themselves in the operated eye. Histopathology and immunohistochemical staining with HMB45 and S–100 of the specimens revealed a diagnosis of malignant iris melanoma in all nine cases. Seven presented with mixed cell type and two with spindle cell type. COX–2 was positive in four of the cases only in the area of malignant transformation. In each case a clear demarcation between the nevi and the malignant melanoma was observed. The follow up period ranged from nine to twelve years post operatively with a mean of 10.1 years with no evidence of recurrence in any of the cases. The final BCVA ranged from 20/20 to no light perception.
We identified nine patients with malignant iris melanoma arising from a previous iris nevus. Given the fact that none of the patients developed recurrence or metastatic lesions, we hypothesise that iris melanoma arising from an iris nevus carry a less malignant phenotype than those arising de novo. Histophathologic examination of iridocyclectomy specimens should be used to examine for the transformed iris nevi and for surgical margins.
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