Primary iris melanoma: diagnostic features and outcome of conservative surgical treatment

To describe features influencing the management of primary iris melanoma and report the outcome of conservative surgical treatment of patients diagnosed with this condition in a tertiary referral academic setting over a 20 year period.

Retrospective non-comparative case series of consecutive patients diagnosed with iris melanoma from 1980-2000 using medical records from the University of Sydney Department of Ophthalmology and NSW Cancer Registry

51 cases were identified. The most common presentation was growth of a previously noted pigmented lesion. Initial management was either observation or local resection (two had enucleations) with iris reconstruction where possible (23.8%). The mean follow up was 8.7 years (range 1-17 years). Vision of 6/12 or better was maintained in the majority (78.6%) treated by local resection. Pupil reconstruction significantly reduced reported postoperative glare symptoms. Four patients had features suggestive of local recurrence and there was no documented metastatic disease or death from iris melanoma in this series. Histologically, the majority were spindle B cell melanomas. Clinical features including prominent tumour vascularity, rapid growth, and heterogeneous pigmentation were each significantly associated with an epithelioid cell component. Involvement of the iridocorneal angle was frequently associated with ciliary body invasion.

Management decisions for iris melanoma will depend on the clinical features. Mixed or epithelioid histology is more likely in the presence of two or more of the features of malignancy and may justify earlier intervention. When treatment is undertaken, local resection achieves long term tumour clearance with an acceptable morbidity. In resecting iris melanoma, careful assessment for iridocorneal angle involvement is important in treatment planning. Iris reconstruction has a useful role in reducing postoperative photophobia.