Unilateral Conjunctival-Corneal Argyrosis Simulating Conjunctival Melanoma

clinically misdiagnosed as choroidal melanoma. Currently, most subretinal tumors assumed to be choroidal melanomas are treated with radiotherapy without histological confirmation. The diagnosis of an RPE carcinoma may therefore be missed. Finger et al described a darkly pigmented subretinal tumor accompanied by inflammation that was suspected of being an adenocarcinoma of the RPE. In several published cases, RPE carcinomas were darkly pigmented, but in others, including our case, they were clinically nonpigmented and did not exhibit significant uveitis. Tumors have been located at the posterior pole as well as anterior to the equator. Other clinical features appear to be more useful for the differential diagnosis, including a retinal blood supply of the tumor and extensive yellowish exudates. Both features are rare in choroidal melanoma. The cellular pattern in this case was that of a highly differentiated adenoid tumor. Invasive growth was the criterion for malignancy. There was no evidence of extraocular spread or metastasis. In fact, metastasis has been absent in all welldocumented cases. Extraocular extension has been described by Loeffler et al. To our knowledge, this was the only case that showed no adenoid differentiation but randomly oriented spindle-shaped cells with several mitotic figures. This may represent a more aggressive and invasive form of RPE carcinoma. Tso and Albert as well as Shields et al found that neoplastic RPE proliferations usually develop in otherwise normal eyes. However, in a large proportion of the recently published cases, an RPE carcinoma arose from a juxtapapillary histoplasmosis scar, from a congenital hypertrophy of the RPE, in an eye with phthisis, or in our case from a chorioretinal scar following a subfoveal neovascular membrane. Therefore, it appears likely that reactive proliferation of the RPE plays a role in the pathogenesis of these rare tumors.