Abstract
Abstract: :
Purpose: Malignant melanoma of the eye is rare. The majority of ocular melanomas occur in the uveal tract. While uveal melanoma is the most common primary ocular cancer in adults, it has an annual incidence of only 0.7 per 100,000 persons. However, this tumor carries up to a 50% 5-year mortality rate. Because of the rarity of this disease, a large, single institutional study comparing melanoma markers pertaining to the eye has not been reported. Herein, we describe our analysis of key immunohistochemical markers (S-100, HMB-45, MART-1, tyrosinase{TYR}, and microphthalmia transcription factor{Mitf}) of conjunctival, iris, ciliary body, and choroidal malignant melanomas including tumor cell type (spindle, epithelioid, mixed) when appropriate and reactivity patterns. Methods: 52 ocular melanomas (42 ciliochoroidal {CC}, 8 iris {IR}, 2 conjunctival {CONJ}) were studied. The extent of immunohistochemical reactivity was given as a percentage of the tumor size for each marker. The intensity of staining was graded on a 0-3 scale (0= no staining, 1=weak, 2=intermediate, 3=strong) for S-100, HMB-45, MART-1, and TYR, while Mitf nuclear staining was classified as positive (POS) or negative (NEG). Results: The total number of cases staining for each immunohistochemical marker was as follows: S-100 (CC 42/42{100%}, IR 7/8{88%}, CONJ 2/2{100%}), HMB-45 (CC 42/42{100%}, IR 6/8{75%}, CONJ 2/2{100%}), MART-1 (CC 37/42{88%}, IR 7/8{88%}, CONJ 2/2{100%}), TYR (CC 20/42{48%}, IR 3/8{38%}, CONJ 1/2{50%}), Mitf (CC 32/42{76%}, IR 8/8 {100%}, CONJ 2/2{100%}). The average staining intensity of each immunohistochemical marker was as follows: S-100 (CC 1.1, IR 2.4, CONJ 3.0), HMB-45 (CC 2.0, IR 2.0, CONJ 2.5), MART-1 (CC 1.9, IR 2.4, CONJ 2.5), TYR (CC 1.5, IR 2.0, CONJ 3) Conclusions: Similar to dermal melanoma, in general, S-100 and HMB-45 were the most sensitive ocular melanoma markers. MART-1 and Mitf showed comparable sensitivities for all of these ocular tumors and can be useful additions to the melanoma panel. The conjunctival melanomas stained most intensely followed by the iris melanomas for each immunohistochemical marker. The intensity of staining of the ciliochoroidal melanomas was the weakest. In the intraocular group, the epithelioid cell type stained poorly with TYR.
Keywords: immunohistochemistry • melanoma