Melanomas of the conjunctiva

Abstract

Conjunctival melanomas are much less common than custaneous melanomas. Consequently, the classification and treatment of these mucosal tumors is more controversial than that of skin tumors. Conjunctival melanomas can be simply classified into tumors that are superficial and develop in a radial-growth phase, and those that are invasive and develop in a vertical-growth phase. By careful histological examination the maximum tumor thickness can be measured and the presence of the tumor within conjunctival epithelium, the substantia propria, or deeper tissues can be determined. Superficial tumors, tumors with a total radial-growth phase, tumors thinner than 0.76 mm., tumors confined to the conjunctival epithelium, and tumors near the corneal limbus seem to have a favorable prognosis. The fact that a conjunctival melanoma arises in an area of acquired melanosis, arises in association with a nevus, or arises de novo has not been definitely proved to be of prognostic significance. Treatment of conjunctival melanomas should be preceded by biopsy and histological confirmation of the diagnosis. Systemic evaluation should include examination of regional lymph nodes, chest roentgenograms, liver scans, and liver function tests. The eye and the complete conjunctival surface should be carefully examined, photographed, and drawn. The commonly accepted treatment of stage I melanomas of the skin or conjunctiva is surgical removal of the malignant tissue. Superficial and minimally invasive tumors near the corneal limbus may sometimes be excised with en bloc resection of the adjacent superficial cornea and sclera. Treatment of any malignant tumor must be somewhat individualized. Melanomas involving the fornices and eyelids may be treated by complete excision or by exenteration. Exenteration seems to be a reasonable plan in patients with extensive or bulky tumors. The role of prophylactic regional node dissection has not been established for patients with conjunctival melanomas. Similarly, adjunctive chemotherapy, immunotherapy, and hormone therapy are of unknown value in the management of stage I tumors of the conjunctiva. Cryotherapy and radiation therapy have been used only in small numbers of patients with conjunctival melanomas. The choice of these treatments instead of surgical excision in the management of such tumors should be highly selective.