Conjunctival malignant melanoma

Definition

A rare eye tumor characterized by a flat to nodular conjunctival mass with variable pigmentation. It can arise in any part of the conjunctiva but most often presents on the bulbar surface, near the limbus. Invasion of corneal tissue, eyelid margin, sclera or orbit may occur in advanced tumors. Metastatic spread most commonly involves regional lymph nodes or the lung, liver, and brain. Essential diagnostic criteria are stromal invasion and severe cytological and architectural atypia exceeding those expected in a naevus. Desirable criteria are demonstration of melanocytic markers by immunohistochemistry, pagetoid growth, mitotic activity, invasion into cornea or skin, ulceration, and tumor necrosis.