Two Late Recurrences of Conjunctival Melanoma.

Purpose: To report a patient who developed two late recurrences of conjunctival melanoma (CoM), of which one occurred after orbital exenteration.

Methods: We describe the case of a patient based on clinical and histopathological examination.

Results: A 52-year-old patient was treated with local excision and cryotherapy for a CoM with primary acquired melanosis (PAM) near the limbus of the right eye. Twenty-one years later, a recurrence developed in the superior fornix of the same eye in an area with widespread PAM; an orbital exenteration was performed. After another 4 years, a painful nodule developed subcutaneously at the inferior margin of the right orbital socket. Pathology showed a recurrence of CoM with a V600K mutation, similar to both of the previous lesions (of 25 and 4 years earlier). The nodule was excised without additional therapy. No recurrences or metastases have been observed in the next 2.5 years. The proposed mechanism for the recurrence after surgery could be via dormant tumor cells that have spread prior to the procedure or via residual intraepithelial malignant melanocytes.

Conclusion: Very late recurrences of CoM are rare but may occur. Our case illustrates the need for long-term awareness of doctors and patients, even after extensive surgical procedures such as orbital exenteration.