Photocoagulation of malignant melanoma

D. Minckler and F. B. Thompson

A 59-year-old woman developed a pigmented, expanding posterior pole choroidal lesion nasally that was clinically consistent with malignant melanoma. She refused enucleation, but agreed to a trial of photocoagulation therapy. Four weeks after photocoagulation, a reaccumulation of pigmentation and apparent elevation prompted a second photocoagulation treatment. During the second photocoagulation episode corneal edema occurred, and thereafter the fundus view was poor. Again, four weeks after the second treatment there appeared to be increasing pigmentation and possible elevation in the lesion centrally. Because of apparent continued growth of the tumor, the globe was enucleated 82 days after the initial photocoagulation. Serial section histopathologic examination of the lesion revealed only rare neoplastic cells along the base of the lesion. However, myriad pigment-laden macrophages were present around a central area of necrosis. Pigment accumulation within macrophages had simulated tumor growth clinically.