Melanocytoma is a deeply pigmented variant of melanocytic nevus that classically occurs in the optic disk, sometimes with contiguous involvement of the adjacent retina or choroid. Historically, this tumor was often confused with malignant melanoma both clinically and histopathologically. Today, however, it is generally recognized by its typical clinical features that differ from most melanomas and erroneous enucleation is rarely done. Histopathologically, melanocytoma is composed of intensely pigmented round to oval nevus cells with benign features. Although traditionally believed to be a relatively stationary lesion, it is now known to exhibit minor enlargement in 10–15% of cases and can cause minor visual loss by a variety of mechanisms. In rare instance, it can induce severe visual loss due to spontaneous necrosis of the lesion or compressive optic neuropathy. More importantly, it can exhibit malignant transformation into melanoma in 1–2% of cases. Ophthalmologists should be familiar with melanocytoma of the optic disk and affected patients should be followed periodically.
2Department of Pathology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
Reprint address: Jerry A. Shields, MD, Ocular Oncology Service, Wills Eye Hospital, 840 Walnut Street, Philadelphia, PA 19107.
This manuscript was presented as part of the 2004 Samuel Johnson Memorial Lecture, Jackson MS, June 18, 2004; at the annual meeting of the Macula Society, Las Vegas, Nevada, February 27, 2003; and at the annual meeting of the International Society of Ocular Oncology, Hyderabad, India, January 25, 2004. It was supported by the Eye Tumor Research Foundation, Philadelphia, PA, and by the Award of Merit in Retina Research, Houston, TX (Dr. J Shields), and the Macula Foundation, New York, NY (Dr. C. Shields). The authors reported no proprietary or commercial interest in any product mentioned or concept discussed in this manuscript.
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