State of the art, nomenclature, and points of consensus and controversy concerning benign melanocytic lesions: outcome of an international workshop.

The following communication summarizes the proceedings of a one-day International Workshop focusing on the histology of benign melanocytic nevi. Areas of controversy identified in 6 focus sessions were the nomenclature and relationships among common nevi including nevi with halo reactions, traumatized nevi, "dysplastic" nevi, and nevi from particular anatomic sites; developmental biology and frequency of malignant transformation associated with congenital nevi; the characterization and biologic nature of atypical spitzoid neoplasms; the basic definition of particular melanocytic cellular phenotypes, and the nomenclature and biologic nature of many candidate blue nevi, combined nevi, and other controversial lesions such as deep penetrating nevus and pigmented epithelioid melanocytoma. Concentrated data collection and follow-up, molecular characterization, and future consensus Workshops may facilitate the resolution of some of these problems. The Group recommended the description of ambiguous or "borderline" lesions as tumors with indeterminate or uncertain biologic/malignant potential. The participants also advised that such lesions at a minimum should be managed by complete excision with clear surgical margins.