By Dena J. Howell, MD, and Sylvia Hsu, MD

A 34-year-old African-American woman came to the clinic with a lesion that had been present on her right shoulder for several years. The lesion had developed spontaneously and was slowly enlarging. As it grew, it became more sensitive and tender to palpation. It was firm with red and brown nodules protruding from a 3-cm erythematous…