Derm Dx: Progressive discoloration of the buttocks

A 53-year-old woman presents with a 3-year history of progressive discoloration of her buttocks. Medical history is negative for systemic disease, and the patient states that a recent chest radiograph was negative. She reports having undergone a cosmetic enhancement procedure to the site several years earlier in the Dominican Republic. The condition is asymptomatic but of cosmetic concern. Examination reveals ...