Track

Case Reports

Abstract

Congenital dermal melanocytosis is one of the most encountered newborn pigmented lesions, particularly among patients of darker skin phototypes. However, acquired dermal melanocytosis is very rare with only a handful of cases reported. We present the case of a 14-year-old female with no significant past medical history who developed a blue discoloration of her right hand involving the dorsal aspect of the fourth digit and hand along with the palmar aspect of the fourth and fifth digits. The patient reported that the discoloration was present for several months, but not present since birth, and she denied any associated symptoms such as pain or limited range of motion. A punch biopsy was taken of the dorsal hand, which revealed scattered dermal melanocytes positive for SOX10, MART-1, and HMB45 immunostains, consistent with dermal melanocytosis. The pathogenesis of acquired dermal melanocytosis is unclear. One theory is that abnormal migration of neural crest cells results in quiescent dermal melanocytes that become activated by a trigger, such as UV radiation, chronic inflammation, chemical exposure, or excessive sex hormones. Because acquired dermal melanocytosis is a very rare finding with unclear pathogenesis, it is important to present cases such as this to broaden our knowledge and assist patients in treatment.