Two Cases of Vitiligo Developed on the Persisting Dermal Melanocytosis: Is There a Difference between Epidermal Melanocytes and Dermal Melanocytes?
A 20-year-old woman presented with dermal melanocytic nevus and a one-year history of vitiligo. The patient had a large bluish patch on the right upper back that had been present since birth. There was no significant past medical history and no family history of autoimmune disease. The laboratory studies were unremarkable. Physical examination revealed several white patches on the anterior chest and right scapula. They were partially overlapping the preexisting bluish patch with a faint bluish hue (). Histologically, the overlapping lesion revealed an elongated spindle or dendritic cells containing melanin granules scattered within the dermis. No infiltration of inflammatory cell was observed (). The S-100 protein immunoperoxidase staining was positive in the dermal dendritic cells, and the lesion was devoid of epidermal melanocytes ().