title: Large, dark lesion on the arm present since birth.
authors.affiliation: University of Calgary Faculty of Medicine, Alberta, Canada. aleung@ucalgary.ca
authors.forename: Alexander K C
authors.initials: AK
authors.lastname: Leung
authors.forename: Alex H C
authors.initials: AH
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D003937:Diagnosis, Differential; D005542:Forearm; D006801:Humans; D008297:Male; D009508:Nevus, Pigmented / Q000151:congenital / Q000175:diagnosis*; D012878:Skin Neoplasms / Q000151:congenital / Q000175:diagnosis*