A bizarre skin lesion consisting of a collection of brown, hyperkeratotic papules appeared on the thighs of a 51-year-old diabetic man, after repeated insulin injections into the same area over a period of two or more years. The reason for the development of this type of lesion instead of the usual lipodystrophy that follows multiple insulin injections is obscure.
Erickson L, Lipschutz DE, Wrigley W, Kearse WO. A Peculiar Cutaneous Reaction to Repeated Injections of Insulin. JAMA. 1969;209(6):934-935. doi:10.1001/jama.1969.03160190056019