title: Case of exogenous insulin-derived acanthosis nigricans caused by insulin injections.
abstract: A 73-year-old male with diabetes mellitus had been treated with insulin for six years. He developed a solid mass on his left lateral of the abdomen at the insulin injection site. A firm subcutaneous mass with dark-red erythema was overlaid by dark-brown keratinized plaques. On histological examination of the mass, keratin proliferation and epidermal papilloma were observed. There were four previously reported cases of acanthosis nigricans that were considered to be caused by continuous injections of insulin. Using immunohistochemistry, in our case the findings were positive in the basal epithelial and prickle cell layers when the patient's lesion was dyed with insulin-like growth factor (IGF)-1 antibody. The coexistence of dermal IGF-1 receptor and acanthosis nigricans found in our patient has not been reported previously, to our knowledge.
authors.affiliation: Department of Dermatology, Tokai University Hachioji Hospital, 1838 Ishikawamachi, Hachioji, Tokyo 192-0032, Japan. eiichiro_yahagi@hotmail.com.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Yahagi
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Mabuchi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nuruki
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Manabe
authors.forename: Norihiro
authors.initials: N
authors.lastname: Ikoma
authors.forename: Akira
authors.initials: A
authors.lastname: Ozawa
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Eitaro
authors.initials: E
authors.lastname: Tanaka
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Sekido
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuyama
mesh_terms: D000052:Acanthosis Nigricans / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D006801:Humans; D007279:Injections, Subcutaneous; D007328:Insulin / Q000008:administration & dosage* / Q000009:adverse effects*; D008297:Male; D017526:Receptor, IGF Type 1 / Q000378:metabolism
chemical_list: D007328:Insulin; D017526:Receptor, IGF Type 1