title: Localized insulin amyloidosis with use of concentrated insulin: a potential complication.
abstract: Insulin-derived amyloidosis is a rare form of amyloidosis composed of insulin fibrils. The pH and concentration of insulin are known to influence the conformational state of the insulin hormone, with an increasing concentration favouring a more complex conformation. Concentrated insulin delivers a large amount of insulin to a localized area, raising the possibility of inducing conformational changes, forming insulin fibrils and leading to localized insulin amyloidosis.
  
  
  
  A middle-aged woman with long history of Type 2 diabetes mellitus, treated with concentrated human insulin (U-500 insulin) presented with nodular lesions at the site of her daily insulin injections. A punch biopsy of the nodules showed skin with dermal amyloidosis staining favourably with Congo Red stain. The amyloid tumours were resected and areas positive for Congo Red stain were sent for liquid chromatography tandem mass spectrometry, which showed a peptide profile consistent with amyloid insulin.
  
  
  
  Concentrated insulin was first introduced in 1952, however, it is only over the last two decades that it has been used increasingly, in congruence with the increasing incidence of obesity and diabetes mellitus seen in the USA. Only a few cases of insulin amyloidosis at the site of injection have been described in literature. With the increase in the use of insulin, this complication seems to be occurring more frequently. This is the first case report of a person with diabetes mellitus who developed localized insulin amyloidosis with the use of concentrated insulin, and points towards a potential complication of developing insulin amyloidosis with the use of concentrated insulin.
authors.affiliation: Department of Internal Medicine, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mangla
authors.affiliation: Department of Pathology, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Kim
authors.affiliation: Division of Hematology/Oncology, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: N
authors.initials: N
authors.lastname: Agarwal
authors.affiliation: Department of Internal Medicine, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: S
authors.initials: S
authors.lastname: Khurana
authors.affiliation: Department of Internal Medicine, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.|Division of Hematology/Oncology, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: R
authors.initials: R
authors.lastname: Catchatourian
authors.affiliation: Department of Pathology, John H. Stroger Jr. Hospital of Cook County, Chicago, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Jiang
mesh_terms: D000686:Amyloidosis / Q000139:chemically induced* / Q000000981:diagnostic imaging; D003924:Diabetes Mellitus, Type 2; D003875:Drug Eruptions / Q000000981:diagnostic imaging / Q000209:etiology*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D007328:Insulin / Q000009:adverse effects*; D008875:Middle Aged; D014057:Tomography, X-Ray Computed
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin