title: A new clinicopathological entity of IgG4-related inflammatory abdominal aortic aneurysm.
abstract: OBJECTIVE
  Recently, the relationship between immunoglobulin (Ig)G4 and idiopathic sclerosing lesions has attracted much attention. IgG4-related disease was first described with regard to the pancreas (autoimmune pancreatitis), and has been expanded to various organ systems. We previously reported that inflammatory abdominal aortic aneurysm (IAAA) could be one of the manifestations of IgG4-related disease. In this study, we tried to elucidate the clinical characteristics of IgG4-related IAAA.
  
  
  METHODS
  This study consisted of 23 cases of IAAA and 40 cases of atherosclerotic abdominal aortic aneurysm (AAA). Clinical presentation, laboratory findings, and pathological features were examined. Aneurysms of 13 cases histologically corresponded to IgG4-related IAAA.
  
  
  RESULTS
  Those cases accounted for 5% of all surgical AAAs, and 57% of IAAAs. Compared to non-IgG4-related IAAA, IgG4-related cases were characterized by less frequent association with abdominal or back pain. Serum IgG4 concentrations were significantly elevated in IgG4-related cases. Interestingly, patients with IgG4-related IAAA frequently showed an allergic constitution, such as drug allergy, autoimmune diseases, high serum IgE concentrations, and a high titer of antinuclear antibody. Pathologically, IgG4-related cases were characterized by more significant thickening of the adventitia and more numerous IgG4-positive plasma cell infiltrations. Three non-IgG4-related cases showed aneurysmal rupture at the time of first presentation, whereas no IgG4-related cases showed rupture.
  
  
  CONCLUSIONS
  Recognizing a new disease entity of IgG4-related IAAA seems important because this was clinically and pathologically different from conventional aAAA and non-IgG4-related IAAA.
authors.affiliation: Department of Pathology, National Hospital Organization, Kanazawa Medical Center, Kanazawa, Japan. sato-kasa@kinbyou.hosp.go.jp
authors.forename: Satomi
authors.initials: S
authors.lastname: Kasashima
authors.forename: Yoh
authors.initials: Y
authors.lastname: Zen
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kawashima
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Endo
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Fuminori
authors.initials: F
authors.lastname: Kasashima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D001019:Aortic Rupture / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D050197:Atherosclerosis / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007249:Inflammation / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000276:immunology; D012185:Retroperitoneal Fibrosis / Q000276:immunology; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D007074:Immunoglobulin G