title: Endoscopic evaluation of factors contributing to intrapancreatic biliary stricture in autoimmune pancreatitis.
abstract: BACKGROUND
  Intrapancreatic bile duct stricture in autoimmune pancreatitis (AIP) is usually diagnosed as sclerosing cholangitis even if the stricture is limited to the intrapancreatic area. However, it is not known whether compression caused by pancreatic edema or biliary wall thickening causes such a biliary stricture.
  
  
  OBJECTIVE
  Our purpose was to clarify the factor that contributes to intrapancreatic biliary stricture in AIP: pancreatic head lesion or biliary wall thickening.
  
  
  METHODS
  Single-center retrospective study.
  
  
  METHODS
  This study was performed in a tertiary care academic medical center.
  
  
  METHODS
  Fifty-six patients with AIP were included.
  
  
  METHODS
  The relationship between the presence of a pancreatic head lesion and intrapancreatic biliary stricture was examined. In addition, the relationship between the extent of the intrapancreatic biliary stricture and the wall thickening was evaluated.
  
  
  RESULTS
  Among 44 patients with a pancreatic head lesion, 41 (93%) had intrapancreatic bile duct stricture. Among 12 patients without a pancreatic head lesion, only 2 had such a stricture (P < .0001). Intraductal US showed average intrapancreatic biliary wall thickening with severe stricture of 2.7 +/- 1.0 mm, significantly thicker than that with mild stricture (1.9 +/- 0.35 mm; P = .0200).
  
  
  CONCLUSIONS
  Intraductal US was not performed in all patients.
  
  
  CONCLUSIONS
  Both pancreatic edema and biliary wall thickening influenced intrapancreatic biliary stricture in AIP. This type of stricture should be differentiated from extrapancreatic biliary stricture that may be caused by biliary wall thickening only.
authors.affiliation: Department of Gastroenterology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirano
authors.forename: Minoru
authors.initials: M
authors.lastname: Tada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Suguru
authors.initials: S
authors.lastname: Mizuno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yagioka
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yashima
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kogure
authors.forename: Osamu
authors.initials: O
authors.lastname: Togawa
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Arizumi
authors.forename: Saburo
authors.initials: S
authors.lastname: Matsubara
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
authors.forename: Naoki
authors.initials: N
authors.lastname: Sasahira
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tsujino
authors.forename: Takao
authors.initials: T
authors.lastname: Kawabe
authors.forename: Masao
authors.initials: M
authors.lastname: Omata
mesh_terms: D000368:Aged; D001327:Autoimmune Diseases / Q000150:complications*; D003251:Constriction, Pathologic / Q000175:diagnosis / Q000209:etiology; D004724:Endoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000473:pathology*; D010183:Pancreatic Ducts / Q000473:pathology*; D010195:Pancreatitis / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors