Endoscopic evaluation of factors contributing to intrapancreatic biliary stricture in autoimmune pancreatitis.
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.
Hirano
Kenji
K
Department of Gastroenterology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
Tada
Minoru
M
Isayama
Hiroyuki
H
Yamamoto
Keisuke
K
Mizuno
Suguru
S
Yagioka
Hiroshi
H
Yashima
Yoko
Y
Sasaki
Takashi
T
Kogure
Hirofumi
H
Togawa
Osamu
O
Arizumi
Toshihiko
T
Matsubara
Saburo
S
Nakai
Yousuke
Y
Sasahira
Naoki
N
Tsujino
Takeshi
T
Kawabe
Takao
T
Omata
Masao
M
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