title: Pancreaticobiliary maljunction and biliary cancer.
abstract: Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. Japanese clinical practice guidelines on how to deal with PBM were made in 2012, representing a world first. According to the 2013 revision to the diagnostic criteria for PBM, in addition to direct cholangiography, diagnosis can be made by magnetic resonance cholangiopancreatography (MRCP), 3-dimensional drip infusion cholangiography computed tomography, endoscopic ultrasonography (US), or multiplanar reconstruction images by multidetector row computed tomography. In PBM, the common channel is so long that sphincter action does not affect the pancreaticobiliary junction, and pancreatic juice frequently refluxes into the biliary tract. Persistence of refluxed pancreatic juice injures epithelium of the biliary tract and promotes cancer development, resulting in higher rates of carcinogenesis in the biliary tract. In a nationwide survey, biliary cancer was detected in 21.6% of adult patients with congenital biliary dilatation (bile duct cancer, 32.1% vs. gallbladder cancer, 62.3%) and in 42.4% of PBM patients without biliary dilatation (bile duct cancer, 7.3% vs. gallbladder cancer, 88.1%). Pathophysiological conditions due to pancreatobiliary reflux occur in patients with high confluence of pancreaticobiliary ducts, a common channel ≥6 mm long, and occlusion of communication during contraction of the sphincter. Once the diagnosis of PBM is established, immediate prophylactic surgery is recommended. However, the surgical strategy for PBM without biliary dilatation remains controversial. To detect PBM without biliary dilatation early, MRCP is recommended for patients showing gallbladder wall thickening on screening US under suspicion of PBM.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo, 113-8677, Japan, kamisawa@cick.jp.
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Sawako
authors.initials: S
authors.lastname: Kuruma
authors.forename: Taku
authors.initials: T
authors.lastname: Tabata
authors.forename: Kazuro
authors.initials: K
authors.lastname: Chiba
authors.forename: Susumu
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Satomi
authors.initials: S
authors.lastname: Koizumi
authors.forename: Masanao
authors.initials: M
authors.lastname: Kurata
authors.forename: Goro
authors.initials: G
authors.lastname: Honda
authors.forename: Takao
authors.initials: T
authors.lastname: Itoi
mesh_terms: D001652:Bile Ducts / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D001661:Biliary Tract Neoplasms / Q000209:etiology*; D004108:Dilatation, Pathologic / Q000150:complications / Q000151:congenital; D005706:Gallbladder Neoplasms / Q000209:etiology; D006801:Humans; D010183:Pancreatic Ducts / Q000002:abnormalities* / Q000601:surgery