title: Infraportal bile duct of the caudate lobe: a troublesome anatomic variation in right-sided hepatectomy for perihilar cholangiocarcinoma.
abstract: OBJECTIVE
  We present our experiences with infraportal bile duct of the caudate lobe (B1) and discuss surgical implications of this rare variation.
  
  
  BACKGROUND
  Although various authors have investigated biliary anatomy at the hepatic hilum, an infraportal B1 (joining the hepatic duct caudally to the transverse portion of the left portal vein) has not been reported.
  
  
  METHODS
  Between January 1981 and December 2005, 334 patients underwent hepatectomy combined with caudate lobectomy for perihilar cholangiocarcinoma. Four of them (1.2%) had infraportal B1 and were investigated clinicoanatomically.
  
  
  RESULTS
  All infraportal B1 were B1l, draining Spiegel's lobe; no infraportal B1r (draining the paracaval portion) or B1c ducts (draining the caudate process) were found. The infraportal B1l joined the common hepatic duct or the left hepatic duct. Three patients underwent right trisectionectomy with caudate lobectomy; for one, in whom preoperative diagnosis was possible, combined portal vein resection and reconstruction were performed before caudate lobectomy to resect the caudate lobe en bloc without division of infraportal B1. For the other 2 patients, the infraportal B1 was divided to preserve the portal vein, and then the caudate lobe was resected en bloc. The fourth patient underwent right hepatectomy with right caudate lobectomy; the cut end of the infraportal B1 showed no cancer by frozen section, so the bile duct was ligated and divided to preserve the left caudate lobe.
  
  
  CONCLUSIONS
  Infraportal B1 can cause difficulties in performing right-sided hepatectomy with caudate lobectomy or harvesting the left side of the liver with the left caudate lobe for transplantation. Hepatobiliary and transplant surgeons should carefully evaluate biliary anatomy at the hepatic hilum, keeping this variation in mind.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Teiichi
authors.initials: T
authors.lastname: Sugiura
authors.forename: Masato
authors.initials: M
authors.lastname: Nagino
authors.forename: Junichi
authors.initials: J
authors.lastname: Kamiya
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishio
authors.forename: Tomoki
authors.initials: T
authors.lastname: Ebata
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Igami
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nimura
mesh_terms: D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D001653:Bile Ducts, Intrahepatic / Q000002:abnormalities* / Q000601:surgery*; D001662:Biliary Tract Surgical Procedures / Q000379:methods; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D005260:Female; D006498:Hepatectomy / Q000379:methods*; D006801:Humans; D008297:Male; D011168:Portal System / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies