title: Proposal for a morphological classification of intraductal papillary neoplasm of the bile duct (IPN-B).
abstract: OBJECTIVE
  We propose a morphological classification of intraductal papillary neoplasm of the bile duct (IPN-B).
  
  
  METHODS
  A retrospective analysis of 16 patients with IPN-B who had undergone surgical resection was conducted. These 16 cases were classified into three types based on the primary lesion's anatomical location: branch duct type (6 cases), main duct type (5 cases) and mixed type (5 cases). In this paper we have analyzed the characteristics of IPN-B according to our new classification.
  
  
  RESULTS
  All branch duct type IPN-B was located in the left lobe and 5 of them were resected by left hepatectomy without extrahepatic bile duct resection (EBDR). On the other hand, all patients with main duct and mixed type IPN-B underwent EBDR in addition to hepatectomy or pancreatoduodenectomy. Microscopically, 2 of 6 patients with branch duct type IPN-B had no malignant component and, in the remaining 4 patients, cancer invasion was restricted to within the ductal wall. There were no cases of branch duct type IPN-B with lymph node metastasis and superficial intraductal tumor spread. In contrast, all patients with main duct and mixed duct type IPN-B had the malignant component. In all cases, lymph node metastasis was not observed, but superficial intraductal tumor spread was frequently found in extrahepatic bile duct lesions: 3 of main duct type and 3 of mixed type. Four patients with superficial intraductal spread had non-curative resection due to a cancer-positive ductal margin. Most patients with IPN-B obtained a good prognosis, but two patients with a cancer-positive ductal margin developed local recurrence.
  
  
  CONCLUSIONS
  Our classification vividly reflects clinical and pathological characteristics of IPN-B and is useful to determine appropriate surgical strategy.
authors.affiliation: Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
authors.forename: Masami
authors.initials: M
authors.lastname: Tabata
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Azumi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Osawa
authors.forename: Masashi
authors.initials: M
authors.lastname: Kishiwada
authors.forename: Takashi
authors.initials: T
authors.lastname: Hamada
authors.forename: Shugo
authors.initials: S
authors.lastname: Mizuno
authors.forename: Masanobu
authors.initials: M
authors.lastname: Usui
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Shuji
authors.initials: S
authors.lastname: Isaji
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000145:classification* / Q000175:diagnosis / Q000601:surgery; D001653:Bile Ducts, Intrahepatic; D002291:Carcinoma, Papillary / Q000145:classification* / Q000175:diagnosis / Q000601:surgery; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods*; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006498:Hepatectomy / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D010193:Pancreaticojejunostomy / Q000379:methods; D011379:Prognosis; D012189:Retrospective Studies