title: Histopathological diagnosis of pancreatic intraepithelial neoplasia and intraductal papillary-mucinous neoplasms: interobserver agreement.
abstract: OBJECTIVE
  The goal of this study was to evaluate the consistency of distinction between pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary-mucinous neoplasms (IPMN) and the hypothesis that guidelines for their distinction might be inadequate.
  
  
  METHODS
  A group of 93 pancreas specimens from surgical resections or autopsies that contained lesions consistent with histopathological diagnoses of PanIN-1A, PanIN-1B, PanIN-2, or IPMN (adenoma or borderline) was collected. The classification of these neoplasms by 6 pathologists, 2 from Europe, 2 from Japan, and 2 from the United States, was compared. The pathologists initially used guidelines current in their practice and then reviewed 47 of the 93 specimens a second time using new consensus definitions and guidelines for PanIN and IPMN that were developed in 2003.
  
  
  RESULTS
  The initial comparison showed frequent disagreement regarding both category and grade of the lesions. Agreement was greater for category than grade. In the second review, agreement among the 6 reviewers improved, remaining higher for category, although disagreements persisted for both category and grade.
  
  
  CONCLUSIONS
  We conclude that the new definitions of PanIN and IPMN improve the consistency in classifying these lesions, but additional work is needed to further improve the reproducibility of their classification.
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA. daniel.s.longnecker@dartmouth.edu
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Longnecker
authors.forename: N Volkan
authors.initials: NV
authors.lastname: Adsay
authors.forename: Carlos
authors.initials: C
authors.lastname: Fernandez-del Castillo
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Hruban
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kasugai
authors.forename: David S
authors.initials: DS
authors.lastname: Klimstra
authors.forename: Günter
authors.initials: G
authors.lastname: Klöppel
authors.forename: Jutta
authors.initials: J
authors.lastname: Lüttges
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Memoli
authors.forename: Tor D
authors.initials: TD
authors.lastname: Tosteson
authors.forename: Akio
authors.initials: A
authors.lastname: Yanagisawa
authors.forename: Robb
authors.initials: R
authors.lastname: Wilentz
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zamboni
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000473:pathology*; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000473:pathology*; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000473:pathology*