title: Frequency of subtypes of biliary intraductal papillary mucinous neoplasm and their MUC1, MUC2, and DPC4 expression patterns differ from pancreatic intraductal papillary mucinous neoplasm.
abstract: BACKGROUND
  Biliary intraductal papillary mucinous neoplasm (B-IPMN) has been proposed as a unique clinicopathologic disease with distinct histopathologic features, although wide acceptance remains controversial. A recent consensus conference classified pancreatic IPMN (P-IPMN) into 4 subtypes (ie, gastric, intestinal, pancreatobiliary, oncocytic) based on morphologic appearance and mucin (MUC) staining properties. The aim of this study was to determine whether B-IPMN has similar histopathologic and immunologic subtypes to P-IPMN.
  
  
  METHODS
  Specific immunostaining for MUC1, MUC2, and deleted for pancreas cancer, locus 4 were performed on specimens from 19 patients with a histopathologic diagnosis of B-IPMN. Immunostaining patterns of B-IPMN were correlated with histopathology.
  
  
  RESULTS
  Based on histopathology, the following subtypes of B-IPMN were identified: pancreatobiliary n = 9 (47%), intestinal n = 8 (42%), oncocytic n = 2 (11%), and gastric n = 0 (0%). Pancreatobiliary and oncocytic subtypes of B-IPMN were positive for MUC1 and negative for MUC2, and intestinal subtypes were positive for MUC2 and negative for MUC1. Thirteen of the 19 B-IPMN were associated with invasive carcinoma; loss of deleted for pancreas cancer, locus 4 was found in 6 of 13 invasive components and in 3 of 19 noninvasive components of B-IPMN. Five-year survival for patients with resected B-IPMN and invasive carcinoma was 38%, which is similar to that for resected P-IPMN with invasive carcinoma.
  
  
  CONCLUSIONS
  Histopathologic subtypes and type-specific MUC expression patterns of B-IPMN resemble those of P-IPMN. MUC1 expression and/or absence of MUC2 expression, which correlate with aggressive features of P-IPMN, were found in B-IPMN and correlate with invasive B-IPMN. Loss of deleted for pancreas cancer, locus 4 parallels the findings observed in P-IPMN. These findings provide additional support that B-IPMN is a unique entity with similarities to main duct P-IPMN.
authors: Division of Gastroenterologic and General Surgery, Mayo Clinic, Rochester, MN 55905, USA.
authors: Guido M
authors: GM
authors: Sclabas
authors: Joshua G
authors: JG
authors: Barton
authors: Thomas C
authors: TC
authors: Smyrk
authors: David A
authors: DA
authors: Barrett
authors: Saboor
authors: S
authors: Khan
authors: Michael L
authors: ML
authors: Kendrick
authors: Kaye M
authors: KM
authors: Reid-Lombardo
authors: John H
authors: JH
authors: Donohue
authors: David M
authors: DM
authors: Nagorney
authors: Florencia G
authors: FG
authors: Que
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000145:classification* / Q000378:metabolism* / Q000473:pathology; D001661:Biliary Tract Neoplasms / Q000145:classification* / Q000378:metabolism* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000145:classification* / Q000378:metabolism* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000145:classification* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018396:Mucin-1 / Q000096:biosynthesis*; D055262:Mucin-2 / Q000096:biosynthesis*; D010190:Pancreatic Neoplasms / Q000145:classification* / Q000378:metabolism* / Q000473:pathology; D051901:Smad4 Protein / Q000096:biosynthesis*
chemical_list: D018396:Mucin-1; D055262:Mucin-2; C497796:SMAD4 protein, human; D051901:Smad4 Protein