title: Association of IgG4 response and autoimmune pancreatitis with intraductal papillary-mucinous neoplasms.
abstract: OBJECTIVE
  Concurrent intraductal papillary-mucinous neoplasm (IPMN) and autoimmune pancreatitis (AIP) was observed in a patient (index case) at our institution. Cases of coincidental IPMN and type 1 AIP and concurrent ductal adenocarcinoma (PDAC) and AIP have been previously reported. In this study we evaluate the hypothesis that IPMN elicits an IgG4 response.
  
  
  METHODS
  Twenty-one pancreases (including the index case) with IPMN resected at our institution were studied. H&E stained slides were reviewed and blocks of peritumoral pancreas were immunostained with IgG4 to look for IgG4-positive plasma cells.
  
  
  RESULTS
  We found evidence of variable IgG4 overexpression in 4/21 (19%) of IPMN. These included the index case and three others without stigmata of AIP.
  
  
  CONCLUSIONS
  A small subset of pancreatic neoplasms including intraductal papillary-mucinous neoplasms (IPMN) is associated with an IgG4 autoimmune response that sometimes progresses to peritumoral type 1 AIP and less often to diffuse AIP and IgG4-related systemic disease.
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, United States. Electronic address: amin.hedayat@dartmouth.edu.
authors.forename: Amin A
authors.initials: AA
authors.lastname: Hedayat
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, United States.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Lisovsky
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, United States.
authors.forename: Arief A
authors.initials: AA
authors.lastname: Suriawinata
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, United States.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Longnecker
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000150:complications / Q000276:immunology / Q000473:pathology*; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000150:complications / Q000276:immunology / Q000473:pathology*; D002291:Carcinoma, Papillary / Q000150:complications / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000150:complications / Q000276:immunology* / Q000473:pathology
chemical_list: D007074:Immunoglobulin G
keywords: AIP; Autoimmune pancreatitis; IPMN; IgG4; Intraductal papillary-mucinous neoplasm