title: Comparison of histopathological features of pancreatic carcinoma and type 1 autoimmune pancreatitis.
abstract: Type 1 autoimmune pancreatitis (AIP-1) is an immunoglobulin G (IgG)-4-related disease (IgG4-RD), characterized by elevated serum immunoglobulin G4 (IgG4) and infiltration by IgG4(+) plasma cells. Pancreatic carcinoma (PC) sometimes shows infiltration by IgG4(+) plasma cells, but details have been unclear. We compared pathological findings and expression of IgG4 and IgG in fibroses in 18 PC patients to those from 9 AIP-1 patients. Fibroses were divided into areas of ductal adenocarcinoma (DA) and obstructive pancreatitis (OP). Serum IgG4 levels were lower than the cut-off value in all PC patients with no IgG4-RD. Diffuse lymphoplasmacytic infiltration and eosinophil infiltration were characteristic of fibroses in PC. Though AIP-1 samples often had storiform fibrosis even in biopsies, PC did not show storiform fibrosis. Ratios of IgG4(+) plasma cells/IgG(+) plasma cells (IgG4/IgG ratios) in DA and OP were significantly lower than in AIP-1. However, high-density IgG4(+) plasma cell foci were detected in PC fibroses, particularly around peripheral nerves, vessels, and lymphoid follicles; between lobules and invasion fronts; and within neutrophilic abscesses. In conclusion, the IgG4/IgG ratio is useful in distinguishing PC from AIP-1, and should be evaluated in three or more areas, as PC can show localized high-density IgG4(+) plasma cell areas.
authors.affiliation: Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uehara
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hamano
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kawa
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Keiko
authors.initials: K
authors.lastname: Oki
authors.forename: Rie
authors.initials: R
authors.lastname: Nakata
authors.forename: Akira
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Sano
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Ota
mesh_terms: D000368:Aged; D001327:Autoimmune Diseases / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010195:Pancreatitis / Q000473:pathology*; D010950:Plasma Cells / Q000473:pathology
keywords: IgG4+ plasma cell/IgG+ plasma cell ratio; IgG4-related disease; pancreatic carcinoma; type 1 autoimmune pancreatitis