title: Intraductal papillary mucinous neoplasm of the pancreas and IgG4-related disease: a coincidental association.
abstract: OBJECTIVE
  Coexistence of autoimmune pancreatitis (AIP) and pancreatic cancer, elevation of serum IgG4 levels in pancreatic cancer patients, and infiltration of IgG4-positive plasma cells in peritumorous pancreatitis have been described in a few reports. This study examined the relationship between intraductal papillary mucinous neoplasm (IPMN) of the pancreas and peritumorous IgG4-positive lymphoplasmacytic infiltrates.
  
  
  METHODS
  Serum IgG4 levels were measured in 54 patients with IPMN (median 70 years, 26 males and 28 females; 13 main duct type and 41 branch duct type). Histological findings focusing on dense lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis were reviewed, and immunostaining with IgG4 and IgG was performed in 23 surgically resected IPMN cases (18 main duct type and 5 branch duct type). The presence of IgG4-positive plasma cells >10/hpf and an IgG4-positive/IgG-positive plasma cell ratio >40% were considered significant.
  
  
  RESULTS
  Serum IgG4 levels were elevated in 2 (4%) IPMN patients. Significant infiltration of IgG4-positive plasma cells was detected in 4 IPMN cases (17%). The IgG4-positive/IgG-positive plasma cell ratio was >40% in all 4 cases. In one case with a markedly elevated serum IgG4 level (624 mg/dL), typical lymphoplasmacytic sclerosing pancreatitis (AIP type 1) lesions surrounded the whole IPMN. In the 3 other cases, infiltration of IgG4-positive plasma cells with fibrosis was focally detected mainly in the periductal area around the IPMN.
  
  
  CONCLUSIONS
  In a few patients with IPMNs, IgG4-positive plasma cell infiltration can occur in the peritumorous area. The association of an IPMN with AIP type 1-like changes seems to be exceptional and coincidental.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8677, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Tabata
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Hara
authors.forename: Sawako
authors.initials: S
authors.lastname: Kuruma
authors.forename: Kazuro
authors.initials: K
authors.lastname: Chiba
authors.forename: Go
authors.initials: G
authors.lastname: Kuwata
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Hideto
authors.initials: H
authors.lastname: Egashira
authors.forename: Satomi
authors.initials: S
authors.lastname: Koizumi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Endo
authors.forename: Koichi
authors.initials: K
authors.lastname: Koizumi
authors.forename: Junko
authors.initials: J
authors.lastname: Fujiwara
authors.forename: Takeo
authors.initials: T
authors.lastname: Arakawa
authors.forename: Kumiko
authors.initials: K
authors.lastname: Momma
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Horiguchi
authors.forename: Tsunekazu
authors.initials: T
authors.lastname: Hishima
authors.forename: Masanao
authors.initials: M
authors.lastname: Kurata
authors.forename: Goro
authors.initials: G
authors.lastname: Honda
authors.forename: Gunter
authors.initials: G
authors.lastname: Kloppel
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000150:complications / Q000276:immunology* / Q000473:pathology; D000368:Aged; 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; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D010179:Pancreas / Q000276:immunology; D010190:Pancreatic Neoplasms / Q000150:complications / Q000276:immunology* / Q000473:pathology; D010195:Pancreatitis / Q000150:complications / Q000276:immunology* / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology
chemical_list: D007074:Immunoglobulin G
keywords: Autoimmune pancreatitis; IgG4; IgG4-related disease; Intraductal papillary mucinous neoplasm