title: Reactive fibroinflammatory pseudotumor of the pancreas: report of three cases.
abstract: Reactive fibroinflammatory pseudotumor located in the pancreas is a rare condition. However, we experienced three cases of reactive fibroinflammatory pseudotumor of the pancreas over the previous 2 years. Immunohistochemical staining of immunoglobulin G4 (IgG4) confirmed that Cases 1 and 3 involved IgG4-related disease and that Case 2 did not. In Cases 1 and 3, the masses were formed through autoimmune reaction and were diagnosed as autoimmune pancreatitis (AIP). In Case 2, because only a few IgG4-positive cells were found, it was difficult to diagnose AIP or IgG4-related disease. Reactive fibroinflammatory pseudotumors can develop without the involvement of any autoimmune mechanisms. There seems to be partial overlap between reactive fibroinflammatory pseudotumors and AIP.
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Hirata
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.|Department of Gastroenterological Surgery, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hashimoto
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan. mhirota@krmc.or.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hirota
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.|Department of Gastroenterological Surgery, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Sakata
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.|Department of Gastroenterological Surgery, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kuroki
authors.affiliation: Departments of Pathology and Experimental Medicine, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Ishikawa
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.
authors.forename: Tetsumasa
authors.initials: T
authors.lastname: Arita
authors.affiliation: Department of Surgery, Kumamoto Regional Medical Center, 5-16-10 Honjo, Kumamoto, 860-0811, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yagi
keywords: Autoimmune pancreatitis; IgG4-related disease; Pancreatic cyst; Pancreatic tumor; Reactive fibroinflammatory pseudotumor