title: Autoimmune pancreatitis presenting as a mass in the head of the pancreas: a diagnosis to differentiate from cancer.
abstract: We report a case of autoimmune pancreatitis presenting as a mass in the head of the pancreas that was successfully diagnosed without pancreaticoduodenectomy. The patient was a 64-year-old man who had no complaint. A routine physical checkup unexpectedly revealed mild diabetes and a low-echoic mass in the pancreatic head. The diagnosis was made by noting irregular narrowing of the main pancreatic duct, hypergammaglobulinemia, and increased immunoglobulin G levels. An open wedge biopsy of the mass was performed; this showed a marked fibrosis with lymphocyte- or macrophage-predominant inflammatory infiltrates. Immunohistochemical study revealed that the remnant acinar cells expressed Fas (CD95) ligand and not Fas. We review some of the literature and discuss various features and diagnostic clues of autoimmune pancreatitis. Awareness of this pathologic condition may prevent confusion with pancreatic malignancy and unnecessary surgery.
authors.affiliation: Department of Surgery, Kanbara Municipal Hospital, Ihara-Gun, Shizuoka, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tabata
authors.forename: Joji
authors.initials: J
authors.lastname: Kitayama
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kanemoto
authors.forename: Tomoki
authors.initials: T
authors.lastname: Fukasawa
authors.forename: Hideki
authors.initials: H
authors.lastname: Goto
authors.forename: Koichi
authors.initials: K
authors.lastname: Taniwaka
mesh_terms: D001327:Autoimmune Diseases / Q000175:diagnosis*; D001706:Biopsy; D002908:Chronic Disease; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D010195:Pancreatitis / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology