OBJECTIVETo investigate the characteristic findings of autoimmune pancreatitis (AIP) to increase the recognition of AIP.

METHODSFrom February 2002 to April 2008, a total of 14 cases of AIP were reviewed by clinical, imaging, serologic, histopathologic features and treatment response. There were 13 male and 1 female, with a mean age of 53 years. The main clinical manifestations included progressive obstructive jaundice in 11 cases, upper abdomen pain in 3 cases.

RESULTSDiffuse enlargement of pancreas and diffuse narrowing of the main pancreatic duct (MPD) were observed in 11 cases, while 3 patients showed localized pancreatic head enlargement and focal narrowing of the MPD. Distal common bile duct stenosis was found in all cases. Increased expression of serum immunoglobulin G was found in 7 patients. Autoantibody test was positive in 5 of 12 patients. Nine of 14 patients with AIP had extrapancreatic organ involvement. Massive lymphocytes and plasma cells infiltration in pancreatic tissues were showed on pathology, as well as parenchymal fibrosis. Seven earlier patients were treated initially with surgical laparotomy or resection for suspected malignancy. Steroid therapy was given to the other patients and was responsive. There were 4 recurrences after initial treatment.

CONCLUSIONAIP should be a differential diagnosis in pancreatic head mass in order to avoid unnecessary resection.