[The clinical analysis of autoimmune pancreatitis: a report of 21 cases]

To investigate the clinical feature, diagnostic and therapeutic experience of autoimmune pancreatitis (AIP).

Twenty-one patients with AIP treated in the First Affiliated Hospital, Harbin Medical University from January 2006 to July 2014 were analyzed retrospectively. There were 15 men and 6 women among the 21 cases and the age ranged from 36 to 64 years. The characters of diagnosis and treatment of AIP were explored through clinical symptoms, imaging features, serologic test results, diagnostic treatment, and histopathologic characteristics.

All the patients showed obstructive jaundice and upper abdominal pain to different extents as major manifestations and the levels of serum IgG4, CA19-9, CEA were elevated in 16 cases (76.2%), 6 cases (28.5%) and 3 cases (14.2%), respectively. CT showed diffuse enlargement of the pancreas in 9 cases, localized pancreatic head enlargement in 3 cases and focally pancreatic mass in 9 cases. AIP was confirmed by extrapancreatic involvement, radiological and serological results plus biopsy in 11 cases (52.4%), interpretation of response to steroid in 3 cases (14.3%) and open laparotomy in 7 cases (33.3%). Surgery included choledochojejunostomy in 3 cases, cholecystojejunostomy in 1 case, pancreaticoduodenectomy in 2 cases and distal pancreatectomy combined with splenectomy in 1 case. The pathologic results displayed massive lymphocytes and plasma cells infiltration in the pancreatic tissues as well as parenchymal fibrosis. Except for 1 patient who had no symptom, the regular steroid therapy was performed (oral prednisone) and all the patients were cured. The follow-up time range was from 3 to 93 months, 4 cases (19.0%) were recurrent followed by the symptoms alleviated after the steroid was applied again.

AIP is rare and characterized by non-specific clinical manifestations so that the early diagnosis is difficult with a high misdiagnosis rate. The clinicians should strengthen the recognition of AIP and the definite diagnosis depends on the combination of clinical manifestations, radiological, serological and histopathological results so as to avoid the unnecessary operation.