[An analysis of clinical characteristics of autoimmune pancreatitis]

To increase the appreciation of manifestations in autoimmune pancreatitis (AIP) and to decrease misdiagnosis rate by investigating the clinical characteristics of AIP.

Clinical data were collected and laboratory, imaging and histopathology were analyzed from the Chinese PLA General Hospital from 1995 to 2009. Patients with AIP were included in the study.

Eight patients (male 6, female 2) aged 35 - 69 (52.4 ± 9.4) years were diagnosed as AIP from 2006 to 2009. The main clinical manifestations include intermittent jaundice in 6 cases (6/8), abdominal pain in 5 cases (5/8), weight loss in 4 cases (4/8), and accompanied with other diseases of immune system in 4 cases (4/8). The imaging showed head of pancreas enlargement in 3 cases (3/8) and whole pancreas enlargement in 5 cases (5/8). There is a "banana-peel like" ring around the pancreas and irregular stenosis of pancreatic duct. Massive lymphocytes and plasma cells infiltration and parenchymal fibrosis were shown in pancreatic tissues, bile duct, salivary gland and liver in pathology. Clinical manifestations, laboratory examinations and images in 7 cases (7/8) were improved after treatment with prednisone. Twenty-two of them were misdiagnosed as pancreatic or biliary carcinoma and 21 were performed laparotomy in the period of 1995 - 2005 (23 cases). After 2006, however, the misdiagnosis rate significantly decreased from 95.7% (22/23) to 0.

AIP seems to be a systemic autoimmune disease rather than an isolated disorder, markedly overlapping with other autoimmune diseases. Definitive diagnosis can be improved by the detection of immune parameters and pathological examination.