[Autoimmune pancreatitis--a rare and difficult differential diagnosis to pancreatic cancer].

BACKGROUND: Autoimmune pancreatitis (AIP) is a rare disorder. Typical clinical symptoms include extrahepatic cholestasis, abdominal pain, and weight loss.

CASE REPORT: The case of a patient with cholestatic icterus and double duct sign is reported, who underwent surgery (Whipple operation) because of suspected pancreatic cancer. Histology of the resected pancreas head revealed AIP. Due to this diagnosis, measurement of IgG4 showed a significantly elevated serum level. Postoperatively, cholestasis parameters remained elevated, which was interpreted as associated sclerosing cholangitis. Therapy with corticosteroids led to normalization of the cholestasis within 4 weeks.

CONCLUSION: AIP should be taken into account as differential diagnosis to pancreatic cancer, especially in cases without clear demarcation of a pancreatic tumor. Measurement of IgG4 may be an important parameter to avoid unnecessary surgery.