Autoimmune pancreatitis presenting as obstructive jaundice – A diagnostic challenge

Abstract

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis which can mimic carcinoma head of the pancreas or distal cholangiocarcinoma, causing the diagnostic dilemma. A 64-year-old postmenopausal woman presented with jaundice, generalized itching, and intermittent low-grade fever for 2 weeks. On evaluation, she had a bulky pancreas on imaging and distal biliary stricture on magnetic resonance cholangiopancreatography. She was planned for Whipple's resection, but her serum immunoglobulin G4 (IgG4) was very high. She was started on oral high-dose steroids considering the possibility of AIP and had significant improvement after 2 weeks of treatment. AIP can mimic distal cholangiocarcinoma and can cause a diagnostic challenge in patients admitted with obstructive jaundice. The presence of high serum IgG4 level and treatment response to steroids help in making the diagnosis. This case reminds the readers to consider AIP in patients with obstructive jaundice who have imaging findings of distal cholangiocarcinoma to avoid unnecessary operations on patients without cancer.