Diagnostic Challenges in Autoimmune Pancreatitis: A Case of Progressive Painless Jaundice With an Uncertain Etiology.

Autoimmune pancreatitis (AIP) is a rare cause of pancreatitis compared with more common etiologies such as gallstone or alcohol-related pancreatitis. In this report, we present the case of a 61-year-old man with no significant past medical history who presented with progressive, painless jaundice. His non-specific clinical presentation was compatible with a broad differential diagnosis, initially raising concern for malignant biliary obstruction. Ultimately, endoscopic ultrasound with tissue biopsy was required to establish the diagnosis of AIP, highlighting the diagnostic challenges posed by this uncommon entity.