Type 1 Autoimmune Pancreatitis Masquerading as Pancreatic Head Carcinoma.

Obstructive jaundice is a joint clinical presentation with many etiologies, including pancreatic cancer and autoimmune pancreatitis (AIP). Differentiating between these two conditions is pivotal due to the divergent management approaches and prognoses. In this case report, we present a case of a 49-year-old female patient who presented with weight loss, intermittent chronic abdominal pain, and jaundice. She was initially suspected of having pancreatic cancer because of clinical presentation and imaging findings. However, she was ultimately diagnosed with Type 1 AIP due to histopathology findings and elevated immunoglobulin G4. This case highlights the complexities in diagnosis, the role of advanced imaging techniques and tissue sampling, and the lessons learned regarding managing this challenging clinical scenario.