Recognition of a Sausage-Shaped Pancreas on Non-contrast Computed Tomography as an Early Clue to Type 2 Autoimmune Pancreatitis in a Young Adult

Autoimmune pancreatitis (AIP) is an uncommon form of chronic pancreatitis characterized by immune-mediated inflammation and a dramatic response to corticosteroid therapy. Two distinct subtypes are recognized, each with differing clinical, serological, and histopathologic profiles. Type 2 AIP predominantly affects younger patients and is not associated with elevated serum immunoglobulin G4 levels, making the diagnosis particularly challenging. We report a 28‑year‑old man who presented with recurrent epigastric pain and elevated serum lipase. Non‑contrast computed tomography (CT) revealed no peripancreatic fat stranding or fluid collection; however, subtle loss of the normal pancreatic lobular architecture produced a sausage‑shaped configuration of the pancreas. Further evaluation with magnetic resonance cholangiopancreatography demonstrated diffuse irregular narrowing of the main pancreatic duct. Endoscopic ultrasound‑guided biopsy confirmed idiopathic duct‑centric pancreatitis with granulocytic epithelial lesions, consistent with type 2 AIP. Complete clinical, biochemical, and radiologic resolution was achieved following corticosteroid therapy. This case highlights that a sausage‑shaped pancreas on non‑contrast CT, even in the absence of typical inflammatory features, should prompt consideration of AIP in young adults.