Pancreaticobiliary Maljunction Presenting With Choledocholithiasis: A Case Report

Pancreaticobiliary maljunction, an anatomical variant where the common bile duct and main pancreatic duct merge before entering the duodenum, predisposes to pancreaticobiliary reflux with related complications. We present the case of a 69-year-old woman with abnormal liver function tests and progressive hyperbilirubinemia, with biliary dilatation and choledocholithiasis. Magnetic resonance cholangiopancreatography (MRCP) revealed pancreaticobiliary maljunction with choledocholithiasis. Endoscopic ultrasound (EUS) confirmed the presence of two stones within the anomalous common channel, and same-session endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy, sphincteroplasty, and balloon extraction achieved complete ductal clearance. Follow-up MRCP demonstrated the resolution of the ductal dilatation. This case highlights the diagnostic value of combined MRCP and EUS in delineating pancreaticobiliary maljunction and stone burden, as well as the role of ERCP in the management of lithiasis. Awareness of this variant is essential to optimize procedural planning, reduce complications, and ensure follow-up, due to the increased biliary malignancy risk associated with pancreaticobiliary maljunction.