Unclassifiable Congenital Biliary Dilatation With a Meandering Main Pancreatic Duct and Suspected Pancreaticobiliary Maljunction.

Congenital biliary dilatation (CBD) is a congenital disorder in which the bile ducts are locally or diffusely dilated and is specifically defined as a disorder associated with pancreaticobiliary maljunction (PBM). PBM is a congenital anomaly in which the pancreatic and bile ducts merge anatomically outside the duodenal wall. Meandering main pancreatic duct (MMPD) is an anomaly in the shape of the main pancreatic duct (ventral pancreatic duct) in the pancreatic head region that forms an inverted Z-shape or loop shape. Herein, we present the case of a 30-year-old man who experienced intermittent right upper abdominal pain with an unclassifiable type of CBD, MMPD, suspected PBM, and chronic cholecystitis. Although the patient presented uncommon conditions, we analyzed the pathophysiology and speculated the cause of the symptoms. After laparoscopic cholecystectomy, the patient's symptoms were relieved. This is the first case report of the rare coexistence of an unclassifiable CBD, MMPD, and suspected PBM.