A novel variant of pancreaticobiliary maljunction: Complete opening of the common bile duct into the duct of Santorini in a patient with pancreas divisum.

Pancreaticobiliary maljunction (PBM) is a rare congenital anomaly in which the pancreatic and bile ducts unite outside the duodenal wall, forming an abnormally long common channel that permits reciprocal reflux of pancreatic juice and bile. This leads to a high risk of recurrent pancreatitis, cholangitis, biliary stone formation, and biliary tract malignancy. Type D PBM, particularly when associated with complete pancreas divisum and aberrant bile duct drainage, represents an exceptionally rare and complex variant. We report the case of a 20-year-old female with a long-standing history of recurrent cholestasis and acute pancreatitis who presented with fever, jaundice, and abdominal pain accompanied by laboratory findings consistent with cholangitis and pancreatitis. Cross-sectional imaging and magnetic resonance cholangiopancreatography demonstrated type D PBM, complete pancreas divisum, and anomalous drainage of the common bile duct into the duct of Santorini with intraductal sludge. Emergency endoscopic retrograde cholangiopancreatography confirmed the diagnosis, and endoscopic sphincterotomy with biliary stenting led to clinical improvement. Given the persistent risk of malignancy and refractory clinical course, extrahepatic bile duct resection with Roux-en-Y hepaticojejunostomy was performed. Despite initial improvement, intermittent episodes of acute pancreatitis persisted, ultimately necessitating a pylorus-preserving pancreaticoduodenectomy. Histopathological examination revealed chronic inflammatory changes without dysplasia or malignancy. The patient recovered uneventfully and remains asymptomatic. This rare case illustrates the complexity of type D PBM associated with complete pancreas divisum and highlights the importance of early anatomical recognition and a stepwise, individualized treatment strategy. In patients with refractory symptoms and complex ductal anomalies, surgical intervention beyond endoscopic management may be required to prevent recurrent disease and reduce the risk of malignant transformation.