Giant Pancreatic Duct Calculi in the Common Channel Two Decades Post Choledochojejunostomy: The Synergistic Impact of Persistent Anomalous Pancreaticobiliary Union and an Elongated Blind Stump

Anomalous pancreaticobiliary ductal union (APBDU) represents a congenital anomaly predisposing patients to biliary dilatation. This aberrant architecture facilitates the intermingling of pancreatic and biliary fluids, thereby elevating susceptibility to cholelithiasis and malignancies of the biliary tract. While radical cholangiojejunostomy constitutes the standard therapeutic intervention, it frequently fails to rectify the underlying APBDU. Retention of an excessively elongated common bile duct (CBD) remnant can generate a blind loop, precipitating stone formation within the common channel years following the procedure. Such delayed manifestations in adult populations remain scarcely documented. We herein present a case involving a patient with P-B-type APBDU who exhibited symptoms two decades post-cholangiojejunostomy. Radiological assessment identified a CBD stump measuring approximately 2.5 cm alongside a substantial pancreatic calculus. This instance underscores the compounding effects of uncorrected APBDU morphology and a surgically induced, overly extensive blind loop, extending beyond the conventional paradigm of pancreaticobiliary reflux. Management was achieved exclusively via endoscopic sphincterotomy coupled with accessory cholangioscopy-assisted lithotomy. This report bridges a critical knowledge gap regarding extremely late-onset pancreatic duct stones within the common channel subsequent to cholangiojejunostomy. Furthermore, we underscore the imperative for precise preoperative evaluation of biliary anatomy and stringent intraoperative regulation of stump length.