Pancreatobiliary Maljunction-associated Gallbladder Cancer Is as Common in the West, Shows Distinct Clinicopathologic Characteristics and Offers an Invaluable Model for Anatomy-induced Reflux-associated Physio-chemical Carcinogenesis

OBJECTIVE To determine the associations of pancreatobiliary maljunction (PBM) in the West. BACKGROUND PBM (anomalous union of common bile duct and pancreatic duct) is mostly regarded as an Asian-only disorder, with 200X risk of gallbladder cancer (GBC), attributed to reflux of pancreatic enzymes. METHODS Radiologic images of 840 patients in the U.S. who underwent pancreatobiliary resections were reviewed for PBM and contrasted with 171 GBC cases from Japan. RESULTS Eight % of the US GBCs (24/300) had PBM (similar to Japan; 15/171, 8.8%), in addition to 1/42 bile duct carcinomas and 5/33 choledochal cysts. None of the 30 PBM cases from the US had been diagnosed as PBM in the original work-up. PBM was not found in other pancreatobiliary disorders. Clinicopathologic features of the 39 PBM-associated GBCs (US:24, Japan:15) were similar; however, comparison with non-PBM GBCs revealed that they occurred predominantly in females (F/M = 3); at younger (