Clinical features of pancreaticobiliary maljunction: update analysis of 2nd Japan-nationwide survey

Pancreaticobiliary maljunction (PBM) is a congenital anomaly, which can be defined as a union of the pancreatic and biliary ducts located outside off the duodenal wall. We herein investigate clinical features of PBM including as the 2nd report of a Japanese nationwide survey. During a period of 18 years (from 1990 to 2007), 2,561 patients with PBM were registered at 141 medical institutions in Japan. Among them, eligible patients (n = 2,529) were divided into two groups: adult (n = 1,511) and pediatric patients (n = 1,018). Comparisons of clinical features including associated biliary cancers were performed according to the biliary dilatation (BD), age factor, and time era. Only one case in pediatric patients with BD combined with a bile duct cancer (0.1 %). In adult patients, the bile duct cancer and the gallbladder cancer was seen in 6.9 and 13.4 % patients with BD and in 3.1 and 37.4 % patients without BD, respectively. In adult patients with BD, the occurrence rates of biliary cancers were increased in latter period (00'aEuro"07') compared with former period (90'aEuro"99'). The ratio of biliary cancer localization was changed between former and latter period, and the bile duct cancer was increased in latter period (from 5.5 to 9.3 %). The largest series of PBM were evaluated to clarify the clinical features including the associated biliary cancer in this Japan-nationwide survey. This report could be widely used in the future as a reference data for diagnosis and treatment of PBM.