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'-07') compared with former period (90'-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.