Biliary stricture due to mucosal hyperplasia of the common bile duct: a case report.

A 71-year-old man with a tumorous lesion of the common bile duct is presented. Although histological examination of tumor biopsy specimens taken at the time of duodenoscopy or percutaneous transhepatic choledochoscopy showed mucosal hyperplasia, cancer could not be ruled out; therefore, the patient underwent pancreatoduodenectomy. However, histology showed nodular mucosal hyperplasia and an ectopic pancreas adjacent to the papilla of Vater, which was suspected to have contributed to the development of the lesion by stimulating the mucosa of the papilla and the distal common bile duct.