A case report of a common bile duct stone formed from a fish bone

A 79-year-old woman was admitted for investigation of epigastric pain and jaundice. Abdominal computed tomography showed a common bile duct stone with a needle-like calcification. Endoscopic sphincterotomy was performed, and the stone was extracted from the common bile duct. After endoscopic sphincterotomy, laparoscopic cholecystectomy was performed. Pathological findings and component analysis of the stone suggested that it was formed from a fish bone. We report a rare case of a common bile duct stone formed from a fish bone.