Abstract
A 73-year-old man who had received endoscopic sphincterotomy (EST) for a common bile duct stone and acute cholangitis three years before, was admitted for investigation of right upper quadrant abdominal pain and fever. Computed tomography (CT), magnetic resonance cholangiopancreatography and ultrasonography showed an elongated common bile duct stone with mild dilatation of the bile duct. Furthermore, CT revealed that the common bile duct stone contained a needle-shaped material, presenting a characteristic bright dot corresponding to the density of bone. Under a diagnosis of a common bile duct stone containing a nidus of fish bone, EST was performed. A friable and elongated stone containing needle-shaped material was removed from the common bile duct. The component analysis of the needle-shaped material showed mainly calcium and phosphorus, suggesting that the needle-shaped material seemed to be a fish bone. An unusually elongated shaped stone of the common bile duct, which contains a bright dot of bone density on CT, should be considered as common bile duct stone containing a nidus of fish bone.
