Gallbladder agenesis with a stone in the cystic duct bud.

An 84-year-old woman was admitted to the hospital because of pyloric stenosis caused by gastric cancer. Abdominal computed tomography and magnetic resonance imaging failed to demonstrate the gallbladder, but showed a gallstone in a duct-like structure parallel to the common bile duct. When laparotomy was performed, the gallbladder and the fossa were not observed, and a blind-end duct, similar to a cystic duct, was found beside the common bile duct.