RESUMO
BACKGROUND: Douglas described choledochal cysts in 1852 and Todani proposed an anatomy-based classification in 1977. The classification is the most extensively used, but does not include some rare variations. We present a case of hepatic duct diverticulum, one of the variations, and discuss its diagnosis and treatment. METHODS: A 57-year-old woman presented with upper abdominal pain and discomfort associated with nausea and vomiting. She was finally diagnosed with cholelithiasis and right hepatic duct diverticulum. RESULT: The patient underwent resection of the hepatic duct diverticulum and cholecystectomy, and was asymptomatic 26 months after surgery. CONCLUSIONS: Hepatic duct diverticulum is a rare form of choledochal cyst, not included in Todani's classification. Todani's classification including this and other uncommon variations of choledochal cysts must be reviewed. The best diagnostic imaging methods and treatment for choledochal cysts must be defined.