BACKGROUND: Hepatobiliary cystadenocarcinoma represents a rare epithelial malignant tumor derived from the intrahepatic bile duct. METHODS: A 71-year-old woman, who had undergone laparoscopic drainage of a cystic lesion of the right hepatic lobe, was misdiagnosed as having hepatic echinococcal disease, and received intracystic infusion of 95% ethanol four years ago. She was admitted to our hospital for further treatment. RESULTS: Physical examination revealed dilated superficial veins across the right abdominal wall. After mapping the direction of blood flow in these vessels, we assumed that this was a sign of inferior vena cava obstruction. Abdominal ultrasound, computed tomography, magnetic resonance imaging combined with magnetic resonance angiography showed a large cystic mass in the right upper quadrant and epigastrium, displacing the adjacent structures, adherent to the inferior vena cava, which was not patent, resulting in dilation of superficial epigastric veins. The patient underwent an exploratory laparotomy. Total excision of the huge mass measuring 16×15 cm was possible under selective vascular exclusion of the liver. Removal of the tumor resulted in immediate restoration of flow in the inferior vena cava. On the basis of the pathology and findings of immunohistochemical analysis, a hepatobiliary cystadenocarcinoma was diagnosed.CONCLUSIONS: In the present case, hepatobiliary cystadenocar-cinoma was accompanied by dilated superficial venous collaterals due to inferior vena cava obstruction. Selective vascular exclusion of the liver allowed a safe oncological resection of the tumor. BACKGROUND: Hepatobiliary cystadenocarcinoma represents a rare epithelial malignant tumor derived from the intrahepatic bile duct. METHODS: A 71-year-old woman, who had undergone laparoscopic drainage of a cystic lesion of the right hepatic lobe, was misdiagnosed as having hepatic echinococcal disease, and was received intracystic infusion of 95% ethanol four years ago. She was admitted to our hospital for further treatment. RESULTS: Physical examination revealed dilated superficial veins across the right abdominal wall. After mapping the direction of blood flow in these vessels, we assumed that this was a sign of inferior vena cava obstruction. Abdominal ultrasound, computed tomography, magnetic resonance imaging combined with magnetic resonance angiography showed a large cystic mass in the right upper quadrant and epigastrium, displacing the adjacent structures, adherent to the inferior vena cava, which was not patent, resulting in dilation of superficial epigastric veins. The patient un derwent an the exploratory laparotomy. Total excision of the huge mass measuring 16 × 15 cm was possible under selective vascular exclusion of the liver. Removal of the tumor resulted in an immediate restoration of flow in the inferior vena cava. On the basis of the pathology and findings of immunohistochemical analysis, a hepatobiliary cystadenocarcinoma was diagnosed. CONCLUSIONS: In the present case, hepatobiliary cystadenocar-cinoma was accompanied by dilated superficial venous collaterals due to inferior vena cava obstruction. Selective vascular exclusion of the liver allowed a safe oncological resection of the tumor.