Hepatic cystadenocarcinoma (HC) is an exceptional epithelial tumour that probably arises from a previously benign cystadenoma. Cystadenoma and cystadenocarcinoma of the liver account for 5% of intrahepatic cystic masses of biliary origin. We report a case of HC located in the left lobe of the liver and treated by left lateral sectionectomy after radiofrequency (RF) coagulation of the liver parenchyma. The postoperative course was uneventful and the patient recovered rapidly. Histological analysis revealed a mucinous cystadenocarcinoma. Preoperative assessment of malignancy in cystic lesions of the liver is a difficult challenge. Complete excision of HC is the only chance for cure. Liver resection after radiofrequency coagulation seems safe and blood loss is minimal.