Hepatobiliary cystadenocarcinomas (BCACs) with mesenchymal stroma are a rare cystic lesion. This tumour needs to be distinguished from benign biliary cystadenoma, which is antecedent in most cases. The treatment of choice is radical excision of the mass. The diagnostic evaluation, surgical management, pathological characteristics, treatment and follow-up of one patient with hepatobiliary cystadenocarcinoma with ovarian stroma is described. Preoperative diagnosis of BCACs is often difficult, because their clinical manifestations are similar to those of other hepatic cystic lesions. MRI is suitable for accurate characterisation of cystic biliary lesions, but distinguishing between cystadenoma and cystadenocarcinoma remains difficult on the basis of imaging findings. Complete surgical excision gives a relatively good chance of long-term survival because of the slow growth rate of these tumours.