Primary cystic lesions of the liver are very rare. Most of the solid tumours are hepatocellular carcinomas (HCC) with a smaller number being cholangiocarcinomas. The association of HCC with other primary liver malignancies is also extremely rare. This case report is about a 27 year old male patient who presented with a giant cystic lesion of the left liver. A CT scan showed a cystic lesion with internal septations and a thrombus in the main portal vein. The patient underwent an extended left hepatectomy and a portal venotomy with removal of the thrombus. Coexistent hepatocellular and cystadenocarcinoma were reported on histopathological examination. The patient was put on 5-FU postoperatively. He is doing well 11 months after surgery.