A 43-year-old male patient presented with a mass lesion on the right liver lobe, segment 5, in radiological imaging and elevated alpha-fetoprotein levels (323 ng/mL) compatible with hepatocellular carcinoma (HCC). Positron emission tomography/computed tomography (PET/CT) images showed background level F-18-FDG uptake in the mass lesion. In addition, a secondary focus of increased F-18-FDG uptake was detected on the left liver lobe, segment 2, approximately 1,5 cm in diameter. Histopathological examination revealed HCC in the larger mass lesion with a lower F-18-FDG uptake, and cholangiocellular carcinoma in the smaller mass lesion with a higher F-18-FDG uptake. To our knowledge, this is the first case report of two histopathologically different primary malignant liver tumors in two distinct segments of the liver detected by PET/CT.