Various FDG Avidity of Synchronous Second Primary Hepatocellular Carcinomas in a Patient with Breast Cancer

We report a case of second primary hepatocellular carcinoma (HCC) with various fluorodeoxyglucose (FDG) avidity on cell-differentiation. A 62-year-old woman with history of breast cancer had two liver nodules on follow-up CT scan. FDG PET/CT showed a nodule with the maximal standardized uptake value of 6.8 in left hepatic lobe and the other one with background activity in right live. The pathology revealed both nodules as HCC, moderate-differentiation in the FDG-devoid one and poor-differentiation in the FDG-avid one, respectively. These second primary HCCs mimic metastatic lesions of breast cancer and present various FDG avidity by different differentiation on PET/CT.