Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide [
1]. It has a high mortality rate, with most patients succumbing to the disease within one year [
1]. The presence of metastatic disease in these patients markedly reduces survival [
2]. Recently, the occurrence of liver cancer in the United States of America has been increasing because of the increased frequency of hepatitis C [
3]. Liver cancer tends to spread to nearby lymph nodes, bones and lungs. In rare cases, it spreads to the chest wall with or without identified primary liver cancer. It is essential to diagnose HCC in its early stages to ensure patient survival [
2,
4]. Ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) are the primary imaging methods for the diagnosis of liver cancer [
5]. The PET scan is an emerging imaging modality that measures and distinguishes the increased rates of glucose metabolism and oxygen consumption in tumor tissue from normal surrounding tissue. The advantage of PET scans is that they measure metabolic changes at the cellular level [
6]. On the other hand, cross-sectional imaging modalities such as CT, ultrasound, and MRI detect anatomical changes. Thus, PET scans allow complementary anatomical detection and measurement of cellular activity in tumors. However, the average false-negative rate of PET scans is 40% to 50% for the detection of HCC because of active glucose metabolism in normal hepatic parenchyma. It has been demonstrated that glycolysis metabolism within HCC is equivalent to or less than that of normal liver tissue. Therefore, most primary HCCs are underdetected by PET scans [
7,
8]. However, PET scans have shown benefit in the detection of early metastasis in extrahepatic sites, especially in the frequent metastatic organs, such as the colon, lung, brain and lymph nodes [
9,
10]. In this case report, we describe a chest wall metastasis of HCC that was uniquely detected by PET scan but not by CT scan. This report indicates that whole-body PET is a potentially valuable method to screen for the early presentation of extrahepatic metastatic disease.