A 71-year-old man with hepatocellular carcinoma (HCC) presented with intracavitary cardiac involvement detected incidentally on surveillance computed tomography. Tumor with associated thrombus was found to extend from the liver through the inferior vena cava into the right atrium. This intracardiac mass prolapsed intermittently into the right ventricle, causing functional tricuspid stenosis. The mass was resected but recurred after 4 months, eventually causing refractory right-sided heart failure. This case illustrates how intracavitary cardiac involvement of HCC can develop insidiously and confer significant hemodynamic compromise. A review of the published research, including postmortem studies, demonstrates that the frequency of intracardiac mass lesions in HCC is not insignificant. In conclusion, early detection and diagnosis may have increasing importance in the advent of new therapies for treating advanced HCC.