of hepatocellular carcinoma (HCC). Transesophageal echocardiography from both midesophageal bicaval view (Fig. 1, Panel E, Supplementary Video S2) and four-chamber view (Fig. 1, Panel F) highlighted the highly mobile mass that occupied the right chambers and extended into the PA and therefore, blocked both the RV inflow and outflow tract. However, few hours after admission and despite the attempted rescue thrombolysis, the patient experienced sudden cardiac arrest. HCC patients are known to have an increased risk of thrombosis; however, a giant metastatic thrombus that extends from the IVC to the PA is still considered an unusual presentation of HCC. Informed consent: The informed consent was obtained from the patient. Supplementary Video S1. Transthoracic echocardiography, subcostal view: giant mass occupying the right atrium (RA), protruding into the right ventricle (RV), and significantly obliterating the tricuspid valve. Supplementary Video S2. Transesophageal echocardiography, midesophageal bicaval view revealing highly mobile mass occupying the right chambers.