A 58-year-old woman was referred to our institution for assessment of cardiomegaly seen on chest radiograph (A). A 64-slice multidetector computed tomography angiogram showed a large low-density mass adherent to the inferior wall of the right and left ventricles. The tissue density, measured in Hounsfield units, was –90 to –119, consistent with lipomatous tissue. A cavity surrounded by the mass and filled with contrast communicated to the right ventricle, with a pseudoaneurysmal appearance (B, C, and D; Online Videos 1, 2, and 3). Operative findings revealed a large white-yellow fatty mass adherent to the inferior wall of the right and left ventricles (E). The tumor had infiltrated the right ventricular inferior free wall. Only a thin layer of the myocardium remained, leading to a pseudoaneurysmal appearance. Surgical resection of the tumor and primary closure of the right ventricle were performed. The tumor measured 16 × 13 × 5 cm (F). Histological examination revealed a benign lipoma (G).