Low grade myxofibrosarcoma in the right ventricle presenting as pulmonary thromboembolism.

We report an unusual malignant cardiac neoplasm that initially presented as pulmonary thromboembolism in a 78-year-old male. Despite anticoagulation, the pulmonary artery lesion progressed and a mass-like lesion developed in the right ventricular outflow tract. Venoarterial extracorporeal membrane oxygenation was applied before surgery due to the presence of severe right-side heart failure with pulmonary hypertension. A round mass was found in the right ventricle and separate lobulated masses were found in both pulmonary arteries, and these were consistent with low-grade myxofibrosarcoma.