David Aguilar, MD and Glenn N. Levine, MD, FACC, FAHA

1. Which are more common, primary cardiac tumors or metastatic tumors to the heart?

    Metastatic tumors to the heart are markedly more common than primary cardiac tumors, with one source reporting metastatic involvement of the heart to be 20 to 40 times more prevalent than primary cardiac tumors. Primary cardiac tumors are extremely rare, occurring in one autopsy series in less than 0.1% of subjects.

2. What are the most common tumors that metastasize to the heart?

    The most common tumors that spread to the heart are lung (bronchogenic) cancer, breast cancer, melanoma, thyroid cancer, esophageal cancer, lymphoma, and leukemia. Malignant melanoma has the greatest propensity to spread to the heart, with 50% to 65% of patients with malignant melanoma having cardiac metastases. Tumors may spread to the heart via direct extension, the circulatory system, or via lymphatics. Renal cell carcinoma may extend up the inferior vena cava all the way into the heart.

3. What are the most common primary cardiac tumors?

    Benign tumors are more common than malignant tumors, occurring approximately three times as often as malignant tumors. In children, 90% of primary cardiac tumors are benign. The most common benign cardiac tumors in adults are myxomas, accounting for approximately half of all primary cardiac neoplasms; other common benign cardiac tumors are lipomas and papillary fibroelastomas. Rhabdomyomas are the most common benign tumor occurring in infants and children. Interestingly, rhabdomyomas usually regress over time and do not require specific treatment in asymptomatic individuals. Primary and secondary (metastatic) tumors involving the heart are listed in Table 48-1.

4. In what chamber do most myxomas occur?

    Approximately 75% to 80% of myxomas occur in the left atrium (Fig. 48-1), with 15% to 20% occurring in the right atrium. Only 3% to 4% of myxomas arise in the left ventricle and 3% to 4% arise in the right ventricle. Myxomas are usually pedunculated and typically arise from the interatrial septum via a stalk. They are described on gross pathological examination as gelatinous in consistency. They most commonly occur between the third and sixth decades of life, and more frequently occur in women. They can cause effective obstruction of filling of the left or right ventricles, leading to left or right heart failure symptoms and findings, mimicking the symptoms and findings of mitral or tricuspid valve stenosis. Systemic embolism occurs in 30% to 40% of patients. Constitutional symptoms and findings (see Question 6) are also common. Most myxomas occur sporadically, but approximately 7% to 10% may be familial (see Question 10).