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).

5. What are the most common primary malignant tumors?

    The most common primary malignant tumors are sarcomas (Figs. 48-2 and 48-3). Such sarcomas include angiosarcomas (the most common), rhabdomyosarcomas, fibrosarcomas, and leiomyosarcomas. Upon imaging, sarcomas often appear as large heterogeneous, infiltrative masses that frequently occupy most of the affected chamber (see Fig. 48-3). The results of surgery or chemotherapy in the treatment of cardiac sarcomas have been generally poor, with mean survival of only 6 to 12 months.

6. What symptoms do cardiac tumors cause?

    Symptoms of tumors often depend on the size and the location of the tumor, as well the histology of the tumor itself. Left-sided cardiac tumors may manifest with cardioembolic features such as stroke, visceral infarction, or peripheral emboli. Large cardiac tumors may also present with symptoms attributed to obstruction of flow or valvular dysfunction. Left atrial myxomas may cause effective mitral valve stenosis (or regurgitation). Tumors may also cause hemodynamic effects via compression or mass effects. Tumors may lead to atrial or ventricular arrhythmias. Tumors involving the pericardium can cause pericardial effusion and tamponade. Constitutional symptoms (fatigue, weight loss, fever) occur not infrequently, as well as anemia, elevated erythrocyte sedimentation rate, elevated C-reactive protein, and other nonspecific laboratory findings. In patients with known noncardiac cancer, the development of arrhythmias (particularly atrial fibrillation) or development of findings suggesting pericardial effusion or tamponade (distended neck veins, hypotension, paradoxical pulse, new low voltage on the electrocardiogram [ECG]) should prompt immediate evaluation for cardiac or pericardial metastasis.

7. What is the workup for suspected cardiac tumors?

    The initial workup is a transthoracic echocardiogram (echo). Many tumors will also be discovered incidentally or serendipitously by cardiac echo. Tumors may be further evaluated with transesophageal echo (TEE), cardiac magnetic resonance imaging (MRI), or cardiac computed tomography (CT). The role of positron emission tomography (PET) in the evaluation of cardiac tumors is evolving. Transvenous endomyocardial biopsy is generally not warranted for diagnosis but could be considered if the diagnosis cannot be established by noninvasive modalities (such as cardiac MRI) or less invasive (noncardiac) biopsy. Cytological analyses of pericardial effusion or pericardial biopsy may provide diagnostic information regarding metastatic cardiac tumors.

8. What is a “tumor plop”?

    A tumor plop is a sound heard in early diastole during auscultation. It is produced when a left atrial myxoma prolapses into the left ventricle during diastole (Fig. 48-4). The sound may be due to the tumor striking the left ventricular wall or to tension created on the tumor stalk.

9. What is lipomatous hypertrophy of the interatrial septum?

    Lipomatous hypertrophy is an abnormal, exaggerated growth of normal fat cells. It occurs in the interatrial septum, resulting in the appearance of a thickened atrial septum. The finding itself is benign.

10. What is the most common valvular tumor?

    The most common valvular tumor is papillary fibroelastoma. Papillary fibroelastomas are the second most common primary benign cardiac tumors and comprise 75% of valvular tumors. The most usual location is on the mitral and aortic valves, although they can occur on right-sided valves. Papillary fibroelastoma are often small (<1 cm) and appear flower-like or frond-like, with a narrow stalk. Most common symptoms related to papillary fibroelastomas are related to embolic events, such as strokes or transient ischemic attacks.

11. What is the Carney complex?

    Known by various names and acronyms, the Carney complex is an autosomal-dominant syndrome consisting of cardiac myxomas, cutaneous myxomas, spotty pigmentation of the skin, endocrinopathy, and other tumors. Myxomas occurring as part of the Carney complex are reported to account for 7% of all cardiac myxomas. Myxomas occurring as part of the Carney complex often present earlier in life, tend to be located in atypical locations, are often multiple, and often have a higher rate of recurrence after surgical resection compared with sporadic myxomas.

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