Chapter 30

• An uncommon but important differential diagnosis of cardiac masses.
• Diagnosis is suspected by history, physical examination, and imaging characteristics and confirmed by biopsy of mass.

Cardiac tumors arise either as a primary tumor of the heart or more commonly from metastasis of a distant noncardiac primary tumor. Because of the low incidence and nonspecific clinical manifestations, cardiac tumors have often been diagnosed incidentally during evaluation of a seemingly unrelated problem or misdiagnosed as other cardiac conditions. A high index of suspicion in combination with characteristic cardiovascular imaging study are essential for rapid identification of cardiac tumors.

### Metastatic Cardiac Tumors

Metastatic cardiac tumors are about 40 times more common than primary tumors. Cardiac metastases occur in approximately 5% of patients who die of malignant tumors and are often present as pericardial effusions; myocardial, coronary, and intracavitary involvement occurs with less frequency. The tumor that most often metastasizes to the heart is disseminated malignant melanoma, which occurs in 50–65% of afflicted patients. Other tumors with high predilection for cardiac metastasis are bronchogenic carcinoma, breast cancer, renal cell carcinoma, mesothelioma (by direct extension or hematogenous spread), and lymphoma and leukemia (by lymphatic spread). Rarely, adenocarcinoma of the colon can metastasize to the heart by lymphatic or hematogenous spread, usually affecting first the pericardium and then the myocardium. Cardiac metastases that occur in patients with colon cancer are usually preceded by involvement of other organs. Metastases to the endocardium have been reported in renal cell carcinoma, adenocarcinoma of the stomach, laryngeal carcinoma, pancreatic cancer, and mucinous adenocarcinoma of the cecum and of the ovary. Renal cell carcinomas can extend into the inferior vena cava, and the tumor thrombus occasionally involves the right atrium (Figure 30–1).

###### Figure 30–1.

Transthoracic echocardiogram in a 65-year-old man with a history of renal cell carcinoma in whom dyspnea and lower extremity edema developed. A: The apical four-chamber view shows a large mass most likely representing metastatic renal cell carcinoma in the right atrium. B: During diastole, the tumor prolapses through the tricuspid valve. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

### Primary Tumors

Primary tumors of the heart are rare, with an incidence from 0.001% to 0.28% reported in unselected autopsy studies. Although myxoma is the most frequent tumor type in adults, rhabdomyomas represent the most common type in the pediatric population.

#### Benign

The majority (75–80%) of primary cardiac tumors are benign and therefore potentially curable (Table 30–1).

Table 30–1. Primary Cardiac Neoplasms.

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