Metastatic tumors greatly outnumber primary cardiac tumors. Except for CNS tumors, any malignancy can metastasize to the heart.
Metastatic cardiac tumors are much more frequent than primary tumors. Just as with primary tumors, they can cause disturbances such as valvular malfunction, heart failure, tachyarrhythmias, conduction defects, syncope, or pericardial effusion. They may be unrecognized in the patient with advanced cancer but may contribute to death. Tumors metastasize to the heart via blood or lymphatics. Nearby tumors such as carcinoma of the lung or mediastinal tumors may spread to the heart by extension. Cardiac metastases usually reflect advanced metastatic disease. It is rare that the heart is the only site of metastases. Except for CNS tumors, almost any organ can be the primary site. Melanomas often metastasize to the heart. Other common primary lesions are carcinomas of the breast, lung, or esophagus, and lymphomas. The heart may be infiltrated in cases of leukemia. Renal tumors, Wilms or renal cell carcinoma, can reach the heart by growing into the renal vein, into the inferior vena cava and into the right atrial cavity. There are rare reports of spread of a benign tumor, leiomyoma of the uterus, to the right atrial chamber via intravascular growth in the inferior vena cava.