48: Primary Cardiac Tumors

Epidemiology

• Primary cardiac tumors are rare with an overall incidence of 0.02 percent. Malignant tumors metastatic to the heart are much more common with an incidence of 1.23 percent. About 25 percent of primary cardiac tumors are malignant (made up mainly of sarcomas), and about 75 percent are benign. Myxomas make up about 50 percent of benign cardiac tumors.

Pathophysiology

• Cardiac tumors arise from various cells in the heart. Clinical effects of these tumors are based chiefly on the size and location of the mass. Tumors can cause obstruction of valvular orifices as well as incompetence of valve leaflets, leading to symptoms of obstruction and congestive heart failure. In addition, friable tumors can embolize, causing systemic effects.

Clinical features

• The most common presentation of cardiac tumors is evidence of congestive heart failure due to obstruction and/or valvular insufficiency. Signs and symptoms of embolization include myocardial infarction, stroke, peripheral malperfusion, and mesenteric ischemia. Constitutional symptoms such as malaise, weight loss, myalgias, and fevers can occur due to elaboration of cytokines. Other presenting signs and symptoms can include arrhythmias, sudden death, chest pain, and pericardial tamponade.

Diagnosis

• A chest x-ray and electrocardiogram can suggest large tumors or those causing conduction disturbances. The mainstay of diagnosis, however, is echocardiography. Transthoracic echocardiography is an excellent screening tool, but transesophageal echocardiograaphy can provide higher resolution and more information about the dynamic effects of the mass during the cardiac cycle and the precise location of the tumor. Computed tomography (CT) scan and magnetic resonance imaging (MRI) are also useful in further characterizing cardiac masses and determining the depth of invasion in cases of malignant lesions.

Treatment

• The mainstay of treatment for the vast majority of cardiac tumors is surgical excision. Resection should be performed as quickly as possible after diagnosis given the risk of systemic embolization. Sarcomas portend a poor prognosis, but survival can be improved with surgical resection when technically feasible. In addition, some studies have suggested that chemotherapy and radiation therapy may enhance survival. Treatment of primary cardiac lymphomas is centered on chemotherapy with surgery only used for palliative debulking.

Outcomes and prognosis

• The prognosis of resectable benign tumors is usually very good with low recurrence rates depending on the type of tumor. In contrast, the prognosis of malignant lesions is dismal with the median survival being only 6 to 18 months, even with surgical resection or transplant.