Myxoma, the most common type of primary cardiac tumor, accounts for 30% to 50% of all primary tumors of the heart. It has an annual incidence of 0.5 per million population and most commonly presents in adults 30 to 50 years of age, although it can occur in nearly all age groups ranging from 1 to 83 years. Sixty-five percent of cardiac myxomas occur in women, and 4.5% to 10% of cardiac myxomas are familial; thus, routine screening of first-degree relatives of myxoma patients is recommended. Although there was debate in the past about whether cardiac myxoma was, indeed, a neoplastic entity or an organized thrombus, recent gene expression and immunohistochemical studies have shown that cardiac myxoma is a neoplasm with tumor cells arising most likely from multipotent mesenchymal cells. Other features suggestive of its being a neoplastic process include its ability to recur, occurrence in multiple sites, and occurrence in families. Despite several documented reports of metastases to various anatomic sites, the typical cardiac myxoma is regarded as a benign neoplasm in a conventional sense, and the reported metastases most likely represent tumor growth from embolic tumor fragments that are deposited along the arterial circulation in different remote sites. Thus, although histopathologically benign, cardiac myxomas can cause chronic systemic inflammation, embolism, or intracardiac obstructions, leading to increased morbidity.
Cardiac myxoma is the most common primary cardiac tumor to produce tumor emboli, and it has been reported to embolize to virtually any organ or tissue. Constitutional and nonembolic systemic findings secondary to cardiac myxoma include several nonspecific symptoms, such as fever, weight loss, fatigue, myalgia, arthralgia, muscle weakness, and Raynaud syndrome. These nonspecific symptoms often create the most confusion and difficulty in the diagnosis because they may mimic immunologic diseases. They are believed to be related to IL-6 release by the myxoma tumor cells.
Cardiac myxoma most commonly occurs in the left atrium. A recent meta-analysis showed that 83% of cardiac myxomas occur in the left atrium, 12.7% occur in the right atrium, and 1.3% are biatrial.Occurrence in the ventricles is uncommon; only 1.7% and 0.6% of myxomas occur in the left ventricle and the right ventricle, respectively.
The treatment of symptomatic cardiac myxoma is prompt surgical resection of the tumor with the patient placed on cardiopulmonary bypass. Complete excision is the goal, although this may not be possible in all instances. Immediate postoperative mortality in most series ranges from 0% to 7.5%. Other common postoperative complications include arrhythmias, which may require long-term medication. Recurrence develops in about 3% of tumors, although the rate is higher with familial cardiac myxomas and can occur anywhere from 3 months up to 14 years postoperatively. Recurrences can be local or in extracardiac locations, such as the brain, lung, skeletal muscle, bone, kidney, gastrointestinal tract, skin, and other soft tissue sites.
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