Atrial Myxoma

General Information
  • Most common primary cardiac neoplasm
  • Prevalence of cardiac tumors at autopsy ranges from 0.001% to 0.3%
  • Thought to originate from entrapped entrapped embryonic foregut
  • Histologically, composed of scattered cells within a mucopolysaccharide stroma
  • Produce VEGF, which contributes to the induction of angiogenesis and the early stages of tumor growth
  • On a macroscopic level, typical myxomas are pedunculated and gelatinous in consistency; the surface may be smooth, villous, or friable.
  • 35 percent of myxomas are friable or villous, and these tend to present with emboli.
Clinical Manifestations
  • Symptoms:
    • Due to obstruction of blood flow, valvular regurgitation, impaired contractility
    • Can see dyspnea, orthopnea, paroxysmal nocturnal dyspnea, pulmonary edema, cough, hemoptysis, edema, and fatigue
    • Direct invasion of myocardium can cause arrhythmias, heart block, or pericardial effusion with or without tamponade
    • Left atrial tumors may release tumor fragments or thrombi into the systemic circulation, leading to embolization in multiple vascular territories
    • May be worse in certain body positions, due to motion of the tumor within the atrium
  • Signs:
    • On physical examination, a characteristic “tumor plop” may be heard early in diastole.
    • Constitutional symptoms (e.g., fever, weight loss) are seen in around 30 percent of patients.
    • Laboratory abnormalities (e.g., anemia and elevations in the ESR or CRP) are present in 35 percent, usually those with systemic symptoms].

 

Diagnostic Evaluation 
  • Echocardiography
    • Images both the myocardium and the cardiac chambers can usually identify the presence of a mass
    • In addition, echocardiography may provide information about any obstruction to the circulation, as well as the likelihood that the tumor could be a source of emboli
    • TTE is sufficient, but TEE may be better. The superior diagnostic utility of TEE is due to the proximity of the esophagus to the heart, the lack of intervening lung and bone, and the ability to use high-frequency imaging transducers that afford superior spatial resolution.
  • Cardiac MRI and Computerized Tomography
    • MRI is preferred. In addition to furnishing detailed anatomic images, the T1- and T2-weighted sequences reflect the chemical microenvironment within a tumor, thereby offering clues as to the type of tumor that is present.
    • However, CT scanning is still useful when MRI is not immediately available or is contraindicated.
  • PET scan
    • Useful in identifying cardiac involvement in patients with metastatic tumors, atrial myxoma or lipomatous septal hypertrophy.
  • Transvenous biopsy
    • Limited data is available on the risks and benefits of transvenous biopsy of suspected cardiac tumors.
    • Because myxomas may embolize, transvenous biopsy is not generally warranted if the appearance is typical on noninvasive imaging.
    • Biopsy is considered reasonable for other cardiac tumors if potential benefits are deemed sufficient to outweigh potential risks.

 

Treatment and Prognosis

 

  • Once a presumptive diagnosis of myxoma has been made on imaging studies, prompt resection is required because of the risk of embolization or cardiovascular complications, including sudden death.
  • The results of surgical resection are generally very good, with most series reporting an operative mortality rate under 5 percent.
  • Postoperative recovery is generally rapid.
  • Atrial arrhythmias or atrioventricular conduction abnormalities were present postoperatively in about 25% of patients
  • Approximately 5% risk for recurrence, suggesting the need for careful follow-up

Adapted from: Cohen et al. Atrial Myxoma: A Case Presentation and Review.Cardiology Research. 3 (1), 2012, 41-44. CC BY-SA 4.0