Cardiac Myxoma

A myxoma is a rare benign tumor of the heart. Myxomas are the most common primary cardiac tumor in adults, and are most commonly found within the left atrium. Myxomas may also develop in the other heart chambers. The tumor is derived from multipotent mesenchymal cells.

Causes

Myxomas are the most common type of adult primary heart tumor. Most myxomas arise sporadically (90%), and only about 10% are thought to arise due to inheritance.

About 10% of myxomas are inherited, as in Carney syndrome. Such tumors are called familial myxomas. They tend to occur in more than one part of the heart at a time, and often cause symptoms at a younger age than other myxomas. Other abnormalities are observed in people with Carney syndrome include skin myxomas, pigmentation, endocrine hyperactivity, schwannomas and epithelioid blue nevi. Myxomas are more common in women than men.

Signs and symptoms

Symptoms may occur at any time, but most often they accompany a change of body position. Pedunculated myxomas can have a "wrecking ball effect", as they lead to stasis and may eventually embolize themselves. Symptoms may include:

• Shortness of breath with activity
• Platypnea – Difficulty breathing in the upright position with relief in the supine position
• Paroxysmal nocturnal dyspnea – Breathing difficulty when asleep
• Dizziness
• Fainting
• Palpitations – Sensation of feeling your heart beat
• Chest pain or tightness
• Sudden Death (In which case the disease is an autopsy finding)

The symptoms and signs of left atrial myxomas often mimic mitral stenosis. General symptoms may also be present, such as:

• Cough
• Pulmonary edema, as blood backs up into the pulmonary artery, after increased pressures in the left atrium and atrial dilation
• Hemoptysis
• Fever
• Cachexia – Involuntary weight loss
• General discomfort (malaise)
• Joint pain
• Blue discoloration of the skin, especially the fingers change color upon pressure, cold, or stress (Raynaud's phenomenon)
• Clubbing – Curvature of nails accompanied with soft tissue enlargement of the fingers
• Swelling – any part of the body
• Presystolic heart murmur

These general symptoms may also mimic those of infective endocarditis.

Complications

• Arrhythmias
• Pulmonary edema
• Peripheral emboli
• Spread (metastasis) of the tumor
• Blockage of the mitral heart valve
• Stroke
• Fusiform cerebral aneurysms

Diagnosis

A doctor will listen to the heart with stethoscope. A "tumor plop" (a sound related to movement of the tumor), abnormal heart sounds, or a murmur similar to the mid-diastolic rumble of mitral stenosis may be heard. These sounds may change when the patient changes position.

Right atrial myxomas rarely produce symptoms until they have grown to be at least 13 cm (about 5 inches) wide.

Tests may include:

• Echocardiogram and Doppler study
• Chest x-ray
• CT scan of chest
• Heart MRI
• Left heart angiography
• Right heart angiography
• ECG—may show atrial fibrillation

Blood tests: A FBC may show anemia and increased WBCs (white blood cells). The erythrocyte sedimentation rate (ESR) is usually increased.

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  Echocardiogram of atrial myxoma

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  Echocardiogram showing atrial myxoma

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  Echocardiogram showing atrial myxoma

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  Atrial myxoma and myocardium. H&E stain.

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  Atrial myxoma. H&E stain.

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  Atrial myxoma. H&E stain.

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  Atrial myxoma covered by endothelium. H&E stain.

Treatment

The tumor must be surgically removed. Some patients will also need their mitral valve replaced. This can be done during the same surgery.

Myxomas may come back if surgery did not remove all of the tumor cells.

Prognosis

An embolized fragment of an atrial myxoma in the iliac bifurcation.

Although a myxoma is not malignant with risk of metastasis, complications are common. Untreated, a myxoma can lead to an embolism (tumor cells breaking off and traveling with the bloodstream). Myxoma fragments can move to the brain, eye, or limbs.

If the tumor continues to enlarge inside the heart, it can block blood flow through the mitral valve and cause symptoms of mitral stenosis or mitral regurgitation. This may require emergency surgery to prevent sudden death.

See also

• Myxoma
• Interleukin 6
• Papillary fibroelastoma
• Rhabdomyomas
• Cardiac sarcomas