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Overview of Heart Tumors
A tumor is any type of abnormal growth, whether cancerous (malignant) or noncancerous (benign). Tumors in the heart may be
Primary heart tumors are tumors that originate in the heart. Primary heart tumors are rare, occurring in fewer than 1 of 2,000 people.
Metastatic heart tumors are cancers that developed in another organ and then spread to the heart. Most heart tumors are metastatic cancer.
Both primary and metastatic tumors may develop in the sac that surrounds the heart (pericardium). Tumors in the pericardium may squeeze (constrict) the heart, preventing it from filling properly. Chest pain and heart failure may develop.
In adults, about half of noncancerous primary heart tumors are myxomas. Myxomas usually develop in the heart's left upper chamber (atrium). They may develop from embryonic cells located in the inner layer (lining) of the heart's wall.
In infants and children, the most common type of noncancerous primary heart tumor is a rhabdomyoma. Rhabdomyomas, which typically occur in groups, usually grow within the heart wall and develop directly from the heart's muscle cells. Rhabdomyomas commonly develop during infancy or childhood, often as part of a rare disease called tuberous sclerosis.
The second most common noncancerous primary tumors in infants and children are fibromas. Fibromas, which typically occur as a single tumor, usually grow on heart valves and develop from the heart's fibrous tissue cells.
Several other types of primary heart tumors can develop, but all are rare. Some are cancerous and some benign.
Types of Noncancerous Heart Tumors
Cancerous primary heart tumors include sarcoma, mesothelioma, and primary lymphoma.
Sarcomas are the second most common primary heart tumor (after myxoma). They develop in the right or left atrium and can block blood flow through the heart. Tumors in the right atrium can spread to the lungs.
Mesothelioma most often develops in the membrane the covers the lungs (pleura). However, mesothelioma rarely can develop in the membrane that covers the heart (pericardium). Pericardial mesothelioma can spread to the spine and brain.
Lymphoma is a cancer of white blood cells known as lymphocytes. Lymphoma usually develops in the lymph nodes, spleen, and/or bone marrow. Lymphoma that develops in the heart is extremely rare. It usually occurs in people who have AIDS and grows rapidly. Lymphoma can also metastasize to the heart.
Metastatic heart tumors originate in some other part of the body—usually the lungs, breasts, kidneys, blood, or skin—and then spread (metastasize) to the heart. They are always cancerous. Metastatic heart tumors are 30 to 40 times more common than primary heart tumors but are still uncommon. About 10% of people who have lung or breast cancer—two of the most common cancers—and about 75% of people with malignant melanoma have metastases to the heart.
Heart tumors may cause no symptoms, minor symptoms, or symptoms of life-threatening heart malfunction.
Major symptoms include
Minor symptoms may include
Heart murmurs develop in about half of the people who have tumors that develop near or on a heart valve (such as myxomas and fibromas) because blood does not flow through the valve normally.
Noncancerous tumors can be as deadly as cancerous ones if they interfere with the function of the heart.
Heart tumors, especially myxomas and sometimes fibroelastomas (fibromas), may degenerate so that pieces of them break off and travel through the bloodstream (becoming emboli). Emboli may lodge in small arteries and block blood flow. Also, blood clots that form on the surface of tumors, such as myxomas, may break off as emboli and block arteries. Symptoms due to emboli depend on where the clot goes and therefore which tissues or organs are affected by the blocked artery.
Primary heart tumors are difficult to diagnose because they are relatively uncommon and because their symptoms resemble those of many other disorders. Doctors may suspect a primary heart tumor in people who have heart murmurs, abnormal heart rhythms, unexplained symptoms of heart failure, or unexplained fever (which may be due to a myxoma). Secondary heart tumors are suspected when people who have cancer elsewhere in the body come to a doctor with symptoms of heart malfunction.
If a tumor is suspected, echocardiography is usually done to confirm the diagnosis. For this procedure, a probe that emits ultrasound waves is passed over the chest, producing an image of heart structures. If another view of the heart is needed, the probe can be passed down the throat into the esophagus to record signals from just behind the heart. This procedure is called transesophageal echocardiography.
Computed tomography (CT) or magnetic resonance imaging (MRI) can provide additional information and can often distinguish noncancerous from cancerous tumors. Coronary angiography can produce an outline of a heart tumor that can be seen on x-rays, but this procedure is rarely needed.
Unlike with tumors in most other parts of the body, doctors rarely do a heart biopsy (taking a tissue sample to look at it under a microscope). Heart biopsy may be dangerous depending upon the location of the tumor), and doctors can usually tell the difference between benign and cancerous heart tumors from the results of imaging tests.
A single small noncancerous primary heart tumor can be surgically removed, usually resulting in a cure. If a large noncancerous primary tumor is significantly reducing blood flow through the heart, removal of the part of the tumor that does not grow into the heart wall may improve heart function. However, if a large part of the heart wall is involved, surgery may be impossible.
Rhabdomyomas regress without treatment in about half of affected newborns. In the other half, the tumors do not grow any larger and do not require treatment.
In infants and children, a fibroma that does not affect the wall between the ventricles (septum) may be successfully removed. Tumors that affect this wall usually also affect the electrical conduction system of the heart and cannot be surgically removed. Children with this type of tumor usually die of an abnormal heart rhythm at an early age. If a fibroma is large, blocks blood flow, and has grown into the surrounding tissue, heart transplantation may be required.
Transplantation is very rarely done in either children or adults, and only noncancerous tumors are typically considered for heart transplantation. Mechanical cardiac support might be considered until doctors can determine whether heart transplantation is appropriate.
Noncancerous tumors in the pericardium can be removed surgically, but cancerous tumors are not removed because they have usually already spread elsewhere in the body. If the tumor secretes fluid that interferes with heart motion, this fluid can be drained with a small plastic tube inserted by needle into the space between the pericardium and the heart (the pericardial space). Sometimes drugs are injected into the pericardial space to slow the tumor's growth.
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