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Heart Tumours

What is a tumour?

A tumour is any abnormal mass of the cells that make up the human body. It develops when cells reproduce in an uncontrollable way. It is also called a growth.

Tumour Cell Division
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When genes in a cell change or are missing, cells can make copies of themselves in unpredictable and uncontrollable ways. Tumours may develop.

What is a heart tumour?

Heart tumours can occur inside the heart, in the muscle of the heart, or in the outside wall of the heart. They are very rare.

A heart tumour may start growing in the heart. This is called a primary tumour. Or it may spread (metastasize) to the heart from another part of the body. This is called a secondary tumour. In children, secondary tumours are more common than primary tumours.

Most tumours of the heart are harmless (benign). Most of them occur in children under the age of 12. They have a very good outlook.

The outlook is not as good for cancerous (malignant) tumours. However, these are very rare. Less than 10% of primary heart tumours are malignant. Malignant tumours can invade and destroy tissue in the body. They often cause symptoms that mimic heart disease.

What are the most common benign heart tumours in children?

Rhabdomyomas are the most common heart tumours, followed by fibromas. Both types are benign.


Rhabdomyomas (say: RAB-doe-my-OH-muhs) are found in the inside walls of the heart. They are usually multiple. These tumours are usually seen in children under the age of 1. Often there are no symptoms, but when there are, they can include heart murmur, arrhythmia, and heart failure.

More than 75% of rhabdomyomas are seen in children with tuberous sclerosis. This is a genetic condition marked by lesions of the skin and central nervous system, tumour growth, and seizures.

These tumours usually disappear without treatment and do not become malignant. In general, the outlook is positive.


Fibromas (say: fie-BROE-muhs) usually affect the left ventricle. When these tumours grow, they may get in the way of the mitral and aortic valves, causing valve blockage or leakage. They can also disrupt the heart's electrical system, resulting in arrhythmias. They mainly affect children under the age of 6.

Fibromas may require surgical intervention.

Other benign heart tumours

Less common tumours seen in children are:

  • myxomas, which tend to occur in the atria; they are the most common tumour seen in adults
  • teratomas, which occur in the heart sac
  • lipomas, which are fatty tumours

What are the most common malignant heart tumours in children?

Sarcomas (say: sar-COE-muhs) are malignant heart tumours. These are extremely rare in children. The most common are rhabdomyosarcomas. Other malignant tumours include:

  • angiosarcomas, which can involve any chamber of the heart but most frequently affect the right atrium
  • fibrosarcomas
  • liposarcomas
  • primary lymphomas

Other less common types of malignant tumours include papillary fibroelastomas, hemangiomas, teratomas, lipomas, and lymphomas. These can be primary or secondary.

Symptoms of heart tumours

Sometimes heart tumours do not cause any symptoms. In other cases, they may cause symptoms similar to other heart conditions or defects. These symptoms include heart failure and arrhythmias.

Whether or not a tumour causes symptoms depends on:

  • where the tumour is located in the heart
  • the size of the tumour

Several tests are used to diagnose heart tumours

Tumours in the heart may show no symptoms at all, or they can lead to a malfunction of the heart that is life-threatening. They tend to imitate other heart diseases, which can make it more challenging to make the correct diagnosis.

A heart tumour may be suspected in a child who is known to have cancer already, particularly if she starts having shortness of breath, chest pain, and swelling of the ankles.

Several tests are used to diagnose heart tumours:

  • Often, an echocardiogram (heart ultrasound) is done to outline the tumours. The sound waves pass through the chest wall and provide an image of the heart.
  • Computed tomography (CT) and magnetic resonance imaging (MRI) scans are also used to diagnose tumours in children, but usually after a heart ultrasound has been performed.

How are heart tumours treated?

In some cases, tumours will go away by themselves and no treatment is needed. This is seen mainly in children with rhabdomyomas. If symptoms are severe, though, the doctor will treat the tumour or tumours.

  • Single, noncancerous primary tumours may be surgically removed.
  • When several noncancerous tumours are present, or if the noncancerous tumour is so large that it cannot be removed, they are typically not treated, or heart transplantation may be considered.
  • With both primary and secondary tumours that are cancerous and incurable, only the symptoms can be treated.

Key points

  • Heart tumours may start growing in the heart (primary tumours) or they may metastasize from somewhere else in the body (secondary tumours).
  • There are many different types of heart tumours. Most primary heart tumours are benign (non-cancerous).
  • Heart tumours often mimic the symptoms of other conditions, so they can be hard to diagnose.
  • Treatment depends on the type of heart tumour, its size, and whether it is cancerous.

Fraser Golding, MD, FRCPC