Heart tumors

Heart tumors – how do they form and who is at risk?

The term heart tumors refers to all growths that form in the heart area. Growths can occur in any part of the heart – the endocardium (the part that lines the inside of the heart), the myocardium (the heart muscle), the heart valves that divide the cavities within the heart, or the pericardium (the heart membrane). Looking at the origin, these can be tumors that arise directly in the heart itself (rather than spreading from another part of the body to the heart) and are therefore called primary heart tumors. Primary heart tumors are usually not malignant, although they can be. In the second case, when cancer cells from another area of the body spread to the heart, these tumors are called metastatic heart tumors. They are always malignant because they are the result of cancer that is already active in the body.

Primary heart tumors

​According to the literature, 75% to 95% of all primary heart tumors are benign. However, despite their benign nature, these tumors can be dangerous if they interfere with the heart's function due to their growth, and they can also increase the risk of stroke if left untreated.

​Some of the more common benign heart tumors are myxoma (the most common benign primary heart tumor, accounting for about 50% of all cases, and most often developing in the left atrium; it must be removed surgically to prevent serious complications such as embolism), papillary fibroelastoma (the second most common benign primary heart tumor, usually diagnosed in people over 60; since it most often grows on the heart valves, surgical removal is recommended due to the high risk of pulmonary embolism), lipoma (a tumor composed of fatty tissue) and hemangioma (a tumor composed of endothelial cells that line the inside of blood vessels). Some specific types, such as rhabdomyosarcoma, can occur in childhood.

​Malignant primary heart tumors are fortunately rare, and among them, various forms of sarcomas (soft tissue tumors) are the most common. The two most common types of cardiac sarcoma are angiosarcoma, which usually arises in the right atrium or pericardium, and rhabdomyosarcoma, which is the most common type of heart tumor in infants and children, but can also develop in adults. Rhabdomyosarcomas arise from so-called mesenchymal cells that develop into cells of the voluntary muscles. When it comes to the heart, they often form in groups and can develop in any of the heart chambers. Other rarer types of malignant primary heart tumors include malignant fibrous histiocytoma and lymphoma. Of particular note is mesothelioma, a malignant tumor that most often arises in the lining of the lungs (the pleura), but can also arise in the pericardium.

Metastatic heart tumors

Although the heart is not a common site of metastatic spread of other malignant diseases, tumors such as melanoma, lymphoma, lung, breast, kidney, and esophageal cancer can spread to the heart.

How common are heart tumors?

​Heart tumors can affect anyone at any age. Some forms (such as teratoma) arise while the fetus is still in the womb. Other forms develop during childhood or at various stages of adulthood. Myxomas are two to four times more common among women. Sarcomas are more common in middle-aged adults. The average age at diagnosis is 44 years.

​Fortunately, primary heart tumors (both benign and malignant) are rare, affecting less than 1 in 2,000 people. Benign tumors, as previously emphasized, are much more common than malignant ones.

​Metastatic heart tumors are more common than primary ones, but they are still rare. However, it can happen that a tumor that arises in an organ near the heart during its growth directly affects the heart through local spread. According to available data, this happens in as many as 10% of people with lung cancer or breast cancer. Of the distant tumors that metastasize to the heart, melanomas are the most common.

Figure 1. Anatomy of the heart. It consists of 2 atria that are connected to the ventricles. Between the ventricles and the atria, as well as at the exits of the atria, are heart valves that regulate blood flow.

Can I recognize a heart tumor?

​Possible symptoms depend on the type of tumor, its size, and its location. Malignant tumors can spread to other organs, such as the lungs. Benign heart tumors do not metastasize, but they can cause various heart problems as they grow. For example, tumors that grow in the area of the heart valves can obstruct blood flow in the heart or lead to blood clots. Heart muscle tumors can cause heart failure or arrhythmia. Some people have no symptoms or they are very mild. Others have symptoms that signal life-threatening heart problems.

​However, most symptoms are nonspecific, meaning that many different health problems can cause them, not just heart tumors. Of course, it is always important to inform your doctor about the symptoms you are experiencing so that their cause can be clearly defined. In general, people with malignant heart tumors have symptoms that start suddenly and worsen quickly, while the symptoms of benign tumors usually develop gradually. Some of the possible symptoms include chest discomfort, dizziness and fainting, fatigue, fever and chills, palpitations, loss of appetite, night sweats, shortness of breath, and the like.

How is a heart tumor diagnosed?

​Heart tumors are diagnosed with imaging tests. Primary heart tumors are often difficult to diagnose because their signs and symptoms are similar to those of various other conditions. The tumor is usually suspected in people who have symptoms of heart failure without a clear cause, or the disease is discovered accidentally as part of the workup for another disease.

​One of the main tests is an ultrasound of the heart (echocardiography). It can be done in a standard way (transthoracic echocardiography), in which the doctor places a probe on the skin of the chest as in a routine ultrasound examination of other parts of the body. This test is useful for finding tumors in the ventricles (lower chambers of the heart). Another option is a transesophageal echocardiogram, where a probe is inserted through the esophagus to get close to the heart, which is useful for finding tumors in the atria (upper chambers of the heart).

​A magnetic resonance imaging (MRI) of the heart helps identify details about the tumor, such as whether it is malignant or benign. A contrast-enhanced CT scan of the heart is useful for people who have implanted devices (such as a pacemaker) and cannot undergo an MRI. It is also valuable for evaluating the entire chest area (including the lungs and blood vessels).

Is there any treatment?

​Treatment options for heart tumors vary depending on the type of tumor. In general, the prognosis depends on the type of tumor and the stage of the disease at diagnosis. In general, earlier diagnosis leads to better outcomes.

Benign primary heart tumors are usually successfully treated with surgery if they are small. Larger tumors may not be able to be removed.

Malignant primary cardiac tumors usually cannot be removed surgically and are often fatal. These tumors spread rapidly or come back after treatment. Chemotherapy or radiotherapy can be used to slow the progression of the cancer. About 50% of patients are alive one year after diagnosis, and only about 19% survive 5 years. However, there are significant differences here. People with sarcoma survive an average of nine to 17 months after diagnosis, while with paraganglioma over 80% of patients survive 10 years after successful surgery.

For metastases to the heart, treatment depends on the primary site of the cancer, that is, the underlying disease that led to the metastases to the heart is treated. It may include systemic treatment such as chemotherapy and targeted drugs, or surgical removal of the tumor.

Continue reading: Pseudomyxoma of the peritoneum

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