A cardiac myxoma is a rare, benign tumor that originates within the heart, making it the most common type of primary heart tumor in adults. These tumors are typically composed of a gelatinous material and can vary in size from a few millimeters to several centimeters. Though benign, they can lead to serious complications if left unaddressed. Cardiac myxomas most frequently develop in the left upper chamber of the heart, known as the left atrium, often attaching near the fossa ovalis on the interatrial septum.
Symptoms and Complications
Symptoms of a cardiac myxoma are highly varied, depending on the tumor’s size, location, and stability within the heart. These manifestations can be broadly categorized based on their underlying mechanism.
Obstructive symptoms occur when the myxoma blocks blood flow within the heart, mimicking valve stenosis. This can lead to shortness of breath (especially with activity or when lying flat), dizziness, or fainting. If the myxoma is in the left atrium, it can obstruct the mitral valve, leading to symptoms of left-sided heart failure like pulmonary edema.
Myxomas can also cause embolism, where tumor fragments break off and travel through the bloodstream. These fragments can cause blockages in various organs, potentially leading to a stroke if they reach the brain, or issues in the eyes or limbs. Embolic events are a common presenting feature, occurring in 30% to 40% of cases.
Systemic or constitutional symptoms reflect the body’s inflammatory response to the tumor. These general symptoms can include unexplained fever, fatigue, unintentional weight loss, and joint pain. The tumor’s production of inflammatory substances, such as interleukin-6, is thought to cause these widespread symptoms.
Causes and Risk Factors
Most cardiac myxomas (approximately 90%) are “sporadic,” meaning they appear without any identifiable cause or genetic predisposition.
A small proportion (about 7% to 10%) are linked to Carney complex, a genetic condition. This inherited disorder, passed down in an autosomal dominant pattern, involves a higher likelihood of developing multiple myxomas, often in more than one heart chamber, and at a younger age. Individuals with Carney complex may also experience skin pigmentation changes and endocrine system abnormalities.
Cardiac myxomas are generally more common in women (about twice as often as men). They typically manifest in middle-aged adults, with a mean age at diagnosis often ranging between 30 and 60 years. While rare, myxomas can also occur in children.
The Diagnostic Process
Diagnosing a cardiac myxoma typically begins with a thorough medical history and physical examination. During a physical exam, a healthcare provider might detect a distinctive heart sound known as a “tumor plop,” an early diastolic sound caused by the tumor moving into the ventricle. This sound is particularly associated with larger myxomas that prolapse through a heart valve.
The primary diagnostic tool for cardiac myxomas is an echocardiogram, which uses ultrasound waves to create images of the heart. A transthoracic echocardiogram (TTE), performed by placing a transducer on the chest, is often the initial test and can detect about 95% of cardiac masses. For more detailed visualization, especially of smaller tumors or those in less accessible areas, a transesophageal echocardiogram (TEE) may be used. This involves a transducer passed down the esophagus, providing clearer images of the heart’s posterior structures.
To obtain more comprehensive information about the tumor’s size, location, and attachment to the heart wall, advanced imaging tests like computed tomography (CT) scans or cardiac magnetic resonance imaging (MRI) may be employed. These modalities offer detailed anatomical views that assist in surgical planning.
Surgical Treatment and Recovery
Surgical removal is the standard and only effective treatment for cardiac myxomas, as no medical therapies or chemotherapies are available. This intervention is recommended promptly after diagnosis to prevent serious complications such as embolism or obstruction of blood flow within the heart. The procedure typically involves open-heart surgery, performed under general anesthesia, with the patient connected to a heart-lung machine that temporarily takes over the functions of the heart and lungs.
During surgery, the surgeon makes an incision, usually down the center of the breastbone, to access the heart. The myxoma is then carefully resected, along with a small margin of the heart wall where it is attached, to minimize the risk of recurrence. After the tumor is removed, the heart is repaired, and the patient is weaned off the heart-lung machine.
Following successful surgery, patients typically stay in the hospital for several days to a week. The recovery process continues at home, with a gradual return to normal activities over approximately four to six weeks. The prognosis after complete surgical removal is generally excellent, with most patients experiencing a full recovery and returning to their usual lives without restrictions.
The risk of the myxoma recurring is low in sporadic cases (estimated at about 1% to 2%). However, in familial cases or those associated with Carney complex, the recurrence rate can be higher (ranging from 12% to 22%). Regular follow-up echocardiograms, often annually, are recommended to monitor for any potential recurrence.