Cardiac tumors are abnormal growths of tissue that develop on or within the heart structure. These masses can be either non-cancerous (benign) or cancerous (malignant). They are exceptionally rare compared to malignancies in other organs, with an estimated incidence of approximately 1 in 3,000 individuals. Determining the presence and type of a heart mass requires specialized clinical evaluation and advanced imaging.
Primary Versus Secondary Cardiac Tumors
When a growth is found in the heart, the medical team first determines its origin. A primary cardiac tumor starts directly in the heart tissue, while a secondary or metastatic tumor has spread from cancer located elsewhere in the body. Primary cardiac malignancies are exceedingly rare, accounting for only about 10% to 25% of all tumors that originate in the heart.
The vast majority of primary cardiac tumors—approximately 75% to 90%—are benign. The most common is the atrial myxoma, which frequently develops in the left upper chamber of the heart. Secondary cardiac tumors are significantly more prevalent, often found to be 10 to 100 times more common than primary malignant tumors. These metastatic lesions typically originate from cancers of the lung, breast, melanoma, or lymphomas that have spread through the bloodstream or by direct extension.
Clinical Signs and Manifestations
Symptoms associated with a heart mass are notoriously vague and often mimic common cardiovascular conditions, such as heart failure or valvular disease. This nonspecific presentation frequently delays diagnosis. The patient experience is heavily influenced by the tumor’s size, location, and growth rate.
Symptoms often arise from physical obstruction of normal blood flow through the heart chambers or valves. Patients may experience shortness of breath, especially when lying flat, or swelling in their legs and abdomen due to blood backing up. Intermittent blockage of a valve opening can lead to episodes of dizziness or fainting (syncope).
A tumor infiltrating the heart muscle can interfere with the organ’s electrical system, leading to rhythm disturbances. This may cause palpitations or serious arrhythmias. Fragments from the tumor’s surface can break off and travel through the circulation, potentially causing a stroke or blockage of blood flow to distant organs.
Beyond direct cardiac effects, some tumors cause systemic symptoms resembling an infection or an autoimmune disorder. These manifestations include unexplained fevers, fatigue, joint aches, and unintentional weight loss. A benign atrial myxoma, for instance, sometimes presents with these constitutional symptoms, complicating diagnosis.
Confirmatory Diagnostic Procedures
Confirmation begins with a non-invasive screening tool, typically a transthoracic echocardiogram. This ultrasound uses sound waves to create real-time images, identifying abnormal masses, their size, and location within the heart chambers or on the valves. While the echocardiogram establishes the mass’s existence, it cannot definitively determine its cancerous nature.
Following detection, advanced cross-sectional imaging characterizes the mass and its relationship to surrounding structures. Cardiac Magnetic Resonance Imaging (MRI) is particularly valuable for its superior soft-tissue contrast. This allows doctors to assess the tumor’s internal characteristics, such as fat, blood, or necrotic tissue content. MRI can also assess the function of the heart muscle and blood flow patterns.
A Computed Tomography (CT) scan is often used with MRI, especially when evaluating for potential secondary tumors or assessing disease spread outside the heart. Both CT and MRI utilize “ECG gating” to synchronize image acquisition with the heartbeat. This technique reduces motion blur and provides clearer pictures of the rapidly moving organ. These imaging studies strongly suggest a diagnosis, but they remain indirect evidence.
The definitive diagnosis requires a tissue sample (biopsy) examined under a microscope. This procedure is complex and depends on the tumor’s location; sometimes, a small sample is obtained via a specialized catheter (endomyocardial biopsy). Due to the high risk, a biopsy is often only performed if the tumor cannot be surgically removed or if the tissue diagnosis fundamentally changes the treatment plan. For many primary tumors, the mass is removed surgically, and the entire specimen is sent for pathological analysis to confirm the diagnosis.