What is Cardiac Fibroma?
Primary cardiac tumors, or tumors that first form in the heart, are quite uncommon, occurring in only about 0.03% to 0.32% of cases. 75% of these heart tumors are benign, meaning they are not cancerous. In children, the second most common type of primary heart tumor is called a cardiac fibroma, after a kind of tumor called a rhabdomyoma.
Cardiac rhabdomyomas and fibromas are classified as types of hamartomas, non-cancerous overgrowth of normal cells. Cardiac fibromas primarily consist of connective tissue and fibroblasts which are a type of cell that helps in maintaining the structural integrity of the heart. Despite being benign, cardiac fibromas can still cause symptoms due to blockage within the heart, obstruction of the blood flow in and out of the heart, compromised heart arteries, and increased risk of blood clots. These tumors can cause issues with the heart’s electrical signaling and in rare cases can even lead to sudden death.
Pediatric heart tumors often show up alongside genetic conditions. For instance, rhabdomyoma is linked to a genetic condition known as tuberous sclerosis. Meanwhile, around 3% to 5% of people with a genetic disorder called Gorlin or Gorlin-Goltz syndrome, also referred to as nevoid basal cell carcinoma syndrome, present with cardiac fibromas.
What Causes Cardiac Fibroma?
Cardiac fibroma, a heart condition, is sometimes linked with Gorlin-Goltz syndrome. This syndrome – also known as nevoid basal cell carcinoma syndrome – is a genetic disorder, although not all patients with cardiac fibroma fully exhibit its symptoms.
Gorlin-Goltz syndrome is a complex, genetic condition that passes down through families. It arises from mutations or changes in certain genes called PTCH1 or SUFU. Located on chromosome 9q22.3, these important genes help suppress tumor growth by blocking a biological mechanism known as the Hedgehog signaling pathway.
This syndrome isn’t very common, with estimates suggesting it affects 1 in 57,000 to 1 in 164,000 people. It equally affects men and women, and occurs in about 1 in 19,000 live births. As it’s inherited in an ‘autosomal dominant’ manner, it usually comes from one parent who has the disease. Nonetheless, in 20% to 30% of cases, the disease can occur spontaneously, with no previous family history.
Risk Factors and Frequency for Cardiac Fibroma
As per the World Health Organization’s 2021 report, cardiac fibroma, a type of heart tumor, is mostly found in children, making up around 90% of all cases. These tumors are usually identified in babies or while the baby is still in the womb. Despite being most common in infants within their first year, cardiac fibromas can also occur in individuals with a specific condition called nevoid basal cell carcinoma syndrome and have been found in such individuals up to age 60.
Cardiac fibromas are the second most frequently identified benign (non-cancerous) heart tumor in children, with a rhabdomyoma being the most common. They’re also frequently discovered in fetuses as the second most common tumor, likely due to prenatal testing. Early detection and frequent monitoring are crucial for controlling cardiac fibromas in children and even before birth during prenatal care.
Signs and Symptoms of Cardiac Fibroma
Cardiac fibromas are conditions that can sometimes show no symptoms. However, when symptoms do appear, they are usually determined by where the tumor is located in the heart. Common symptoms include:
- Heart murmurs
- Irregular heart rhythms (arrhythmias)
- Heart failure
- Sudden death
Another condition, called Nevoid basal cell carcinoma syndrome, can show different signs. These usually include lamellar or early calcification of the falx (rigid structure in the brain), keratocysts in the jaw, pits in the palms of the hands or soles of the feet, and a higher chance of getting basal cell carcinomas (a type of skin cancer). Other distinct signs include having a larger than normal head (macrocephaly), bulging of the forehead (frontal bossing), and eyes that are spaced wider than usual. This syndrome can also come with skeletal anomalies, childhood medulloblastoma (a type of brain tumor), cleft lip or palate, and occasionally, ovarian fibromas in girls.
Testing for Cardiac Fibroma
Fibromas are masses that don’t move, and can be found in the wall of the heart’s main pumping chamber. These can be spotted using an ultrasound of the heart. When examined with a CT scan, they typically look like even masses that resemble the texture of soft tissue and may show hardened areas known as calcifications.
For a more detailed view, a type of MRI scan is used. On one type of MRI image (T1-weighted), fibromas may appear as well-defined areas that either match or are more intense than the surrounding heart tissue. On another type of MRI image (T2-weighted), these areas appear less intense.
Generally, fibromas do not appear more visible following the injection of a contrast dye. However, in some instances, biopsy (a sample of tissue collected for testing) is not needed for diagnosis when the patient’s symptoms and MRI results match up.
Looking at an electrocardiogram (ECG), a test that checks your heart’s electrical activity, most patients with fibromas will often show unusual T-wave patterns. These patterns are generally in line with an origin near the tumor site. In adults, these fibromas may show up on heart scans as unchanging defects.
Treatment Options for Cardiac Fibroma
Cardiac fibromas are rare heart tumors that usually occur in children, affecting roughly 1 in every 280,000 births. Because they’re so uncommon, there’s still a lot to learn about how best to treat them, which makes them a challenge for heart specialists. There are several potential treatment approaches, including surgery to remove the tumor, a complicated heart procedure called single ventricle palliation, a heart transplant, or simply managing the condition with heart rhythm medications.
One possible treatment method to consider is placing a defibrillator, a device that can correct dangerous heart rhythms. However, for babies, installing a defibrillator is risky and should only be considered after other options have been ruled out and after a thorough discussion of the potential rewards and hazards. One approach is to have the defibrillator lead (the wire that connects the defibrillator to the heart) go around the back of the heart in the epicardial space (the outer layer of the heart), along with two extra leads to control the heart’s pace. A second option is to also use leads to control the pace, but instead of placing the defibrillator lead around the back of the heart, it is run along the space between the ribs. However, this approach has a high risk of lead fracture, with half reported to fail within five years.
Treating the disease with medications such as amiodarone and beta-blockers has proven effective, especially for smaller tumors located at the tip of the heart. These medications can control irregular heart rhythms, potentially eliminating the need for a defibrillator altogether. Additionally, surgical tumor removal is an option that can cure the patient, also avoiding the need for a long-term defibrillator or medication. This method can be used for large tumors and typically has positive results. However, there are only a handful of heart centers with the necessary experience to perform this type of surgery.
Surgery is generally recommended for children aged between 1 and 3. Doctors take into consideration the severity of irregular heart rhythms, how well medications are tolerated, the condition of any defibrillator leads, and symptoms before deciding on surgery. Although the size and position of the tumor can make surgery tricky, the risks are relatively low.
For patients whose tumors cannot be removed because they’re too large or spread out, other solutions have been reported. These include single ventricle palliation, a heart procedure that simplifies the circulation when one ventricle (one of the two larger chambers in the heart) is ineffective. In a case where a large tumor was in the right ventricle, doctors performed a process that facilitated blood flow to the left atrium and left ventricle, aiding both systemic (whole body) and pulmonary (lung) circulation. Techniques like this can act as a step towards a heart transplant for patients who cannot have their cardiac fibromas surgically removed.
What else can Cardiac Fibroma be?
When a doctor is trying to diagnose a cardiac fibroma, they consider and rule out other similar conditions like:
- Cardiac Rhabdomyoma: Calcification generally helps to differentiate between a cardiac fibroma and a rhabdomyoma.
- Myxomas: They differ from cardiac fibromas as they are generally found in the atrium of the heart and often have a stalk. On the other hand, fibromas are located within the heart’s muscle and are mainly found in the ventricles, lacking a stalk.
- Teratomas
- Lipomas: These tumors are often found on the outer layer of the heart. They’re usually multiple and enclosed primary heart tumors, compared to cardiac fibromas, which are usually a single tumor located within the heart’s muscle.
- Hemangiomas: These usually have a lot of blood vessels, which cardiac fibromas do not.
Surgical Treatment of Cardiac Fibroma
Stereotactic radiosurgery, a type of non-invasive procedure that uses multiple beams of radiation to treat a specific area, has been mentioned as a method for managing ventricular arrhythmias. Ventricular arrhythmias refer to abnormal heart rhythms that originate in the lower chambers of the heart, while cardiac fibromas are non-cancerous tumors in the heart’s muscle tissue that can’t be surgically removed. However, not all medical experts universally accept this treatment approach.
What to expect with Cardiac Fibroma
In babies, heart fibromas, which are non-cancerous heart tumors, can be problematic if they are too large or have spread deeply into the heart muscle, making them impossible to remove through surgery. This could lead to a poor outlook and might require tactics like inserting a device to control irregular heartbeats (a defibrillator) or even replacing the problematic heart through a heart transplant.
On the other hand, if the tumors can be removed by surgery, even if the removal is not complete, the outlook is usually quite good. A study showed that patients with heart fibromas who had successful surgery lived for an average of 27 years after their operation.
Possible Complications When Diagnosed with Cardiac Fibroma
If cardiac fibromas, which are heart tumors, aren’t treated, they can increase the chance of a fatal outcome. This is mainly because they can lead to extremely dangerous heart rhythms known as ventricular arrhythmias. Spotting these fibromas early and seeking the right medical treatment is essential for managing the condition and reducing the associated dangers.
Preventing Cardiac Fibroma
If you’ve been diagnosed with a condition called nevoid basal cell carcinoma syndrome, which is commonly seen in people who also have heart growths called cardiac fibromas, you need to be aware of the associated risks. Given this condition, you’re more likely to develop a type of skin cancer called basal cell carcinoma. To reduce your risk, it’s very important that you regularly use sunscreen, try to limit the time you spend in the sun, and steer clear of ionizing radiation, which is a type of radiation that can cause damage to cells.
