What Is Cardiac Rhabdomyoma? A Complete Guide for Parents and Expectant Families
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: Is cardiac rhabdomyoma cancerous?
Cardiac rhabdomyomas are benign heart tumors that do not spread and are the most common type of heart tumor in fetuses and children, usually appearing before or shortly after birth. [4] In the vast majority of cases they shrink and resolve on their own without treatment. [2] [4] Because most affected children also have tuberous sclerosis, further evaluation and follow-up are recommended. [4]
Key takeaways
Cardiac rhabdomyomas are benign heart muscle tumors and the most common fetal cardiac tumor, though heart tumors overall are rare. [4]
They typically appear during pregnancy or within the first year of life and form in clusters within the heart's lower chambers. [4]
Most tumors shrink and disappear on their own after reaching their largest size at birth. [4] Treatment is rarely needed. [4]
Cleveland Clinic reports that at least 8 in 10 children with cardiac rhabdomyoma also have tuberous sclerosis, a rare genetic disorder. [4] Other published estimates are lower, so the exact figure varies.
Symptoms are rare, but a sudden change in heart rhythm, fast heart rate, breathing difficulty, fainting, or swelling should prompt immediate emergency care. [4]
What the research says
Most tumors regress, and TSC is closely linked. In a single-center series of 12 fetuses diagnosed with cardiac rhabdomyoma by fetal echocardiography (53 tumors in total), tuberous sclerosis complex was diagnosed in every patient during follow-up, and tumors regressed during the first year of life in the four pregnancies that continued. The authors note that large tumor size, high tumor number, and certain locations were linked to hydrops and poorer newborn outcomes. This is a very small study, so it illustrates the pattern rather than proving it (Bejiqi et al., Open Access Maced J Med Sci, 2017) [1].
When treatment is needed, targeted medicines have been used. A systematic review of 30 articles describing 41 children with tuberous sclerosis complex found that 33 (80.5%) had symptomatic rhabdomyomas. mTOR inhibitors (everolimus or sirolimus) led to clinical improvement in 30 of those 33 (90.9%), and tumor size reduction was reported in 95.1%. Some tumors regrew after the medicine was stopped, side effects were mostly mild, and the evidence comes mostly from case reports, with no randomized trials (Sugalska et al., Int J Environ Res Public Health, 2021) [2].
What Is Cardiac Rhabdomyoma?
A cardiac rhabdomyoma is a noncancerous (benign) tumor that forms in the heart muscle. While heart tumors of any kind are rare, cardiac rhabdomyomas are the most common type found in fetuses and children. [4] They often develop during pregnancy or within the first year of life. [4]
These tumors grow directly from the heart muscle itself and typically appear in clusters of multiple nodules. That clustering is a defining feature. It sets rhabdomyomas apart from fibromas, another benign heart tumor type that appears only as a single mass rather than a group. [4]
Cardiac rhabdomyomas are not malignant and do not spread to other parts of the body. [4] They only become dangerous when they interfere with the heart's normal function, which is uncommon. [4] Most of the time, these tumors simply fade away on their own without causing any serious problems.
The tumors can develop on either side of the heart. They are usually located in the right ventricle or left ventricle, the heart's lower chambers. Occasionally, they form in the atria (upper chambers) or in the septum, the wall separating the ventricles. [4] Size varies from just a few millimeters to several centimeters, and the tumors appear yellow or white when viewed directly. [4]
How Common Is It?
Heart tumors that originate within the heart itself, called primary cardiac tumors, affect fewer than 1 in 2,000 people. [4] Within that already rare group, cardiac rhabdomyomas stand out as the most frequently diagnosed type in developing fetuses and children.
Who Gets Cardiac Rhabdomyoma?
Babies and children with tuberous sclerosis are significantly more likely to develop cardiac rhabdomyomas. [3] [4] Research shows no differences in occurrence based on sex, ethnicity, or race. [4]
Factor | Detail |
Tumor type | Benign (noncancerous), never spreads |
Typical timing | During pregnancy or within first year of life |
Pattern | Clusters of nodules in the heart muscle |
Common locations | Right or left ventricle; sometimes atria or septum |
Size range | A few millimeters to several centimeters |
Visual appearance | Yellow or white |
Overall rarity | Primary heart tumors affect fewer than 1 in 2,000 people |
Association with tuberous sclerosis | At least 8 out of 10 cases, according to Cleveland Clinic (other estimates are lower) |
Symptoms of Cardiac Rhabdomyoma
Most cardiac rhabdomyomas produce no symptoms at all. Many are discovered by chance during routine prenatal imaging. Problems arise only when a tumor or cluster of tumors interferes with the heart's structure or electrical system, which is rare. [4]
Larger tumors can block blood flow or disrupt the heart's rhythm. [4] When this happens during pregnancy, it can seriously affect the developing fetus and may lead to heart failure or a condition called hydrops, in which fluid builds up abnormally in the fetal body. [1] [4] Healthcare providers use imaging tests during pregnancy to watch for signs of these complications.
In babies and children, tumors that grow or fail to resolve can occasionally lead to heart failure or arrhythmia. [2] [4] Doctors monitor these children closely so any developing problem is caught early.
Warning Symptoms That Need Immediate Attention
While symptoms are rare, certain signs should never be ignored in a child. Seek emergency medical care (call 911) if a child shows any of the following: [4]
Emergency symptom | What it may indicate |
Change in heart rhythm | Tumor disrupting the heart's electrical system |
Fast heart rate (tachycardia) | Arrhythmia triggered by the tumor |
Trouble breathing, especially when lying down (dyspnea) | Impaired blood flow affecting the lungs |
Chest pain or tightness relieved by sitting up | Pressure on the heart or surrounding structures |
Coughing | Fluid-related complications |
Dizziness or fainting | Inadequate blood flow to the brain |
Fatigue or weakness | Reduced heart output |
Swollen legs, ankles, or belly | Fluid retention from heart failure |
What Causes Cardiac Rhabdomyoma?
Cardiac rhabdomyomas are most likely caused by genetic changes that occur before birth. These changes often lead to tuberous sclerosis, a rare genetic disorder that affects approximately 1 in 6,000 newborns in the United States. [4]
People with tuberous sclerosis carry mutations in the TSC1 or TSC2 gene. [4] Both genes normally work to suppress tumor formation. Because most children with cardiac rhabdomyomas have tuberous sclerosis, the tumor is often the first visible clue that the genetic condition is present. [2] [4]
Some children develop a cardiac rhabdomyoma without tuberous sclerosis. In those cases, the underlying cause of the tumor remains unknown. [4]
Congenital vs. Hereditary
Cardiac rhabdomyoma is usually congenital, meaning present at birth. But congenital is not the same as hereditary. A hereditary condition is passed down through a family's genes across generations, and cardiac rhabdomyomas are often not hereditary. [4]
Concept | Meaning |
Congenital | Present at birth, regardless of how it arose |
Hereditary | Passed down through family genes |
Tuberous sclerosis can be inherited, but often it is not. A parent with tuberous sclerosis has a 50% chance of passing the condition to a child. [4] However, this inherited pattern explains only about 1 in 3 tuberous sclerosis cases. [4] The remaining cases arise spontaneously, with no family history at all, when the genetic mutation appears for the first time in the newly diagnosed baby.
This means cardiac rhabdomyomas can appear both predictably, in families with a known history, and completely out of the blue.
How Is Cardiac Rhabdomyoma Diagnosed?
Imaging tests make the diagnosis, either during pregnancy or after birth. Because the tumors often cause no symptoms, imaging is what brings them to light.
Tests Used Before Birth
The tumor is frequently first spotted on a routine prenatal ultrasound, where it becomes visible between weeks 20 and 30 of pregnancy. [4] It can also be diagnosed through a fetal echocardiogram, a specialized ultrasound that examines the developing fetal heart in detail. [1] [4]
Tests Used After Birth
Once a baby is born, several tests can confirm and evaluate the tumor:
Test | What it does |
Electrocardiogram (EKG) | Records the heart's electrical activity to detect rhythm problems |
Echocardiogram (echo) | Uses ultrasound to visualize the heart's structure and tumor location |
Magnetic resonance imaging (MRI) | Provides detailed images of the heart muscle and surrounding tissue |
Because these tumors usually shrink over time, a child may need regular EKGs and echocardiograms so the provider can confirm the tumors are resolving. [4] Tumors that do not go away on their own will need treatment.
Checking for Tuberous Sclerosis
Since a cardiac rhabdomyoma is often the first sign of tuberous sclerosis, the diagnosed child will likely need further testing to look for signs of the condition in other parts of the body. [4]
If tuberous sclerosis is confirmed, genetic testing becomes an important conversation. Sometimes parents carry a mild, never-diagnosed form of the condition. For that reason, providers may recommend testing both parents to see whether either carries the genetic mutation that caused it. [4]
Treatment for Cardiac Rhabdomyoma
Most cardiac rhabdomyomas go away on their own and never need treatment. In the typical course, the tumors reach their largest size around the time a baby is born. [4] After that, they shrink gradually on their own without causing problems. [4]
Treatment is considered only in the uncommon situations where a tumor disrupts heart function. This can happen during pregnancy, in which case the mother may receive medication intended to shrink the tumor. [4] It can also happen after birth, when a tumor that has not resolved, or continues to grow, threatens the child's heart function and raises the risk of heart failure or arrhythmia. [4]
Medication Options
When treatment is needed, providers typically turn to medications rather than surgery: [4]
Medication type | Purpose |
ACE inhibitors | Reduce strain on the heart and help it pump more efficiently |
Diuretics | Help the body remove excess fluid |
Anti-arrhythmic medication | Stabilize the heart's rhythm |
mTOR inhibitors (everolimus, sirolimus) | Targeted medicines used for benign heart tumors such as rhabdomyoma, particularly in children with tuberous sclerosis |
The National Cancer Institute lists everolimus and sirolimus among the targeted therapies used to treat benign heart tumors. [3] As the research above notes, most of the evidence for these medicines comes from case reports rather than large trials [2], so the decision is made case by case by the child's specialists.
A child's healthcare provider will discuss the available options with the family and help choose the plan that best fits the child's situation. Surgery is rarely needed for cardiac rhabdomyomas. [4]
Outlook and Prognosis
Most people with cardiac rhabdomyoma never need treatment [4], and the overall outlook is favorable. The tumors usually shrink and resolve on their own without lasting harm.
The presence of other conditions, especially tuberous sclerosis, shapes the longer-term outlook. Children with tuberous sclerosis need regular medical checkups and tests. For some people, tuberous sclerosis is mild and barely noticeable. For others, it can cause serious complications that meaningfully affect quality of life. [4]
A child's healthcare provider will explain their specific medical needs and prognosis, and together the family and care team will develop the best possible care plan.
Questions to Ask Your Child's Doctor
Receiving any diagnosis for your child, and especially a fetal diagnosis during pregnancy, can feel overwhelming. Providers anticipate most questions, but coming prepared helps. The following questions are a useful starting point for families navigating a cardiac rhabdomyoma diagnosis.
Question | Why it matters |
How can we monitor my child's rhabdomyoma? | Establishes the follow-up imaging schedule |
Will my child need medicine or surgery? | Clarifies whether treatment is likely |
Does my child have tuberous sclerosis? | Determines the broader care pathway |
How will tuberous sclerosis affect my child? | Connects the tumor to the child's overall health |
Should I have genetic testing for tuberous sclerosis? | Identifies whether a parent carries the mutation |
Can you connect me with a tuberous sclerosis support group? | Links the family to community and resources |
A note of reassurance is worth adding here. When a child is diagnosed with a medical problem, it can feel scarier than being diagnosed yourself. But with the right resources and a solid monitoring plan, most families manage cardiac rhabdomyomas with watchful waiting, and that approach is usually all that is needed.
Conclusion
Cardiac rhabdomyoma sounds alarming, but it is a benign tumor that almost always resolves on its own. It is the most common fetal heart tumor, usually appears before or shortly after birth, and typically reaches its largest size around the time of delivery before shrinking away without treatment. The strongest association is with tuberous sclerosis, a genetic condition present in most affected children, which is why genetic counseling and family testing often follow the diagnosis. Watchful waiting with regular imaging is the usual path, and only rarely do medications or surgery become necessary.
If a prenatal scan has revealed a fetal heart tumor, or if your child's imaging shows nodules in the heart muscle, partner closely with a pediatric cardiologist. Clear communication, scheduled follow-ups, and awareness of the rare warning symptoms give your family the best possible footing.
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Frequently Asked Questions
What is a cardiac rhabdomyoma?
A cardiac rhabdomyoma is a noncancerous (benign) tumor that forms in the heart muscle. [4] It is the most common type of heart tumor in fetuses and children, although heart tumors are rare overall. [4]
Is cardiac rhabdomyoma cancer?
No. Cardiac rhabdomyomas are benign tumors. They do not spread to other parts of the body and are never considered malignant. [4]
Are cardiac rhabdomyomas dangerous?
Usually not. They become dangerous only when they disrupt the heart's normal function, such as by blocking blood flow or disturbing heart rhythm, which is rare. [4]
Can cardiac rhabdomyoma go away on its own?
Yes. In most cases, the tumors reach their largest size around birth and then shrink and disappear on their own without any treatment. [4]
When do cardiac rhabdomyomas appear?
Cardiac rhabdomyomas typically appear during pregnancy (in the uterus) or within the first year after birth. [4]
Are cardiac rhabdomyomas congenital?
Yes, a cardiac rhabdomyoma is usually present at birth, which makes it congenital. However, congenital does not automatically mean hereditary. [4]
Are cardiac rhabdomyomas hereditary?
Cardiac rhabdomyomas can be, but often are not. [4] The genetic disorder most often associated with these tumors, tuberous sclerosis, frequently arises with no family history at all. [4]
What causes cardiac rhabdomyoma?
The tumors are likely caused by genetic changes that happen before birth, usually leading to tuberous sclerosis. [4] In children without tuberous sclerosis, the cause is unknown. [4]
What is the connection between cardiac rhabdomyoma and tuberous sclerosis?
According to Cleveland Clinic, at least 8 out of 10 people with cardiac rhabdomyomas also have tuberous sclerosis [4], although other published estimates are lower. In many cases, the heart tumor is the first sign of the genetic condition. [2] [4]
What is tuberous sclerosis?
Tuberous sclerosis is a rare genetic disorder that affects about 1 in 6,000 newborns in the United States. [4] It is caused by mutations in the TSC1 or TSC2 genes [4], which normally suppress tumor formation.
Do all children with cardiac rhabdomyoma have tuberous sclerosis?
No. Most do, but some children develop the tumor without tuberous sclerosis. In those cases, the underlying cause remains unknown. [4]
Can cardiac rhabdomyomas run in families?
Cardiac rhabdomyomas can, when a parent has tuberous sclerosis. A parent with the condition has a 50% chance of passing it on. [4] However, inherited cases explain only about 1 in 3 tuberous sclerosis cases. [4] The rest arise spontaneously in the child.
Who gets cardiac rhabdomyoma?
Cardiac rhabdomyomas occur most often in babies and children, particularly those with tuberous sclerosis. [3] [4] Research shows no differences based on sex, ethnicity, or race. [4]
How common are heart tumors in general?
Primary cardiac tumors, those that begin in the heart, affect fewer than 1 in 2,000 people. [4] Heart tumors of all types are rare.
Is cardiac rhabdomyoma the most common fetal heart tumor?
Yes. Among heart tumors found in developing fetuses and children, cardiac rhabdomyoma is the most common type. [4]
Where in the heart do cardiac rhabdomyomas form?
Cardiac rhabdomyomas most often form in the right ventricle or left ventricle, the lower chambers of the heart. They can also appear in the atria (upper chambers) or in the septum, the wall between the ventricles. [4]
What do cardiac rhabdomyomas look like?
Cardiac rhabdomyomas appear as yellow or white nodules when viewed directly, and they typically form in clusters rather than as a single mass. [4]
How big do cardiac rhabdomyomas get?
Cardiac rhabdomyomas vary from just a few millimeters to several centimeters in size. [4]
How is cardiac rhabdomyoma different from a fibroma?
Both are benign heart muscle tumors, but rhabdomyomas typically appear in clusters of multiple nodules, while fibromas appear as a single tumor. [4]
What are the symptoms of cardiac rhabdomyoma?
Most cases have no symptoms. Rarely, larger tumors can cause rhythm changes, fast heart rate, breathing difficulty, chest pain, dizziness, fainting, fatigue, or swelling. [4]
Can cardiac rhabdomyoma cause heart failure or arrhythmia?
Rarely, yes. Tumors that grow or fail to resolve in babies and children can lead to heart failure or disrupt the heart's electrical system, which is why doctors monitor them closely. [2] [4]
Can a cardiac rhabdomyoma harm a fetus during pregnancy?
Yes, in some cases. A tumor that interferes with the fetal heart can cause heart failure or hydrops, a serious condition involving abnormal fluid buildup. [1] [4] Providers use imaging during pregnancy to check for these problems.
What is hydrops in a fetus?
Hydrops is a serious condition in which fluid accumulates abnormally in the developing fetus's body. [1] [4] A cardiac rhabdomyoma that disrupts the fetal heart can contribute to it.
When should I call 911 for a child with cardiac rhabdomyoma?
Call 911 for any change in heart rhythm, very fast heart rate, trouble breathing (especially when lying down), chest pain or tightness that improves when sitting up, coughing, dizziness or fainting, unusual fatigue or weakness, or swelling of the legs, ankles, or belly. [4]
How is cardiac rhabdomyoma diagnosed during pregnancy?
Cardiac rhabdomyoma is most often first identified on prenatal ultrasound, becoming visible between weeks 20 and 30 of pregnancy. [4] A fetal echocardiogram can also diagnose it. [1] [4]
What is a fetal echocardiogram?
A fetal echocardiogram is a specialized form of ultrasound that checks specifically for heart problems while the fetus develops in the uterus. [4]
How is cardiac rhabdomyoma diagnosed after birth?
After birth, diagnosis and evaluation rely on an electrocardiogram (EKG), an echocardiogram (echo), and magnetic resonance imaging (MRI). [4]
Why does my child need regular EKGs and echos?
Because the tumors usually shrink over time, regular tests confirm they are going away. [4] Tumors that do not resolve on their own will need treatment. [4]
Do cardiac rhabdomyomas need treatment?
Most do not. They usually go away on their own. [4] Treatment is reserved for the rare cases where tumors disrupt heart function during pregnancy or after birth. [4]
What happens if the tumor doesn't go away?
If a tumor does not resolve or continues to grow, it can disrupt heart function and lead to heart failure or arrhythmia, which may require medication. [4]
What medications treat cardiac rhabdomyoma?
Treatment may include ACE inhibitors, diuretics, and anti-arrhythmic medication. [4] Targeted medicines called mTOR inhibitors (everolimus or sirolimus) have also been used for benign heart tumors. [2] [3] During pregnancy, the mother may receive medication to shrink the tumor. [4]
Is surgery needed for cardiac rhabdomyoma?
What is watchful waiting for cardiac rhabdomyoma?
Watchful waiting means regular monitoring with imaging and heart tests to confirm the tumors are shrinking on their own, without active treatment.
Will a cardiac rhabdomyoma affect my child's long-term outlook?
Most children do not need treatment [4] and the tumors resolve, so the outlook is generally favorable. The presence of tuberous sclerosis determines the longer-term care plan.
Should I get genetic testing if my child has a cardiac rhabdomyoma?
If your child is diagnosed with tuberous sclerosis, genetic testing is recommended. Parents sometimes carry an undiagnosed mild form of the condition, so providers may test both parents for the mutation. [4]
What questions should I ask my child's doctor about cardiac rhabdomyoma?
Helpful questions include how the tumor will be monitored, whether medicine or surgery is likely, whether the child has tuberous sclerosis, how tuberous sclerosis would affect the child, whether a parent should have genetic testing, and whether the provider can connect the family with a support group. [4]
Related Reading
Tuberous Sclerosis: Symptoms, Causes, Diagnosis and Treatment — What You Need to Know
Congenital Heart Disease (CHD): Types, Causes, Symptoms, and Survival Outlook
Heart Arrhythmia: Symptoms, Types, Causes, Diagnosis & Treatment — Complete Guide
Congestive Heart Failure: Symptoms, Stages, and How It's Treated
References
Bejiqi R, Retkoceri R, Bejiqi H. Prenatally diagnosis and outcome of fetuses with cardiac rhabdomyoma - single centre experience. Open Access Maced J Med Sci. 2017;5(2):193-196. PMID: 28507627. https://doi.org/10.3889/oamjms.2017.040
Sugalska M, Tomik A, Jóźwiak S, Werner B. Treatment of cardiac rhabdomyomas with mTOR inhibitors in children with tuberous sclerosis complex: a systematic review. Int J Environ Res Public Health. 2021;18(9):4907. PMID: 34062963. https://doi.org/10.3390/ijerph18094907
PDQ Pediatric Treatment Editorial Board. Childhood heart tumors (PDQ) – patient version. National Cancer Institute. Updated October 4, 2024. https://www.cancer.gov/types/cardiac/patient-child-cardiac-treatment-pdq
Cleveland Clinic. Cardiac rhabdomyoma. Cleveland Clinic Health Library. Last updated March 17, 2022. https://my.clevelandclinic.org/health/diseases/22499-cardiac-rhabdomyoma
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition, especially concerning pregnancy, infants, or children. Never disregard professional medical advice or delay seeking it because of something you have read here.
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