Cardiac rhabdomyomas are benign tumors that form in the heart muscle. They’re rare overall, but they’re the most common type of heart tumor in babies and children. Rhabdomyomas are diagnosed by fetal ultrasound or through cardiac imaging after birth. Rhabdomyomas often signal the presence of a rare genetic disorder called tuberous sclerosis.
A cardiac rhabdomyoma is a noncancerous (benign) tumor in your heart muscle. Cardiac rhabdomyomas are rare. But they’re the most common type of fetal cardiac tumor. A cardiac rhabdomyoma often appears during gestation (in the uterus) or within one year of birth.
Cardiac rhabdomyomas grow directly from the heart muscle. They typically appear in clusters. This sets them apart from another type of benign tumor called fibromas. Fibromas also form in the heart muscle but only appear as a single tumor, not as a cluster.
Cardiac rhabdomyomas aren’t malignant or cancerous. They don’t spread. They only become dangerous if they disrupt the normal functioning of your child’s heart. But this is rare. Usually, cardiac rhabdomyomas go away on their own and don’t cause serious problems.
Cardiac rhabdomyomas can appear on either side of your child’s heart (right or left). They’re usually in the right ventricle or left ventricle (lower chambers of the heart). Sometimes, they appear in the atria (upper chambers) or the wall that separates the ventricles. The tumors can vary in size from just a few millimeters to several centimeters. They look yellow or white when seen with the naked eye.
Cardiac rhabdomyomas are benign tumors that usually appear in clusters in your heart muscle.
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Babies and children who have tuberous sclerosis are more likely to have cardiac rhabdomyomas. At least 8 out of 10 people with cardiac rhabdomyomas also have tuberous sclerosis. Tuberous sclerosis is a rare genetic disorder that affects 1 in 6,000 newborns in the U.S.
Research shows no differences based on sex, ethnicity or race.
Cardiac rhabdomyomas are the most common type of heart tumor in unborn babies and children. But cardiac rhabdomyomas are still rare because heart tumors are rare. Tumors that begin in the heart (called primary cardiac tumors) affect fewer than 1 in 2,000 people.
Cardiac rhabdomyomas are likely caused by genetic changes that happen before birth. These changes lead to tuberous sclerosis. People with tuberous sclerosis have mutations in their TSC1 or TSC2 gene. The TSC1 and TSC2 genes are responsible for suppressing tumors. Most children with cardiac rhabdomyomas have tuberous sclerosis.
Some children don’t have tuberous sclerosis, but they develop a cardiac rhabdomyoma. In those cases, the cause of the tumor is unknown.
A cardiac rhabdomyoma is usually present at birth. So, it’s considered congenital. But that’s not the same thing as hereditary. If a condition is hereditary, it can be passed down through a family’s genes.
Cardiac rhabdomyomas can be hereditary, but they’re often not. That’s because the genetic disorder associated with the tumors (tuberous sclerosis) often has no hereditary link.
A parent with tuberous sclerosis has a 50% chance of passing it on to their child. But this “inheritance” only explains 1 in 3 cases of tuberous sclerosis. The rest of the cases arise on their own with no family history. The genetic mutation appears for the first time in the newly diagnosed baby. So, that means cardiac rhabdomyomas can appear predictably or out of the blue.
It’s a lot to take in and sometimes feels like a numbers game. But remember that genes are only part of the story. If you have concerns about cardiac rhabdomyomas or tuberous sclerosis, talk with your provider. Discuss your family history and how it might affect you or your child.
A cardiac rhabdomyoma usually has no symptoms. But rarely, a tumor or cluster of tumors can cause problems within your child’s heart that lead to symptoms. For example, larger tumors may block blood flow or disrupt heart rhythm. If this happens during pregnancy, it can be very harmful to the fetus. It may lead to heart failure or a serious condition called hydrops.
Your healthcare provider will run imaging tests during pregnancy to check for any signs or symptoms of these problems.
Tumors that grow or don’t go away in babies and children can lead to heart failure or arrhythmia. This is rare. But your child’s doctor will keep an eye on the situation to identify any problems.
Call 911 if you notice any of these symptoms in your child:
A cardiac rhabdomyoma is diagnosed through imaging tests. These tests can take place during pregnancy or after birth.
The tumor is often first identified through prenatal ultrasound. The tumor becomes visible on the ultrasound between weeks 20 and 30 of pregnancy. It may also be diagnosed through a fetal echocardiogram. This is a form of ultrasound that checks specifically for heart problems before a baby is born.
Tests that diagnose and evaluate a cardiac rhabdomyoma after a baby is born include:
Your child may need some tests like an EKG and echo regularly. Your provider will check on the tumors and make sure they’re going away. Tumors that don’t go away on their own will need treatment.
A cardiac rhabdomyoma is often the first sign of tuberous sclerosis. Your child may need further testing to check other parts of their body for signs of tuberous sclerosis.
If your child is diagnosed with tuberous sclerosis, talk with your provider about genetic testing. Sometimes parents have a mild form of the condition but were never diagnosed. So, your provider may want to see if you or your partner have the genetic mutation that causes the condition.
Cardiac rhabdomyomas usually go away on their own and don’t need treatment. Most of the time, the tumors reach their largest size when a baby is born. After that point, the tumors get smaller on their own and don’t cause any problems.
Rarely, cardiac rhabdomyomas need treatment because they disrupt heart function. Sometimes this happens during pregnancy. In this case, the birthing parent may need to take medication that makes the tumor smaller.
Sometimes problems happen after birth. If the tumor or cluster of tumors hasn’t gone away or grows in size, it can disrupt your child’s heart function. This can lead to heart failure or arrhythmia.
If this happens, your child may need medications including:
Your provider will discuss treatment options with you and help you choose the best plan for your child. Surgery is rarely needed.
Most people with cardiac rhabdomyoma don’t need treatment. But the presence of other medical conditions like tuberous sclerosis affects their outlook.
If your child has tuberous sclerosis, they’ll need regular medical checkups and tests. This condition is mild and not even noticeable for some people. But it can cause serious complications and severely impact quality of life for other people. Your provider will talk with you about your child’s specific medical needs and prognosis. Together, you’ll develop the best possible care plan for your child.
Talk with your provider about your child’s condition and prognosis. If you’re pregnant and just received a fetal cardiac rhabdomyoma diagnosis, you might not know where to start. Your provider will answer many of your questions before you even know what to ask. But here are some general questions that can be helpful to ask as you learn more:
A note from Cleveland Clinic
When your child is diagnosed with a medical problem, it can be scarier than being diagnosed yourself. But with the right resources, you can stay on top of the problem and help your child get healthy. If your child has cardiac rhabdomyomas, talk with their provider to learn more. Your child’s provider may recommend “watchful waiting” to keep an eye on the tumors and see if they go away. Usually, this approach is all that you need. But your provider will let you know if treatments are necessary.
Last reviewed by a Cleveland Clinic medical professional on 03/17/2022.
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