A liver hemangioma is a tangled network of blood vessels in or on the surface of the liver. This tumor is noncancerous and usually doesn’t cause symptoms.

Most people don’t even know they have a liver hemangioma. It’s usually only discovered during a test or procedure for an unrelated condition. Even when they’re diagnosed, most liver hemangiomas don’t require treatment.

A liver hemangioma doesn’t increase your risk of developing cancer. The tumor is usually small, measuring less than 4 centimeters in diameter. In some cases, however, it can grow much larger. A larger tumor is more likely to cause symptoms, such as abdominal pain and nausea.

Pregnant people and those using estrogen replacement therapy have a higher risk of developing a large hemangioma. This is because estrogen may contribute to the growth of liver hemangiomas.

Most people only have one liver hemangioma. However, it’s possible for several hemangiomas to form on the liver at once.

Although the tumor isn’t cancerous, it has been linked to higher rates of heart failure.

A liver hemangioma typically doesn’t cause complications in adults, but it can be more dangerous when it develops in infants. In babies, the growth is called infantile hepatic hemangioma. It’s usually diagnosed before the baby is 6 months old. This is a rare condition in infants.

In most cases, a liver hemangioma doesn’t cause symptoms. However, symptoms can occur if the tumor has been aggravated by an injury or affected by a change in estrogen levels.

Symptoms may include:

  • pain in the upper right side of the abdomen
  • nausea
  • vomiting
  • a lack of appetite

Even if you have a liver hemangioma, these symptoms may be caused by something else. Contact your doctor if you have any symptoms that worry you.

Doctors aren’t sure why blood vessels clump together and form a liver hemangioma. However, they do believe that it has a genetic component, which means it tends to run in families. Some liver hemangiomas may be present at birth.

People are at increased risk for a liver hemangioma if they have family members with liver hemangiomas. Those between the ages of 30 and 50 are also at a higher risk for a liver hemangioma.

Women are more likely than men to develop a liver hemangioma. Because estrogen is believed to fuel the growth of a hemangioma, the mass may be larger in women as well.

People who use hormone replacement therapy to increase their estrogen levels are also at an increased risk of developing a liver hemangioma.

A liver hemangioma usually doesn’t cause symptoms, so it often goes undiagnosed. It’s typically found incidentally during a test or procedure for another medical condition.

A liver hemangioma may be discovered during an imaging test, such as an ultrasound, CT scan, or MRI scan.

These are low-risk, noninvasive tests that create pictures of various organs and tissues inside the body. They make it possible for your doctor to see the liver and its surrounding structures in more detail.

If your doctor is looking for other liver abnormalities, they may find a hemangioma.

Most liver hemangiomas don’t require treatment, and only some need monitoring. However, a hemangioma may need to be removed surgically if it’s large and growing or causing symptoms.

If it causes significant pain or damage to a part of the liver, your doctor may decide to remove the entire affected section of the liver.

A liver hemangioma can grow if there’s a significant amount of blood flowing to it.

In this case, your doctor may tie off the main artery that’s supplying blood to the hemangioma. The areas surrounding the liver will get blood from other arteries and remain healthy. This surgical procedure is known as hepatic artery ligation.

In other cases, your doctor may decide to inject a medication into the hemangioma to block the blood supply, which leads to its eventual destruction. This is called arterial embolization.

In very rare situations, a liver transplant may be required. During this procedure, your damaged liver is replaced with a donor’s liver. This is only necessary if the hemangioma is extremely large or if multiple hemangiomas don’t respond to other treatments.

Radiation therapy may also be needed to shrink the mass. However, this is also an extremely rare form of treatment.

Liver hemangiomas rarely cause any complications. Complications that can arise in very rare cases include:

  • enlarged hemangioma
  • liver damage
  • severe pain

Talk to your doctor about how you can reduce your risk for these complications, especially if you’re pregnant, using hormone therapy, or have liver disease.

A liver hemangioma rarely causes future complications. However, a hemangioma may begin to cause problems if it increases in size.

Pay attention to any symptoms that could be related to an enlarged hemangioma, such as nausea, vomiting, and persistent pain in your upper right abdomen.

It’s also important to take care of your liver. Lifestyle changes, such as reducing alcohol intake, maintaining a moderate weight, and considering quitting smoking if you’re a smoker, can lower your risk of developing other, more serious liver conditions.