Focal nodular hyperplasia (FNH) is a noncancerous liver lesion made of normal liver cells. It’s often found during imaging for another reason and rarely causes symptoms. Most people don’t need treatment. The outlook is excellent once the diagnosis is clear.
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Focal nodular hyperplasia (FNH) is a benign (noncancerous) liver tumor. These lesions are made up of normal liver cells that grow in an abnormal pattern around a central scar. FHN lesions typically don’t cause any symptoms. They’re often found by chance during imaging done for another reason.
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FNH lesions (growths) don’t spread and won’t damage your liver. They also don’t lead to cancer. They’re the second most common type of benign liver growth after hemangiomas. Most people have one lesion, but some may have more than one. FNH most commonly affects females.
Your healthcare provider will usually leave the lesion alone. If you have symptoms like pain or discomfort, FNH is rarely the cause. Once your provider has ruled out other causes, surgery to remove the FNH lesion could be an option.
Most people with FNH don’t have symptoms and never know they have it. Symptoms are more likely if the growth is larger or presses on nearby structures.
When symptoms do occur, they’re usually mild and may include:
The exact cause of FNH is unknown. Researchers think it might form as a response to unusual blood flow within your liver.
In many cases, an abnormal artery changes how blood flows through part of your liver. This causes the liver cells in that area to grow faster than the surrounding liver tissue, forming a focal nodular hyperplasia lesion.
FNH is a regenerative process. That means it forms when normal, healthy liver cells grow in response to changes in blood flow. It doesn’t occur because of uncontrolled or cancerous cell growth. The cells aren’t dangerous, and it’s not a precancerous lesion.
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FNH can occur in anyone, but it’s more common in females. It’s also more likely to affect people:
Although FNH is more common in females, estrogen, pregnancy and birth control pills haven’t been shown to cause it.
Complications are uncommon. Rarely, very large lesions may cause ongoing pain or pressure on nearby organs. Tumors can bleed or rupture, but it’s extremely rare.
Healthcare providers usually diagnose FNH with advanced imaging tests. On these tests, your provider will look for features that are typical of the condition, especially:
Accurate imaging is important because it helps tell FNH apart from cancerous tumors like hepatic adenomas and hepatocellular carcinoma (liver cancer).
Common tests include:
Blood tests are typically normal, and you probably won’t need a liver biopsy. Your provider will only consider a biopsy if the imaging results aren’t clear.
FNH usually requires no treatment. That’s because it isn’t cancerous and rarely causes symptoms. Your healthcare provider will likely just want to keep an eye on it. They may have you come in for follow-up scans every 12 months.
Your provider may consider treatment if the lesion is large and causing pressure or you have other ongoing symptoms. They’ll also recommend treatment if the diagnosis remains uncertain after imaging.
FNH treatment options may include:
Contact your provider if you:
FNH has an excellent prognosis (outlook). Most lesions stay the same size or may even shrink over time. The condition doesn’t affect your liver function. It also doesn’t carry any potential to become cancerous and doesn’t shorten your life expectancy. Many people never need follow-up care once the diagnosis is clear.
Learning you have a liver growth can feel unsettling. The important thing to know is that focal nodular hyperplasia is benign and doesn’t harm your liver. Many people never have symptoms or need treatment. With the right imaging and follow-up, your healthcare provider can be confident in the diagnosis and help you decide what — if anything — needs to happen next.
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Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
If you have a disease that’s affecting your liver, you want expert advice and care. At Cleveland Clinic, we’ll create a treatment plan that’s right for you.
