Focal nodular hyperplasia is a benign tumor, or lesion, that forms in the liver. These tumors are not cancerous. The condition is more common in women, mostly between the ages of 20 and 50. It's the second most common type of benign liver tumor, after liver hemangiomas.
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What Is Focal Nodular Hyperplasia?
Focal nodular hyperplasia (FNH) is a mass or growth unique to the liver. Because the liver is the only self-regenerative organ of the body, it is at risk of developing atypical growths. Unlike the most common tumor of the liver, hemangioma, FNH tumors are largely solid, benign masses that do not draw blood flow.
How common is focal nodular hyperplasia?
FNH affects between 0.6% and 3% of the general U.S. population. About 8% of all benign liver tumors that aren't hemangiomas are FNH.
What causes focal nodular hyperplasia?
The direct cause of FNH is not yet understood, but the leading theory is believed to be malformations of the arteries of the liver. It is also believed that estrogen may play a role in the growth of these tumors, as well.
Focal nodular hyperplasia risk factors
FNH doesn't become cancerous. Most people with the disease don't have any problems, and the tumors often don't change much over time. Sometimes, the lesions get bigger, especially in women who are pregnant or who take birth control pills.
If you have a liver hemangioma, you might be at increased risk for FNH.
Researchers are also looking into whether gene changes or mutations play a role in FNH.
Complications of focal nodular hyperplasia
While these tumors are benign, their presence in the liver can complicate liver function by creating increased pressure on the liver and its blood vessels. Increased pressure is commonly only an issue for tumors that grow beyond the typical size of 4 to 8 centimeters. In rare cases, tumors can rupture.
What Are the Signs and Symptoms of Focal Nodular Hyperplasia?
Most people with FNH don't have any symptoms. These tumors are most often between 4 and 8 centimeters in size.
Rarely, some people with FNH feel a lump or pain in the stomach.
When should I see a doctor about my focal nodular hyperplasia symptoms?
Often, these tumors are caught while scanning for other conditions or during routine exams. If you are experiencing pain in your side or stomach, you should inform your primary care physician if the pain persists for more than two weeks. Otherwise, FNH may not show any noticeable symptoms, so be sure to see your doctor for regular screenings.
How Do You Diagnose Focal Nodular Hyperplasia?
FNH tumors have a special type of scar formed from different tissue types. This “central scar" tells doctors that the tumor is FNH and not hepatocellular carcinoma, a type of cancer. Often, doctors find FNH during imaging scans for other conditions.
Tests your doctor may order include:
- Imaging scans – Doctors use CT or MRI scans to get clear images of your liver to identify the formation of masses.
- Liver biopsy – Doctors take a small sample of liver tissue and send it to the lab to look at under a microscope.
Focal nodular hyperplasia prognosis
FNH growths are benign and can sometimes be resolved with lifestyle changes. The outlook for this condition is very good and rarely results in life-threatening complications. Many people’s tumors remain the same size and do not have additional problems.
How Do You Treat Focal Nodular Hyperplasia?
As these tumors are benign, there may not be an immediate need to remove them. Treatment options range from lifestyle changes and minimally invasive treatments to surgical removal. Your doctor will help guide you through the best options based on your case of FNH.
Lifestyle changes
Your doctor might suggest you stop taking birth control pills if you have FNH. If you keep taking them, they might want you to have routine imaging tests to keep an eye on the tumor(s).
To support your liver's health, your doctor might also urge that you:
- Avoid alcohol.
- Eat a healthy diet.
- Exercise.
- Maintain a healthy weight.
Transarterial embolization (TACE)
If your tumor gets larger than the typical 4 to 8 cms, doctors may use the minimally invasive procedure called TACE to shrink it. During transarterial embolization, the specialist will inject medicine into the hepatic artery to block blood flow and prevent the mass from growing.
Surgery
If the FNH is large, surgeons may remove the tumor. In partial hepatectomy surgery, or resection, surgeons extract the tumor and a small part of the tissue around it.
How effective is treatment?
Treatment can be very effective in eliminating tumors or preventing their continued growth. If FNH tumors remain small enough, their presence may not create any issues for the liver.
