Liver lesions are abnormal growths on your liver. Most are noncancerous, or benign. Benign liver lesions don’t cause symptoms or require treatment unless they grow very large.

Liver lesions are found in as many as 30 percent of people over the age of 40.

The majority of liver lesions are noncancerous, or benign. Many lesions are detected during imaging tests for unrelated health conditions. Although most lesions aren’t harmful, it’s still critical to receive a proper diagnosis.

Keep reading to learn more about how liver lesions are classified, what causes them, and when treatment is needed.

Liver lesions are any abnormal growths on your liver. They’re divided into two categories: malignant and benign.

Malignant lesions are cancerous. They require treatment to keep them from spreading. Benign lesions are noncancerous. Some benign tumors require treatment while others don’t.

Malignant lesions

Types of cancerous lesions include:

Type of cancerNotes
hepatocellular carcinomamost common form of adult liver cancer
third leading cause of cancer death worldwide
– develops in the body of your liver
intrahepatic cholangiocarcinoma– develops in the bile ducts that connect your liver to your gallbladder
– responsible for 10 to 20 percent of liver cancers
angiosarcoma and hemangiosarcoma– rare cancers of the cells that line your liver’s blood vessels
hepatoblastoma– a very rare cancer that develops in children under the age of 4
liver metastasis– “metastasis” means the cancer has spread from another organ where the cancer started; in this case, it spreads to the liver
most liver lesions in the United States and Europe are metastasized from other areas where the cancer started

Benign lesions

Benign lesions are noncancerous growths. Small benign lesions often don’t cause symptoms and don’t require treatment. If tumors grow large, they may cause symptoms and need to be removed.

The following lesions may require treatment:

Benign lesions that may require treatmentNotes
hepatocellular adenoma– may need treatment if the lesion is more than 5 centimeters (cm) wide or causing symptoms
hepatic cysts– treatment may be needed if cysts cause symptoms or they’re more than 4 cm across

The following types of lesions usually don’t require treatment:

Benign lesions that don’t need treatmentNotes
hepatocellular adenoma– solid noncancerous lesions on an otherwise healthy liver
– treatment often not needed if the lesion is less than 5 cm wide and not causing symptoms
hepatic cysts– fluid-filled sacs on your liver
– no treatment is needed if cyst is small and not causing symptoms
hepatic or cavernous hemangioma– clusters of blood vessels that create tumors on your liver
– rarely needs treatment unless they grow very large
focal nodular hyperplasia– caused by an increase in the number of functional cells
– thought to be caused by malformations in the arteries

Liver lesions are common, but it’s not always clear why they develop.

Malignant lesions

Like all cancers, cancerous lesions of the liver are caused by changes to the DNA that make cells replicate uncontrollably.

A primary risk factor of malignant liver lesions (hepatocellular carcinoma) is long-term hepatitis B or hepatitis C infection.

Additional possible causes of liver lesions include:

  • long-term use of birth control pills
  • long-term use of anabolic steroids
  • liver scarring (cirrhosis)
  • smoking

Benign lesions

The cause of benign lesions can vary depending on the type of lesion:

  • Hepatic adenomas. Long-term use of birth control pills or anabolic steroids may cause these lesions.
  • Cavernous hemangiomas. These lesions are usually present at birth and develop from genetic mutations.
  • Focal nodular hyperplasia. The malformation of arteries in the liver can cause these.
  • Liver cysts. Although the cause is usually unknown, some cysts may be present from birth. Others may develop from an echinococcus infection.

Anybody can develop liver lesions, but some people are at a higher risk than others. The top risk factor for liver cancer is chronic viral hepatitis.

Other liver cancer risk factors include:

Benign liver lesions

Risk factors for benign lesions include:

  • ongoing use of birth control pills or anabolic steroids
  • being of childbearing age in people assigned female at birth

Liver lesions are often discovered through imaging tests.

According to the American Cancer Society, liver cancer often doesn’t cause symptoms until the late stages. As a tumor grows larger, it can cause liver dysfunction or problems by pushing on other tissues.

When symptoms do appear, they most commonly include:

Benign tumors usually don’t cause symptoms unless they grow very large.

Doctors start the process of diagnosing liver lesions by taking your medical history, considering your symptoms, and performing a physical examination. Next, they may order a combination of blood tests and imaging.

Imaging techniques include:

Blood tests can identify viral hepatitis infection or markers that identify liver disease.

Most lesions can be diagnosed without the need for a tissue sample called a biopsy. However, a biopsy may be needed in difficult cases.

Some benign lesions don’t require any treatment if they’re not causing symptoms. Larger lesions causing symptoms may need to be surgically removed.

Treatment for liver cancer depends on factors such as:

  • your general health
  • how far it has spread
  • tumor size and location
  • the type of cancer

Treatment options include:

  • surgery to remove the lesions and part or all of your liver
  • liver transplant if your entire liver is removed
  • a form of chemotherapy called chemoembolization to stop the cancer from growing
  • thermal ablation, which uses high energy electric current or microwaves to destroy cancer cells not able to be removed with surgery
  • targeted medications to stop cancer cells from growing
  • a type of radiation therapy called internal radiation therapy where radioactive beads are injected into the blood vessels of your liver

The 5-year survival rate of liver cancer continues to rise in the United States. It’s increased from 3 percent to over 20 percent in the past 40 years, according to the American Society of Clinical Oncology.

The most common risk factor worldwide for liver cancer is chronic hepatitis B or hepatitis C infection. Getting the hepatitis B vaccine and proper treatment for viral hepatitis can lower your risk of liver cancer.

Other ways you may be able to lower your risk of developing liver lesions include:

  • limiting tobacco and alcohol use
  • maintaining a moderate weight
  • getting treatment for conditions that can cause liver cancer, such as hemochromatosis
  • eating a balanced diet to minimize the risk of developing type 2 diabetes
  • avoiding recreational anabolic steroids (these are different than steroid injections used to treat health conditions)
  • avoiding behaviors that can increase your chances of contracting hepatitis, such as injected drug use and sex without a barrier method, like a condom

Liver lesions are common. They can be cancerous or noncancerous. Most lesions are noncancerous and don’t require treatment if they’re small and don’t cause symptoms.

Your doctor can diagnose liver lesions with a combination of imaging, blood tests, and sometimes a small tissue sample. They can advise you about whether any particular treatment is needed.