The liver is one of the most important organs in your body: It breaks down food into energy and rids your body of substances that could harm you. When cancer cells are growing inside the liver, it’s called liver cancer.

Types of Liver Cancer

Doctors classify liver cancers into two categories:

• Primary liver cancers are tumors that develop directly from liver tissue.
• Secondary, or metastatic, liver cancers are tumors that start in another part of the body, such as the colon, then spread to the liver.

The most common primary liver cancers include:

• Hepatocellular carcinoma: This cancer commonly (but not always) coincides with liver disease (or a cirrhotic liver) and is related to:
  • Chronic alcohol use
  • Chronic hepatitis
  • A diet high in fatty foods
• Gallbladder carcinoma: Found in gallbladder tissue, this cancer often causes no obvious symptoms until advanced stages.
• Cholangiocarcinoma: This cancer is found in the bile ducts, which are the tubes around and inside the liver.

Metastatic Liver Cancer

“In Western countries such as the United States, the most common tumors we find in the liver are metastatic cancers that started somewhere else,” says Weiss.

Several different types of tumors can spread to the liver. These include:

• Colorectal cancer, which grows in the intestine lining
• Sarcoma, which develops in the bones or connective tissue
• Adrenal tumors, which start in the adrenal glands (above your kidneys)
• Renal carcinoma, which develops in the kidney
• Neuroendocrine tumors, which grow from the body’s endocrine (hormonal) cells

Diagnosing Liver Cancer

Liver cancer is most commonly found on an imaging test, such as a CT or MRI scan, that someone receives for a completely separate reason. “This is because liver cancers don’t always present obvious symptoms in their early stages,” says Weiss. “Some people experience no symptoms of liver cancer when they’re diagnosed.”

Once doctors spot a liver mass, or lesion, they will likely recommend other diagnostic tests to figure out whether the mass is benign (noncancerous) or malignant (cancerous).