Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.

Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.

Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth, nodule, or tumor.

Growths in the liver can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors:

• Benign tumors:
  • are rarely a threat to life
  • can be removed and usually don't grow back
  • don't invade the tissues around them
  • don't spread to other parts of the body
  
  
• Malignant growths:
  • may be a threat to life
  • sometimes can be removed but can grow back
  • can invade and damage nearby tissues and organs (such as the stomach or intestine)
  • can spread to other parts of the body

Most primary liver cancers begin in hepatocytes (liver cells). This type of cancer is called hepatocellular carcinoma or malignant hepatoma.

Liver cancer cells can spread by breaking away from the original tumor. They mainly spread by entering blood vessels, but liver cancer cells can also be found in lymph nodes. The cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues. See the Staging ¹ section for information about liver cancer that has spread.

Glossary Terms

Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called nonmalignant.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A type of adenocarcinoma, the most common type of liver tumor.

A liver cell.

A liver tumor.

The long, tube-shaped organ in the abdomen that completes the process of digestion. The intestine has two parts, the small intestine and the large intestine. Also called bowel.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

A growth or lump that may be malignant (cancer) or benign (not cancer).

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.