Liver cancer is a cancer that starts in the liver. To understand liver cancer, it helps to know about how the normal liver looks and works.

The liver is the largest organ inside the body. It lies under your right ribs, just below the right lung. If you were to poke your fingers up under your right ribs, you would almost touch your liver.

The liver is shaped like a pyramid and is divided into right and left lobes. Unlike most other organs, the liver gets blood from 2 sources. The hepatic artery supplies the liver with blood that is rich in oxygen. The portal vein carries nutrient-rich blood from the intestines to the liver.

The liver has many vital functions you cannot live without:

• It breaks down and stores many of the nutrients absorbed from the intestine.
• It makes some of the clotting factors needed to stop bleeding from a cut or injury.
• It secretes bile into the intestine to help absorb nutrients.
• It plays an important part in removing toxic wastes from the body.

Because the liver is made up of different types of cells, many types of tumors can form in the liver. Some of these are cancer and some are not. Tumors that are cancer are called malignant. The medical word for tumors that are not cancer is benign. These tumors have different causes and are treated different ways. The outlook for your health or recovery (prognosis) depends on what type of tumor you have.

Benign tumors

Benign tumors can sometimes grow large enough to cause problems. But most of the time they do not go into nearby tissues or spread to distant parts of the body. If they need to be treated, they can usually be cured by removing them with surgery. Below are the different kinds of benign liver tumors.

Hemangiomas: These are the most common type of benign liver tumor. They start in blood vessels. Because most of these tumors do not cause symptoms, they do not need treatment. But some may bleed and need to be removed.

Hepatic adenomas: These are benign tumors that start from the main type of liver cells (hepatocytes). Most do not cause symptoms and do not need treatment. But if they cause stomach pain, a mass in the belly (abdomen), or blood loss, they may need to be removed.

Women have a higher chance of having one of these tumors if they take birth control pills, but this is rare. Stopping the pills can cause the tumor to shrink. Men who use anabolic steroids may also develop these. They may shrink when the drugs are stopped.

Focal nodular hyperplasia: Focal nodular hyperplasia, or FNH, is a tumor-like growth of several cell types. Although FNH tumors are benign, it can sometimes be hard to tell them apart from true liver cancers. If there are symptoms, the tumor can be removed.

Cancers that start in the liver

Several types of cancer can start in the liver.

Hepatocellular carcinoma (HCC): This is the most common form of liver cancer in adults. It begins in the hepatocytes, the main type of liver cell. About 3 out of 4 cancers that start in the liver are this type. Most of the information in this article refers to hepatocellular cancer.

This type of cancer can have different growth patterns.

• Some begin as a single tumor that grows larger. Only late in the disease does it spread to other parts of the liver.

• This type of cancer may also begin in many spots throughout the liver, not as a single tumor. This is most often seen in people with cirrhosis and is the most common pattern seen in the United States.

Doctors can figure out the subtypes of hepatocellular cancer by looking at the cancer under a microscope. Most of these subtypes do not affect treatment or the patient's outlook. But one rare type, called fibrolamellar, has a much better outlook (prognosis) than other forms of liver cancer.

Cholangiocarcinomas (bile duct cancers): Cholangiocarcinomas account for 1 or 2 out of every 10 cases of liver cancer. These cancers start in the small tubes (called bile ducts) that carry bile to the gallbladder. Although the rest of the information here covers mainly hepatocellular cancers, cholangiocarcinomas are often treated the same way. For more information on this type of cancer, please see our document Bile Duct Cancer.

Angiosarcomas and hemangiosarcomas: These are rare forms of cancer that start in the blood vessels of the liver. These tumors grow quickly. Often by the time they are found they are too widespread to be removed. Treatment may help slow the disease, but most patients do not live more than a year after these cancers are found.

Hepatoblastoma: There is a very rare kind of liver cancer that develops in children. It is usually found in children younger than 4 years old. About 70% of children with this disease are treated successfully with surgery and chemotherapy. The survival rate is greater than 90% for early-stage disease.

Secondary liver cancer

Most of the time when cancer is found in the liver it did not start there, but started somewhere else and spread to the liver. This is called metastatic cancer. This can happen to people with advanced breast cancer, colorectal cancer, lung cancer, and many other cancers, too. Under a microscope, theses cancer cells in the liver look like the cancer cells that they came from. If someone has lung cancer that has spread to the liver, the cells there will look and act like lung cancer cells and they will be treated the same way.

To learn more about metastatic liver cancer, please see our document Advanced Cancer, as well as the document on the specific place where the cancer started (Breast Cancer, Lung Cancer, Colorectal Cancer, etc.).

The rest of the information given here covers only primary liver cancer, that is, hepatocellular cancer, or cancer that starts in the liver.

Last Medical Review: 01/09/2009
Last Revised: 05/06/2009