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

• 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 several different types of cells, many types of tumors can form in the liver. Some of these are cancerous and some are not cancerous. The medical word for tumors that are not cancer is benign (be-nine). These tumors have different causes and are treated different ways. The outlook for your health or recovery depends on what type of tumor you have.

Benign Tumors

Hemangiomas

Hemangiomas (he-man-gee-O-muhs) 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 by surgery.

Hepatic Adenomas

Hepatic adenomas (huh-pat-ic ad-uh-noh-muhs) 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 (“steroids”) may also develop these. They can also shrink when the drugs are stopped.

Focal Nodular Hyperplasia

Focal nodular hyperplasia (hy-per-play-zuh), 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.

Malignant Tumors That Start in the Liver

Below are some of the different kinds of cancerous tumors that start in the liver.

Hepatocellular Carcinoma

While there are other types of liver cancer, the most common form in adults is called hepatocellular carcinoma (huh-pat-uh-CELL-u-lar car-sin-o-muh). It begins in the hepatocytes, the main type of liver cell. About 3 out of 4 primary liver cancers 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 and not as a single tumor. This is most often seen in people with liver cirrhosis and is the most common pattern seen in the United States.

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

Cholangiocarcinomas

Cholangiocarcinomas (co-lan-gee-o-car-sin- O-muhs) account for 1 or 2 out of every 10 cases of liver cancer. These cancers start in the small tubes that carry bile to the gallbladder (called bile ducts). Although the rest of the information here covers hepatocellular cancers, cholangiocarcinomas are often treated the same way. For more information on this type of cancer, please see the ACS document, Bile Duct Cancer.

Angiosarcomas and Hemangiosarcomas

There are other rare forms of cancer that begin in the blood vessels of the liver called angiosarcomas (an-gee-o-sar-CO-muhs) and hemangiosarcomas (huh-man-gee-o-sar-CO-muhs). These tumors grow quickly. Often by the time they are found they are too widespread to be removed. Treatment may not help very much. Patients often live less than 6 months after these cancers are found.
 
Hepatoblastoma

There is a very rare kind of liver cancer that develops in children. It is called hepatoblastoma (huh-pat-o-blas-to-muh). 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 spread to the liver from a cancer that began somewhere else in the body. These tumors are named after the place where they began (the primary site) and are further described as metastatic. For example, cancer that started in the lung and spread to the liver is called metastatic lung cancer to the liver. The rest of the information given here covers only primary liver cancer, that is, cancer that starts in the liver.