Causes

Your liver is a football-sized organ that sits in the upper right portion of your abdomen, beneath your diaphragm and above your stomach. Your liver processes most of the nutrients absorbed from your small intestine and determines how much sugar (glucose), protein and fat enter your bloodstream. It also manufactures blood-clotting substances and certain proteins. Your liver performs a vital detoxifying function by removing drugs, alcohol and other harmful substances from your bloodstream.

Liver cancer occurs when liver cells begin to grow abnormally. It's not completely understood why this happens, but researchers believe that cancer starts with damage to DNA — the material that contains the instructions for every chemical process in your body, including the rate of cellular growth. DNA damage causes changes in these instructions. One result is that cells may begin to grow out of control and eventually form a tumor — a mass of malignant cells.

Primary liver cancer
Primary liver cancer is divided into several types based on the type of cells that become cancerous. Types include:

* Hepatocellular carcinoma (HCC). This is the most common form of primary liver cancer in both children and adults. It starts in the hepatocytes, the main type of liver cell.
* Cholangiocarcinoma. This type of cancer begins in the small tube-like bile ducts within the liver. This type of cancer is sometimes called bile duct cancer.
* Hepatoblastoma. This rare type of liver cancer affects children younger than 4 years of age. Most children with hepatoblastoma can be successfully treated.
* Angiosarcoma or hemangiosarcoma. These rare cancers begin in the blood vessels of the liver and grow very quickly.