When a cancerous tumor develops in the liver, it is called a primary tumor. If the tumor cells break off and forms elsewhere in the body it is called secondary tumor. For example, if liver cancer cells breaks off and spreads to the intestines, it is treated as metastatic liver cancer, not as intestinal cancer.
Hepatocellular carcinoma (HCC) is the most common form (about 75 percent) of liver cancer in adults, according to the American Cancer Society (ACS).
Some HCC starts as a single tumor that grows larger and can spread to other parts of the liver in the later stages. In the U.S. cirrhosis is the most commonly seen cell growth pattern of this type.
Another type of liver cancer, called bile duct cancer or cholanglocarcinoma, accounts for 10-20 percent of all liver cancers. It originates in the bile ducts that feed the gallbladder.