The liver can be affected by primary liver cancer, which arises in the liver, or by cancer which forms in other parts of the body and then spreads to the liver. Most liver cancer is secondary or metastatic, meaning it started elsewhere in the body.
Because the liver is made up of several different types of cells, several types of tumors can form there. Some of these are benign (noncancerous), and some are cancerous and can spread to other parts of the body (metastasize). These tumors have different causes and are treated differently.