A tumor is an abnormal growth of cells or tissues. Some tumors are malignant, or cancerous. Others are benign, or noncancerous.
Cancerous liver tumors can be fatal. Most of the time, cancerous tumors in the liver started in another organ and spread to the liver. This form of liver cancer is called metastatic liver cancer. Cancerous liver tumors that start in the liver are relatively rare in the United States. This form of liver cancer is called primary liver cancer.
Noncancerous, or benign, liver tumors are common. They do not spread to other areas of the body, and they usually do not pose a serious health risk.