What are noncancerous liver tumors?
Noncancerous (benign) tumors are quite common and usually do not produce symptoms. Often, they are not diagnosed until an ultrasound, computed tomography (CT) scan or magnetic resonance imaging (MRI) scan is performed. There are several types of benign liver tumors, including the following:
- Hepatocellular adenoma – this benign tumor occurs most often in women of childbearing age. Most of these tumors remain undetected. Sometimes, an adenoma will rupture and bleed into the abdominal cavity, requiring surgery. Adenomas rarely become cancerous.
- Hemangioma – this type of benign tumor is a mass of abnormal blood vessels. Up to 5 percent of adults have small liver hemangiomas that cause no symptoms. Treatment is usually not required. Sometimes, infants with large liver hemangiomas require surgery to prevent clotting and heart failure.
What are cancerous liver tumors?
Cancerous (malignant) tumors in the liver have either originated in the liver (primary liver cancer) or spread from cancer sites elsewhere in the body (metastatic liver cancer). Most cancerous tumors in the liver are metastatic.
Anatomy of the liver
The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm, and on top of the stomach, right kidney and intestines. Shaped like a cone, the liver is a dark reddish-brown organ that weighs about 3 pounds.
There are two distinct vessels that supply blood to the liver, including:
- Oxygenated blood flows in from the hepatic artery.
- Nutrient-rich blood flows in from the hepatic portal vein.
The liver holds about one pint (13 percent) of the body’s blood supply at any given moment. The liver consists of two main lobes, both of which are made up of thousands of lobules. These lobules are connected to small ducts that connect with larger ducts to ultimately form the hepatic duct. The hepatic duct transports the bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine).
Functions of the liver
The liver regulates most chemical levels in the blood and excretes a product called bile, which helps carry away waste products from the liver. All the blood leaving the stomach and intestines passes through the liver. The liver processes this blood and breaks down the nutrients and drugs into forms that are easier to use for the rest of the body. More than 500 vital functions have been identified with the liver. Some of the more well-known functions include:
- The production of bile, which helps carry away waste and break down fats in the small intestine during digestion.
- The production of certain proteins for blood plasma.
- The production of cholesterol and special proteins to help carry fats through the body.
- The conversion of excess glucose into glycogen for storage (glycogen can later be converted back to glucose for energy).
- The regulation of blood levels of amino acids, which form the building blocks of proteins.
- The processing of hemoglobin for use of its iron content (the liver stores iron).
- The conversion of poisonous ammonia to urea (urea is an end product of protein metabolism and is excreted in the urine).
- The clearing of drugs and other poisonous substances from the blood.
- The regulation of blood clotting.
- The production of immune factors and removal of bacteria from the bloodstream to help resist infections.
When the liver has broken down harmful substances, its byproducts are excreted into the bile or blood. Bile byproducts enter the intestine and ultimately leave the body in the form of feces. Blood byproducts are filtered out by the kidneys and leave the body in the form of urine.
Did you know?
The liver can lose three-quarters of its cells before it stops functioning. In addition, the liver is the only organ in the body that can regenerate itself.