Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

LiverThe liver is the largest internal organ of the body, weighing three to four pounds (1.4-1.8 kg.).It lies immediately under the diaphragm in the right upper abdomen. Its visceral surface is moldedover the stomach, duodenum, gallbladder, hepatic flexure of the colon, right kidney, and rightsuprarenal gland. It is divided into right and left lobes. The right lobe has three parts called the rightlobe proper, the caudate lobe, and the quadrate lobe. The small bile ducts within the liver(intrahepatic ducts) join to form two larger ducts which emerge from the under surface of the liverat the porta hepatis as the right and left hepatic ducts.The liver is one of the most vital organs in the body and plays a crucial role in the digestion andabsorption of food. It breaks down protein, stores glycogen, iron, and vitamins, maintains thecomposition of the blood, and secretes products of detoxification. It continuously produces bile whichis important in the digestion of fat and protein. The liver assists in keeping the amount of glucose(sugar) in the blood at a normal level. The liver manufactures plasma proteins. It destroys worn-outerythrocytes and foreign materials (phagocytosis). It produces heparin, an anticoagulant. It removesnitrogen from amino acids and converts it into urea. The urea then enters the blood stream and iscarried to the kidneys where it is concentrated in urine and eliminated from the body.The liver secretes certain bile salts which aid in digestion. These substances pass through the bileducts and may be stored in the gallbladder. With the stimulation of eating, these chemicals then passthrough the cystic duct and the common bile duct to enter the duodenum at the ampulla of Vater.All of these ducts and the gallbladder are referred to as the "extra-hepatic biliary system."The lymphatic drainage from the liver is to hilar nodes, hepatic and periportal nodes below thediaphragm, and to cardiac, pericardial, posterior mediastinai, and aortic nodes above the diaphragm.Lymphatic vessels reach all parts of the organ.Malignant and Benign TumorsMalignant tumors of the liver are of glandular origin, i.e., adenocarcinomas. Benign liver tumorsare of current interest because of a suggested association with oral contraceptive use. Primary livertumors are rare, but may be classified as follows:• Hepatocellular carcinoma (hepatoma, liver cell carcinoma) arises in the parenchymal cells ofthe liver. It is the predominant type of primary malignant liver tumor and is associated withpre-existing cirrhosis of the liver.• Cholangiocarcinoma (bile duct carcinoma) arises in the intrahepatic bile ducts. Consequently,you may find cholangiocarcinomas of the liver as well as of the extrahepatic bile ducts.• Hemangioma is a benign tumor which arises in the blood vessels of the liver; it is the mostcommon benign liver tumor.• Adenomas may arise in either the liver cells or the bile ducts of the liver.229