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Liver cancer is a cancer that starts in the liver.
Tounderstand liver cancer, it helps to know about the normal structure
and function of the liver.
About the liver
The liver is the largest internal organ. It lies under your
right ribs just beneath your right lung. If you were to poke your
fingers up under your right ribs, you could almost touch it.
It is shaped like a pyramid and divided into right and left
lobes. The lobes are further divided into segments. Unlike most other
organs, the liver gets blood from 2 sources: the hepatic artery
supplies the liver with blood rich in oxygen from the heart, and the portal vein carries
nutrient-rich blood from the intestines.

You cannot live without your liver. It has several important
functions:
- It breaks down and stores many of the nutrients absorbed
from the intestine that your body needs to function. Some nutrients
must be changed (metabolized) in the liver before they can be used by
the rest of the body for energy or to build and repair body tissues.
- It makes most of the clotting factors that keep the body
from bleeding too much when you are cut or injured.
- It secretes bile into the intestines to help absorb
nutrients (especially fats).
- It plays an important role in removing toxic wastes from
the body.
The liver is made up of several different types of cells. This
is why several types of malignant (cancerous) and benign
(non-cancerous) tumors can form in the liver. These tumors have
different causes, are treated differently, and have a different
prognosis (outlook for health or recovery).
Benign tumors
Benign tumors sometimes grow large enough to cause problems,
but they do not grow into nearby tissues or spread to distant
parts of the body. If they need to be treated, the patient can usually
be cured with surgery.
Hemangiomas
The most common type of benign liver tumor, hemangiomas start
in blood vessels. Most hemangiomas of the liver cause no symptoms and
do not need treatment. But some may bleed and need to be
removed surgically.
Hepatic adenomas
These are benign tumors that start from hepatocytes (the main
type of liver cell). Most cause no symptoms and do not need treatment.
But some eventually cause symptoms, such as pain or a mass in the
abdomen (stomach area) or blood loss. Because there is a risk that the
tumor could rupture (leading to severe blood loss) and a small risk
that it could eventually develop into liver cancer, most experts
usually advise surgical removal if possible.
The use of certain drugs may increase the risk of getting
these tumors. Women have a higher chance of having one of these tumors
if they take birth control pills, although this is a rare complication.
Stopping the pills can sometimes cause the tumor to shrink. Men who use
anabolic steroids may also develop these. Adenomas may shrink when the
drugs are stopped.
Focal nodular hyperplasia
Focal nodular hyperplasia (FNH) is a tumor-like growth of
several cell types (hepatocytes, bile duct cells, and connective
tissue). Although FNH tumors are benign, it can be hard to tell them
apart from true liver cancers, and doctors sometimes remove them when
the diagnosis is unclear. If you have symptoms from an FNH tumor, it
can be surgically removed and you can be cured.
Both hepatic adenomas and FNH tumors are more common in women
than in men.
Cancerous tumors that start in the liver
Several types of cancer can start in the liver.
Hepatocellular carcinoma (HCC) or
hepatocellular cancer
This is the most common form of liver cancer in adults. It is
also sometimes called hepatoma
because it comes from the hepatocytes (the main type of liver cell).
About 3 out of 4 cancers that start in the liver are this type.
Hepatocellular cancers can have different growth patterns:
- Some begin as a single tumor that grows larger. Only late
in the disease does it spread to other parts of the liver.
- A second type seems to start as many smaller
cancer nodules throughout the liver -- not just a single tumor. This is
seen most often in people with
cirrhosis (chronic liver damage) and is the most common pattern seen in
the United States.
Under a microscope, doctors can distinguish several subtypes
of HCC. Most often these subtypes do not affect treatment or prognosis
(outlook). But one of these subtypes, fibrolamellar, is
important to recognize. This type is rare, making up less
than 1% of HCCs. The patients with this type are usually
younger (below age 35), and the rest of
their liver is not diseased. This subtype has a much better outlook
than other forms of HCC.
Intrahepatic cholangiocarcinomas (bile duct
cancers)
About 10% to 20% of cancers that
start in the liver are intrahepatic cholangiocarcinomas. They start in
the small bile ducts (tubes that
carry bile to the gallbladder) within the liver. (Most
cholangiocarcinomas actually start in the bile ducts outside the
liver.)
Although the rest of this document deals mainly with
hepatocellular cancers, cholangiocarcinomas are often treated the same
way. For more detailed information on this type of cancer, see the
separate American Cancer Society document, Bile Duct (Cholangiocarcinoma)
Cancer.
Angiosarcomas and hemangiosarcomas
These are rare cancers that begin in blood vessels of the
liver. People who have been exposed to vinyl chloride or to thorium
dioxide (Thorotrast) are more likely to develop these cancers. See the
section "What
are the risk factors for liver cancer?" Other
cases are thought to be due to exposure to arsenic or radium, or to an
inherited condition known as hemochromatosis. In about half of all
cases, no likely cause can be identified.
These tumors grow quickly and are usually too widespread to be
removed surgically by the time they are found. Chemotherapy and
radiation therapy may help slow the disease, but most patients do not
live more than a year after the diagnosis.
Hepatoblastoma
This is a very rare kind of cancer that develops in children,
usually in those younger than 4 years old. The cells of hepatoblastoma
are similar to fetal liver cells. About 70% of children with this
disease are treated successfully with surgery and chemotherapy, and the
survival rate is greater than 90% for early-stage hepatoblastomas.
Secondary liver cancer
Most of the time when cancer is found in the liver it did not
start there but has spread (metastasized) from somewhere else in the
body, such as the pancreas, colon, stomach, breast, or lung. These
tumors are named and treated based on their primary site (where they
started). For example, cancer that started in the lung and spread to
the liver is called lung cancer with spread to the liver, not liver
cancer. In the United States and Europe, secondary (metastatic) liver
tumors are more common than primary liver cancer. The opposite is true
for many areas of Asia and Africa.
For more information on liver metastases from different types
of cancer, refer to the American Cancer Society documents on these
cancer types, and to our document, Advanced Cancer.
Most of the
remaining content in this document refers only to hepatocellular cancer.
Last Medical Review: 11/05/2009 Last Revised: 11/05/2009
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