Biopsy is the removal of a small piece of tissue for laboratory examination. A variety of techniques are used to obtain tissue samples, depending on their site.

Incisional Biopsy

Samples from tissues on or near the body surface are easily obtained for microscopic examination, using local anaesthetic and a small incision.

Needle Biopsy

Tissues and organs deeper in the body may be sampled by needle biopsy ), local anaesthetic is injected, and a hollow needle with a cutting tip inserted into the organ or tissue. ULTRASOUND or CAT SCANNING may be used to guide the needle to the correct site. The needle is then rotated while slight suction is applied to draw fragments of the tissue into its bore.

Endoscopic Biopsy

Specimens from abnormal areas in the lining membranes or walls of hollow organs may be taken during ENDOSCOPY (internal examination via a viewing instrument).

Open Biopsy

Samples of diseased tissue are obtained during surgical opening of a body cavity. Biopsy specimens are treated in one of two ways

• In most cases the tissue is placed in preservative
  immediately. In the laboratory it is embedded in wax and finely sliced. The slices of tissue are mounted on a glass slide. stained to demonstrate various characteristics, and examined under a microscope. This process, called histology or histopathology, takes about 2 days.
• If information about the tissue is needed more quickly, to discover whether. for example, a tumour found during open surgery is benign or malignant the tissue may be snapfrozen, sliced, and examined under the microscope immediately. This frozen section technique provides results within minutes.

Like any surgery, liver biopsy does have some risks, such as puncture of the gallbladder, bleeding, infection, and pain, but these complications are rare. Another technique used for liver biopsy is guiding the needle into the liver through the abdomen or chest using various imaging techniques. This approach is used when there are localized tumors identified by ultrasound or computed tomography. Liver biopsy is also used after liver transplantation to determine the cause of elevated liver tests and determine if rejection is present. Patients who have undergone liver transplantation often require numerous liver biopsies in the early weeks to months following the surgery to allow accurate diagnoses of whether the new liver is being rejected or whether other problems have developed. Occasionally, liver biopsy is repeated if the clinical condition changes or to assess the results of medical therapy, such as drug treatment of chronic viral hepatitis with interferon or prednisone therapy of autoimmune hepatitis.

Purpose

A liver biopsy may be ordered to evaluate any of the following conditions or disorders:

• Cirrhosis.
• Hemochromatosis, which is a condition of excess iron in the liver.
• Jaundice.
• Primary cancers of the liver, such as hepatomas, cholangiocarcinomas, and angiosarcomas.
• Repeated abnormal results from liver function tests.
• Unexplained swelling or enlargement of the liver.

Precautions

Some patients should not have percutaneous liver biopsies. They include patients with any of the following conditions:

• A watery (hydatid) cyst.
• An infection in either the cavity around the lungs, or the diaphragm.
• A history of unexplained bleeding.
• A liver tumor that contains a large number of blood vessels.

Signs and symptoms of potential complications of liver biopsy

• Abdominal swelling or bloating.
• Pain, swelling, redness or discharge around the needle insertion sites.
• Chest pain.
• Dizziness or fainting.
• Nausea or vomiting.

Reasons to avoid liver biospy

Some conditions make it unsafe to perform a percutaneous liver biopsy. In general, these include:

• A large amount of fluid in the abdomen.
• Severe anemia.
• Jaundice caused by obstruction of the bile ducts.
• Severe kidney failure.
• Significant blood clotting abnormalities.