Lymph node biopsy is a test in which a lymph node or a piece of a lymph node is removed for examination under a microscope.

The lymphatic system is made up of lymph nodes connected by lymph vessels. The nodes produce white blood cells (lymphocytes) that fight infections. When an infection is present, the lymph nodes swell, produce more white blood cells, and attempt to trap the organisms that are causing the infection. The lymph nodes also try to trap cancer cells.

The test is done in an operating room in a hospital, or at an outpatient surgical facility. There are two ways the sample may be obtained:

• Needle biopsy
• Open biopsy

A needle biopsy involves inserting a needle into a node to obtain the sample. You will lie on the examination table. The biopsy site will be cleansed, and a local anesthetic will be injected. The biopsy needle is then inserted into the node. A sample is removed, pressure is applied to the site to stop the bleeding, and a bandage is applied.

An open biopsy consists of surgically removing all or part of a node. You will lie on the examination table. You may be given a sedative if you prefer. The skin over the biopsy site is cleansed, and a local anesthetic is injected (occasionally, a general anesthetic is given). A small incision is made, and the lymph node or part of the node is removed. The incision is then closed with stitches and bandaged.

The sample is then sent to the laboratory for examination.

Tell your health care provider about any drug allergies you have, which medications you are taking (including any supplements or herbal remedies), if you have bleeding problems, and if you are pregnant. You must sign a consent form.

When the local anesthetic is injected, there will be a prick and a mild stinging. The biopsy site will be tender for a few days after the test.

The test is used to help determine the cause of lymph node enlargement (swollen glands). It may also determine whether tumors in the lymph node are cancerous or noncancerous.

Enlarged lymph nodes may be caused by a number of conditions, ranging from very mild infections to serious malignancies. Benign conditions can often be distinguished from cancerous and infectious processes by microscopic examination. The pathologist may also perform additional tests on the lymph node tissue to assist in making a diagnosis.

The examination of the tissue may show cancerous or noncancerous tumors, or the presence of infection.

Additional conditions under which the test may be performed:

• Hodgkin's lymphoma
• Non-Hodgkin's lymphoma
• Sarcoidosis

With this test there is a small chance of infection or bleeding. Additionally, there is a moderate risk of nerve injury, localized paralysis, or numbness when the biopsy is performed on a lymph node close to nerves.