A biopsy is when a small sample of tissue is removed from a part of the body. The sample of tissue is then examined under the microscope to look for abnormal cells. Sometimes the sample is tested in other ways. For example, it may be tested with chemical reagents to help identify abnormal chemicals in the tissue sample. Sometimes tests are done on the sample to look for bacteria or other germs.
Why are biopsies done?
- Biopsies are often important to diagnose cancer. A biopsy is commonly done if you have a lump or swelling of a part of the body where there is no apparent cause. In these situations often the only way to confirm that the lump is a cancer is to take a biopsy and look at the cells under the microscope. Cancer cells look different to normal cells.
- Various other conditions can be diagnosed by taking a biopsy. For example, inflammation within organs such as the liver or kidney can be seen on a biopsy sample. There are various causes of inflammation, and sometimes the biopsy can identify particular cells that occur with specific types of inflammation.
- Sometimes you may already have a condition, but a biopsy can help to assess it's severity. For example, to see how severe inflammation is within an organ such as the liver.
How are biopsies done?
There are many different procedures to obtain biopsy samples. It depends on what part of the body the sample is needed from. For example:
- A 'punch' biopsy is useful to diagnose a range of skin conditions. A special instrument punches a small hole through the top layers of the skin to remove a sample of skin. To make the procedure painless the doctor may inject some local anaesthetic, or put on some anaesthetic cream beforehand.
- A 'needle' biopsy can sample tissue from organs or lumps beneath the skin. For example, a special long needle can be inserted through the skin into the kidney, liver, thyroid, bone marrow, or abnormal lumps, etc. A small sample of the tissue can be obtained this way. The doctor will usually inject some local anaesthetic into the skin with a fine needle prior to this type of biopsy to make the procedure painless.
- Endoscopic biopsies. An endoscope is a thin flexible telescope which is used to 'look' into various parts of the body. A biopsy of tissue is commonly taken during these procedures. For example, during a gastroscopy (when an endoscope is passed through the mouth and into the stomach) the doctor may take a biopsy of the stomach lining.
- Excisional biopsy. This means an entire abnormal lump is removed to be examined. This may be done under local or general anaesthesia, depending on the site of the lump. For example, this type of biopsy may be done for certain breast lumps.
- Per-operative biopsy. Sometimes, when you are having an operation, a surgeon may remove a small sample of tissue which is examined within a few minutes. This may help the surgeon to determine the cause of a lump inside the body, which may help to decide on how to proceed with the operation.
Further information
The above is just a short guide. There are various other types of biopsy. Your doctor will be able to give further information on the type of biopsy you may be advised to have.
©EMIS and PIP 2006 Updated: February 2006
