A biopsy is a medical procedure that involves taking a small sample of body tissue so it can be examined under a microscope.
A tissue sample can be taken from almost anywhere on or in your body, including the skin, organs and other structures.
The term ‘biopsy’ is often used to refer to both the act of taking the sample and the tissue sample itself.
When a biopsy may be needed
A biopsy can be used to investigate abnormalities, which can be:
- functional – such as kidney or liver problems
- structural – such as swelling in a particular organ
When the tissue sample is examined under the microscope, abnormal cells may be identified. This can help to diagnose a specific condition.
If a condition has already been diagnosed, a biopsy can also be used to assess its severity (such as the degree of inflammation) and grade (such as the aggressiveness of a cancer). This information can be very useful for:
- deciding on the most appropriate treatment
- assessing how well a person responds to a particular type of treatment
- helping to determine a person’s overall prognosis (outlook)
Examples of conditions where a biopsy may be helpful include:
- inflammation, such as in the liver (hepatitis) or kidney (nephritis)
- infection, such as in lymph nodes – for example, tuberculosis
- various skin conditions
It’s not usually possible to tell whether a lump or growth on your skin or inside your body is cancerous (malignant) or non-cancerous (benign) by clinical examination alone, which is why a biopsy is often required.
Types of biopsy
There are many ways of getting a tissue sample. It depends on the type of tissue being collected and where in the body it’s being taken from.
Imaging techniques, such as X-ray, ultrasound, CT scanning or MRI scanning is often used to guide many types of biopsy.
A punch biopsy can be used to investigate a variety of skin conditions.
During a punch biopsy, a special surgical instrument is used to make a small hole in the skin and remove samples of the top layers of tissue. If you have a punch biopsy, you’ll usually be given local anaesthetic to numb the area.
Alternatively, a scalpel (a sharp medical knife) may be used to remove a small amount of surface skin. The wound will be closed using stitches.
A fine-needle aspiration (FNA) biopsy is often used to take cell samples from organs or from lumps that are below the surface of the skin. If a larger sample is needed, a core needle biopsy (CNB) will be used instead.
For core biopsies, after local anaesthetic has been given, a hollow needle is inserted through the skin and into the area being examined. X-ray, ultrasound, CT or MRI scanning will often be used to help guide the needle to exactly the right place.
When the needle is in position, it will cut out a small sample of tissue. For core biopsies, local anaesthetic is usually used to numb the area, so that you won’t experience any pain or discomfort.
In many cases, a needle biopsy can be used to get more information about a breast lump. The needle is inserted into the lump and a sample of tissue will be taken for testing.
A core needle biopsy (CNB) is often used to obtain a larger tissue sample. In some cases, when a cyst (a benign fluid-filled swelling) is suspected, a fine needle will be used to drain the fluid and the cells sent for examination (cytology).
A thicker, hollow needle is used for taking organ biopsies, such as of the liver or kidneys. These are often carried out with imaging guidance (ultrasound or CT). You may be asked to hold your breath for a few seconds while the needle is inserted into your abdomen (tummy).
A thick needle is used to take samples of bone marrow (the soft, jelly-like tissue found in the hollow centre of large bones).
Bone marrow biopsies can be carried out for a number of different reasons, including to find out why you have a low or high number of:
- red blood cells
- white blood cells
- platelets (blood-clotting cells)
A large number of different health conditions may be responsible for these types of blood abnormalities. Where a diagnosis has already been made, samples of marrow may be taken to check how well treatment is working – for example, in leukaemia.
Samples of bone marrow are also sometimes taken to check how well treatment for leukaemia is working, or to determine how far certain types of cancer have progressed (what stage it’s at).
Bone marrow biopsies are usually taken from the top of the pelvic bone, just below your waist. You’ll usually have a local anaesthetic to numb the area. You may also be given a sedative to help you relax and cope with any discomfort or anxiety.
An endoscope is a medical instrument used to look inside your body. It’s a thin, flexible tube with a light and a camera at one end. Small cutting tools can also be attached to the end of an endoscope to allow the endoscopist (surgeon, doctor or nurse specialist) to take a tissue sample.
An endoscope can be inserted down your throat (upper gastrointestinal), or from below through the anus (lower gastrointestinal), depending on the area being examined.
The type of anaesthetic used will also depend on the area of the body being investigated and the entry point of the endoscope.
An excisional biopsy is used to remove a larger area of tissue, such as a lump, for closer examination. The type of anaesthetic used will depend on where the tissue is.
A biopsy is sometimes carried out during an operation for a related or unrelated reason.
A tissue sample is taken during surgery and can be checked immediately (known as a ‘frozen section’). This means that the surgeon can get the results while the operation is in progress. This can help them decide how to manage the treatment.
A lump found during surgery may be removed completely if the patient is still under anaesthetic, providing that previous consent has been given.
Testing the tissue sample
After a tissue sample has been taken, it will be sent to a laboratory to be examined under a microscope.
Closely examining the cells in the tissue sample enables histologists (doctors who specialise in studying the structure of tissues) to determine whether they’re normal or abnormal. For instance, cancerous cells look and behave differently to normal cells.
As well as looking at the tissue sample, chemical or genetic tests may also be carried out, if needed. In cystic fibrosis, for example, a chemical test can be used to help diagnose the condition. The type of stains and tests that are used when the tissue is examined under the microscope will depend on the medical condition being investigated.
Most biopsies will only require local anaesthetic, which means you won’t need to stay in hospital overnight. However, an overnight stay is sometimes required when the biopsy is carried out under general anaesthetic.
After having a biopsy, you won’t usually feel any pain. However, if you’ve had a tissue sample taken from a major organ, such as your liver or bone marrow, you may feel a dull ache or some slight discomfort. Your doctor or surgeon may recommend painkillers to help relieve this.
If an incision is needed to remove a tissue sample – for example, during an excision biopsy – stitches may be needed to close the wound, or a dressing may need to be applied.
If tissue is removed from an internal organ, such as your liver or kidneys, you’ll need to stay in hospital for a few hours after the procedure. This is so you can rest and hospital staff can make sure there’s no internal bleeding. It’s rare for serious bleeding to occur after having a biopsy. But if it does, you may need to have an operation or a blood transfusion. In rare cases, another procedure or operation may be needed.
Women who have had tissue samples taken from their reproductive system, such as the lining of the cervix (neck of the womb), may experience some temporary light vaginal bleeding. Painkillers can be used to treat any cramping.
Getting your results
How quickly you get the results of a biopsy will depend on the urgency of your case and your local hospital’s policy.
Results are often available within a few days. However, this is difficult to predict, because further tests may be needed after the first examination of the sample. It’s sometimes necessary to send the microscope slides away, to get another specialist opinion.
If a biopsy is carried out during surgery, in some cases a different processing method may be used, known as a ‘frozen section’. This enables the surgeon to get a preliminary result, which can be used to help guide treatment while it’s in progress.
Your GP, hospital consultant or practice nurse will give you your results and explain what they mean. A biopsy is sometimes inconclusive, which means it hasn’t produced a definitive result. In this case, the biopsy may need to be repeated, or other tests may be required to confirm your diagnosis.