What is a biopsy ?

Dr David Howdijam *

Lung biopsy guided by computertomography: Lung cancer. :: Pix - Wikipedia/Hellerhoff

A biopsy is a sample of tissue taken from the body in order to examine it more closely. A doctor recommends a biopsy when an initial test suggests an area of tissue in the body is not normal.

An area of abnormal tissue is called a lesion, a tumour, or a mass. These are the general terms used to emphasise the unknown nature of the tissue. The suspicious area may be noticed during a physical examination or inside the body in an imaging test.

WHY ARE BIOPSIES DONE?

A biopsy might be recommended when an important medical question comes up which the biopsy could help answer.

o Biopsies are often done to diagnose cancer. A biopsy is commonly done if one has 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 whether the lump is a cancer is to take a biopsy and look at the cells under the microscope. Cancer cells look different from normal cells.

o 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.

o Sometimes one may already have a condition, but a biopsy can help to assess its severity. For example, to see how severe inflammation is within an organ such as the liver.

o In some cases, a biopsy of normal-appearing tissue may be done. This can help check for cancer spread or rejection of a transplanted organ.

Types of biopsies

There are many kinds of biopsies. Nearly all of them involve using a sharp tool to remove a small amount of tissue. Some types of common biopsies are:

o A 'needle' biopsy: This can sample tissue from organs or lumps beneath the skin. A special long needle is inserted through the skin into abnormal lumps, the kidney, liver, thyroid, bone marrow etc. to obtain a small sample of the tissue. Sometimes, a local anaesthetic agent is injected at the site prior to this type of biopsy to make the procedure painless.

o A 'punch' biopsy: This 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 the skin. To make the procedure painless, the doctor may inject some local anaesthetic agent or put on some anaesthetic cream beforehand.

o Ultrasound-guided biopsy: An ultrasound scanner helps a doctor direct the needle into the lesion.

o CT-guided biopsy: A person rests in a CT-scanner; the scanner's images help doctors determine the exact position of the needle in the targeted tissue.

o Bone marrow biopsy: A large needle is used to enter the pelvis bone to collect bone marrow.

o Bone biopsy: A bone biopsy is used to look for cancer of the bones. This may be performed via the CT scan technique or by an orthopaedic surgeon.

o Endoscopic biopsy: A biopsy of tissue is taken during an endoscopy procedure. For example, during a gastroscopy (when endoscopy is passed through the mouth and into the stomach), the doctor may take a biopsy of the stomach lining.

o Excisional biopsy: This means an entire lump is removed to be examined. This may be done under local or general anaesthesia, depending upon the site of the lump.

How to prepare for the test?

Before scheduling the biopsy, one should tell the doctor and the nurses about any medications he or she is taking at the moment, including herbal preparations and supplements. One may be asked to stop taking medications for a while, particularly those that can make one bleed. Such medications include aspirin and nonsteroidal anti-inflammatory medications.

How will the test feel?

Biopsies vary greatly according to how difficult the tissue is to obtain. A minimally invasive biopsy (for example, most skin biopsies) may be done in the doctor's office during the same visit the lesion is discovered. More invasive biopsies may be done in a hospital, a surgery centre, or a specialised doctor's office. One would make a separate appointment for the biopsy.

In a needle biopsy, one will feel a sharp pinch at the site of the biopsy.

In a biopsy where excision is required, local or general anaesthesia is often given to make the whole procedure painless.

What happens after the biopsy?

After the tissue is collected and preserved, the pathologist examines the biopsy tissue under a microscope. By noting the type of cells in the tissue, their shape and internal activity, the pathologist makes a diagnosis of the problem.

The time it takes to get the results from a biopsy can vary. Final, accurate conclusions on biopsies take 2-3 days, or may take longer. Sometimes, during a surgery, a pathologist may read a biopsy and report back to the surgeon within a few minutes. This helps the surgeon to determine the cause of a lump inside the body, which may enable him to decide on how to proceed with the operation.

One would need to follow up with one's regular doctor to discuss on the biopsy results.