Biopsy is a medical test that involves removal of tissue in order to examine it for disease. The tissue samples may be taken from any part of the body.
There are several types of biopsies. Some biopsies involve removing a small amount of tissue with a needle while others involve surgically removing an entire lump or suspected tumor.
Biopsies may also be performed using imaging guidance such as ultrasound, x-ray, computed tomography (CT), or magnetic resonance imaging (MRI).
What are biopsies used for?
Diagnosing tumors and cancers
Tumors may be graded as cancerous (malignant) or non-cancerous (benign) with the help of biopsies
Biopsies of cancers help to grade the tumor. The microscopic structure of the tumor often gives clues to the nature, rate of growth, aggressiveness of the cancer. The cancer is staged based on this. Staging helps to determine the plan of treatment and helps to predict the outcome or prognosis of the cancer.
Biopsies can help identify other conditions such as infections and autoimmune disorders. Bone biopsy for example helps in diagnosis of bone infections. Bone marrow biopsy is used to diagnose cancer in the blood, such as leukemia and also for effects of drugs, toxins and infections.
Where and how are biopsies performed?
Biopsies may be performed on almost all organs like breast, kidneys, liver, bone marrow, bone, skin, lung, lymph nodes, muscles, nerves, testes, thyroid, bladder, heart, neck, prostate etc. Usually biopsies are performed as an out-patient procedure and do not require admission.
Types of biopsy
There are many different types of biopsy procedures:
- Needle biopsy – A fine needle is used to remove a small amount of tissue from the tumor or growth. This is called fine needle aspiration cytology (FNAC).
- Vacuum assisted biopsy — thicker, hollow needle removes cores of tissue with a single insertion of a vacuum assisted probe.
- Surgical biopsy – Here a small surgery is performed. A small or whole of the tumor is excised and removed for examination. This is a more extensive procedure and may require hospital stay. When an entire lump or suspicious area is removed, the procedure is called an ''excisional biopsy''. When only a sample of tissue is removed with preservation of the histological architecture of the tissue’s cells, the procedure is called an ''incisional biopsy'' or ''core biopsy''.
How is biopsy analysed?
The biopsy tissue is sent to the laboratory wherein a pathologist makes microscopically thin slices from it and fixes the slices onto a glass slide. This is then examined under the microscope after staining it with special dyes.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)