Biopsy is the term used to describe a procedure that removes tissue samples from the body in order to identify the presence or degree of a disease. Once the samples are obtained, they are sent to a pathologist who examines the tissue under a microscope, looking specifically at the tissue cells' type, shape and activity. In some cases, the tissue may be frozen or treated with chemicals. When ready, these particular samples are sliced into thin segments, placed on glass slides, dyed to improve contrast and observed under a microscope.
Often, a biopsy is called for after a physician has located a lump or suspicious area during a physical exam or imaging test. Biopsy results are typically available within a few days, but may take longer if a clear diagnosis cannot be made.
Types of Biopsies
There are several types of biopsies, including:
With this kind of biopsy, one or more incisions are made in the skin in order to take out all of a lump of tissues (excisional) or part of a lump of tissue (incisional). It is performed under local or general anesthesia, depending on the location of the tumor, and the patient may need to remain in the hospital for observation.
A surgical biopsy may be performed if other biopsy results have not made a clear diagnosis, or when a mass or suspicious area of cells are unable to be accessed with other biopsy measures.
Fine Needle Aspiration Biopsy vs. Core Needle Biopsy
If the area being sampled is close to the surface of the skin, the surgeon will typically use a needle to obtain tissue samples. Should the sample area be deep below the surface of the skin, this type of biopsy may be performed using ultrasound or CT guidance to help with placement of the needle. For suspected prostate or kidney cancer, needle biopsies are a common method of obtaining tissue samples for biopsy.
During fine needle aspiration (FNA), an extremely fine needle and syringe are used to extract tiny amounts of fluid and tissue from a lump or suspicious area. Since what is taken is so small, it takes less time to process a FNA sample. However, the limited amount of tissue for testing can make it difficult to confirm a diagnosis. In such instances, then a core needle biopsy or other kind of biopsy may be required.
A core needle biopsy (CNB) uses a needle armed with a cutter to remove "cores" of tissue from a suspicious area or lump. Because the needle has a wider diameter than that which is used during FNA, a larger sample—approximately 1/16 inch in diameter and 1/2 inch long—can be taken. This may increase the accuracy of the laboratory analysis.
Both procedures require local anesthesia and can be performed in a doctor's office or clinic.
An endoscope is a thin tube with a light source and video camera at its tips. It is not only used to see inside the body's organs and structures, there is a hallow channel within it that allows small instruments like forceps or graspers to be passed through so that tissue samples can be extracted for examination. The type of endoscope will depend on the part of the body being examined. In urology, the ureteroscope and cystoscope are frequently used when obtaining tissue from the interior of the bladder or kidney.
What Can a Biopsy Diagnose?
- Glomerulonephritis: swelling of the small blood vessels in the kidneys
- Nephropathy: Damage or disease of the kidneys
- Interstitial nephritis: inflammation between the kidney tubules
- Orchitis: inflammation of one or both testicles
- Spermatocele: A sac found in the testicle that is filled with fluid and dead sperm cells
- Prostatitis: Inflammation of the prostate
- Interstitial cystitis: Inflammation of the bladder wall
Biopsies can additionally be used to diagnose:
- Some infectious diseases
- Metabolic disorders
- Whether an organ that has been transplanted is being received or rejected by the body
- Male infertility (A testicular biopsy—either surgical or needle—may be performed when the cause of infertility is not determined via other methods)
Biopsy to Determine Cancer Stages
If cancer is found to be present in the tissue samples taken, the findings can be used to determine the stage of cancer. The cancer is given a grade—often 0 to 4—and this is based on how the cancer cells appear under the microscope.
- Stage 0: Also referred to as in situ, this stage is characterized as the early onset of cancer, when the cancerous cells are localized to one part of the body and there is a chance that they may never spread.
- Stage 1: The cancerous cells have the ability to spread but, for now, remain localized to one part of the body.
- Stage 2 and 3: Cancerous cells have spread beyond the localized site to nearby tissue, but not to distant parts of the body.
- Stage 4: Cancerous cells have spread to distant regions of the body.
Risks associated with a biopsy include:
- Disturbance of the cancerous cells (might cause cells to further spread)
- Pain and bruising
- Injury to nearby organs and structures
Urology tests and procedures: Kidney biopsy. Johns Hopkins Health Library.
Diagnosing bladder cancer. Weill Cornell Medical College, Department of Urology.
Prostate biopsy. UCLA, Department of Urology