Fine Needle Aspiration Biopsy or Core Needle Biopsy

General Description

Aspiration biopsy involves obtaining a sample of tissue or fluid from the body with the help of a syringe to analyze it in the laboratory and determine the nature of a disease (infections, inflammatory processes) or if it contains cancer cells. Depending on the type and quantity of material that needs to be obtained, a different type of needle is used.

Fine Needle Aspiration (FNA) uses a very narrow hollow needle to aspirate a sample from the area suspected of malignancy. One of its main advantages is that it is a quick, minimally invasive procedure that leaves no scars. However, it may provide a false negative if the needle fails to aspirate enough cancerous cells or if it does not reach them at all.

When the chosen needle is thicker, it is referred to as Core Needle Aspiration (CNA). It may cause some discomfort after the puncture, which disappears shortly after, but it does not leave visible marks on the skin.

If the area to be studied is not easily accessible, an imaging test is used to guide the needle through the body. Ultrasound is typically used for this purpose.

When is it indicated?

Fine needle biopsies are useful for taking small tissue samples or aspirating fluids. They are commonly used to analyze nodules in the thyroid or breast, as well as to study liver abnormalities or analyze thyroid or breast cysts.

Core needle biopsy is indicated to remove small tissue wedges from areas that are not easily visible in imaging tests or where calcifications have formed. It is also commonly used in breast biopsies or to extract samples from bones, muscles, or the liver.

How is it performed?

In an aspiration biopsy, no anesthesia is used, making recovery faster. The procedure is usually performed in a sterilized room close to the laboratory, as pathologists verify the adequacy and sufficiency of the sample before the patient leaves, in case it needs to be repeated.

Whether a fine or coarse needle is used, the steps are the same. First, the skin is disinfected, then the needle is inserted until the desired point is reached. Once in place, the plunger is pulled to fill the syringe with tissue.

To prevent the sample from degrading or oxidizing, it should be fixed with formalin (formaldehyde – CH2O) and buffered immediately after the procedure. After preparing it according to the specific needs, to clearly observe the characteristics of the different cells, the sample is placed on a glass slide and examined under a microscope.

Risks

Aspiration needle biopsy is a minimally invasive and safe technique that does not pose significant health risks or complications.

In some cases, particularly with core needle biopsies, there may be bleeding after the sample is extracted, which stops within a few minutes after pressure is applied. Rarely, an infection may occur, especially if the disease being analyzed is of bacterial or viral origin. In lung punctures, there is a minimal risk of pneumothorax.

What to expect from a fine or core needle aspiration biopsy

On the day of the biopsy, it is recommended to wear comfortable clothing that can be easily removed, as the patient will need to wear the medical center's gown.

Once in the sterile room, the patient lies on a stretcher in the position recommended by the specialists to facilitate access to the area to be investigated. Anesthesia is not necessary, and the procedure is outpatient, allowing the patient to resume their routine as soon as it is completed. However, to avoid complications, it is often necessary to rest for some time after the puncture before leaving the medical center. Intense exercise is also discouraged on the day of the test.

If bleeding, swelling, or discomfort do not subside or worsen, the patient should seek urgent medical attention.

Although results may be available the same day, it usually takes a few days to receive them.

Specialties requesting aspiration biopsy

Pathologists analyze the sample collected by oncologists, gynecologists, or endocrinologists.