Fine Needle Aspiration Biopsy (FNAB)

Occasionally, if the doctor can palpate (feel) a breast mass, a very small needle can be used to aspirate (withdraw) tissue samples. This tissue will be sent to the laboratory for examination by a pathologist. Even if a breast mass cannot be felt, a FNAB can be performed with ultrasound guidance.  The ultrasound allows the doctor to watch the needle on the monitor as it moves toward and into the mass. Final pathology reports are available within 3 business days. You will be notified of these results by Center for Breast Health staff. Your primary healthcare provider may also notify you of these results.

There is no special preparation for this type of biopsy. It takes only a few seconds to complete and is well tolerated. As this type of biopsy uses a very small needle, the use of local anesthetic is generally not used. Injection of local anesthetic can change how the breast tissue lying on top of the mass feels. Often the injection causes the doctor to be unable to locate the mass again. If the mass cannot be easily identified, it is impossible to obtain an adequate sample of the area in question.

While firmly holding the mass in place with one hand, the doctor will cleanse your skin with an antiseptic or alcohol solution. A small needle, attached to a syringe, will then be inserted gently into the mass. The syringe is used to apply suction during the procedure. Because the needle used in this procedure is so small, the suction applied by the syringe, increases the amount of tissue obtained. The more tissue available for examination, the greater the probability of an accurate diagnosis from this minimally invasive procedure.

After The Procedure

A small bandaid will be applied to the biopsy site. You may notice 1 or 2 drops of blood on this bandaid, but you should not experience enough bleeding to soak through the bandaid. 

You may notice a small amount of  bruising at the biopsy site. This bruising will gradually fade and should be completely gone in 5-7 days.

If you notice excessive swelling, bruising, bleeding, redness and/or heat at your biopsy site, please call us at 563-421-7625, or call your primary healthcare provider.

You may apply ice to the biopsy site to relieve bruising and swelling. Do not apply the ice directly to your skin. Wrap the ice or ice pack, in a washcloth and do not use longer than 15 minutes, at each application, to avoid damage to the skin from frostbite. You may apply the ice pack every 1-2 hours, as needed.

You may use acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) every 4-6 hours as needed for pain. Do not use aspirin, or aspirin containing products, to reduce the risk of bleeding.

Fine needle aspiration biopsies are not 100% accurate. Even with ultrasound guidance it is possible for the needle to withdraw normal breast tissue from nearby a breast cancer and return a negative (non-cancer) pathology report. If the biopsy results do not provide a clear diagnosis a second FNAB, or even a different type of biopsy, should be considered. You will be informed of the pathology results by Center for Breast Health staff. Your primary healthcare provider may also inform you of the results.

Occasionally during this procedure, fluid may be withdrawn from a breast mass. This fluid can range in color from light yellow to dark green. It may be clear or cloudy. These are all normal color variations of benign cyst fluid.  Benign cyst fluid is not sent to the laboratory for further examination. However, if the fluid is bloody, very viscous (thick), or purulent (pus-filled), it is sent to the laboratory for examination for an infection or possible cancer.