What Is Fine Needle Aspiration?

This test is used to determine the status of a breast lump

Fine needle aspiration (FNA) is a procedure used to obtain a sample of cells from a breast lump to determine whether it's a cyst, an infection, a benign tumor, or cancer. FNA is usually chosen when a lump is likely a fluid-filled cyst, as the procedure is particularly helpful in distinguishing cysts from solid masses. Your doctor will use a very fine needle (much smaller than a blood draw needle) to draw out some fluid, which will be examined under a microscope by a pathologist.

Purpose of Test

Getting any breast lump checked out is a wise move. Having a fine needle aspiration may seem scary, but it's a safe, minor procedure that provides clear information about the nature of a lump.

If the lump turns out to be a cyst—a harmless, fluid-filled sac—the fluid can be drained out at the same time, relieving any pressure it may be causing.

Most breast lumps are not cancerous, but a small percent of them are malignant. In either case, the examination of the fluid resulting from your aspiration can give your doctor enough information to determine what the next steps should be to deal with the lump.

There are two main advantages of FNA, according to the American Cancer Society: One is that the skin doesn’t have to be cut, so there's no need for stitches and no scar. The other is that, in some cases, it’s possible to make a diagnosis the same day.

Risks and Contraindications

Risks with FNA are minimal. There's a slight chance of bleeding and infection at the injection site. You might be sore for a day or two after the procedure and experience some mild bruising and swelling.

Before the Test

There's little you need to do to prepare for fine needle aspiration, but the following information may be helpful to know in advance of the procedure.

Timing

It takes about 10 to 20 seconds to obtain each sample, and you may need two to four needle passes. The whole procedure from start to finish usually takes no more than half an hour, but you should allow time for filling out forms and waiting in the office.

You can expect results within two to three days of the test, possibly sooner.

Location

Fine needle aspiration is an outpatient procedure performed in a doctor's office or a medical clinic that has professionals trained in the technique and access to a pathology lab that can examine the fluid collected.

If ultrasound guidance is needed, the biopsy is usually done in a radiology department. This machine, which uses high-frequency sound waves to provide an ongoing image of the lump, enables the doctor to guide the needle to exactly the right spot.

Food and Drink

You're able to eat and drink normally before the procedure. Ask your healthcare provider whether you should stop taking any medicines before the procedure, such as blood thinners.

Cost and Health Insurance

Most private insurers, as well as Medicare, cover the cost of a breast biopsy when indicated. With some insurance companies, or when special techniques are recommended, you may need to obtain prior authorization.

Other Considerations

You won't be put to sleep during FNA, so you will be able to go about your life—return to work, take care of your family, drive a car—after having the procedure.

During the Test

You will interact with the physician performing the fine needle aspiration, but not the pathologist who will examine the sample and, ultimately, deliver the results.

Pre-Test

You'll undress from the waist up and wear a robe that opens in the front. After changing out of your clothes, and before the procedure begins, your doctor will ask if you have any questions. You will also be asked to sign an informed consent form, indicating you understand the purpose of the procedure and any potential risks.

You'll be awake during the procedure and positioned on your back. Your skin will be swabbed with an antiseptic solution to prevent infection.

You can ask for a local anesthetic to numb the area of your breast that the needle will enter, but the needle used for FNA is so fine that getting an anesthetic might hurt more than the biopsy itself.

Throughout the Test

Your doctor will locate the lump by feeling it or by using ultrasound to see it. Then, she will immobilize the lump and use a very fine-gauge needle to pierce it and draw out fluid with a syringe. If ultrasound is used, you may feel some pressure from the wand as the needle is inserted.

If no fluid comes out, the doctor may reposition the needle and try again.

Post-Test

Once the fluid is captured, the needle is removed, pressure is applied to prevent a bruise, and a bandage is used to cover the site.

After the Test

When performed by an experienced practitioner, fine needle aspiration is virtually free of significant complications.

The most common ones are slight bruising, tenderness, or swelling of the area for a few days following the procedure. These can be relieved with over-the-counter pain relievers like Tylenol (acetaminophen) and the application of cold compresses for short periods.

Call your doctor if you experience continued swelling or bleeding, a fever above 101 degrees F, and/or unrelenting pain.

Interpreting Results

A specially trained doctor called a pathologist will look at the biopsy fluid or tissue to see if it contains cancer cells. Test results can take up to two or three days, though sometimes they're available the same day. The pathology report will be sent to your doctor, who will call or have you come in to get the results.

  • A normal result means there's no sign of cancer or other breast problems.
  • An abnormal result doesn't mean you have cancer or precancer, but perhaps any number of benign breasts conditions, including a fibroadenoma and fat necrosis.

The color of the fluid drawn out of the lump during the procedure will give some clues about its nature. If the fluid is clear or watery and not bloody, and the lump shrinks as a result of the aspiration, it's most likely a cyst. Sometimes the fluid will be white, yellow-green, brown, or bloody, but only in rare cases will this mean that the lump is cancerous.

If the needle draws out small bits of tissue and very little fluid it, that indicates a solid mass.

Needle aspiration is 80 percent to 85 percent accurate in giving a clear indication as to whether a breast lump is a cyst or a solid breast mass. Sometimes, though, the results don't give a clear diagnosis.

Fine needle aspiration may result in draining a cyst, causing the lump to go away. This is a good indication that the lump was not cancerous. However, some cysts do refill, and if they become bothersome, can be surgically removed.

Follow-Up

The pathology report will help you and your doctor talk about the next steps, if any. If your doctor still has concerns for some reason, she may recommend doing another FNA or another type of biopsy:

  • Core needle biopsy: A core needle biopsy requires the use of a larger needle than a fine needle biopsy and removes a small cylinder ("core") of tissue, rather than a collection of cells. It's often done using ultrasound or magnetic resonance imaging (MRI) to help locate the right area for the biopsy.
  • Stereotactic biopsy: With this method, a 3D image of the breast is made using a computer and mammogram results. The 3D image then guides the biopsy needle to the exact site of the breast lump.
  • Open (surgical) biopsy: This type of biopsy may be incisional (involving the removal of part of the abnormality) or excisional (removing all of the abnormality).

If it's breast cancer, you will likely be referred to a breast cancer specialist, who may recommend more scans, lab tests, or surgery. Your medical team will use the pathology report and the results of the other tests to determine the stage of cancer and to design the best treatment plan for you.

A Word From Verywell

Undergoing, waiting for, and receiving test results can be extremely anxiety-provoking. But keep in mind that 80 percent of women who have a breast biopsy do not have breast cancer. Even if a cancer is found, the majority of these cancers will be early-stage tumors. Treatment of these cases has improved, with newer options significantly reducing the risk of recurrence and often being far less invasive than older ones. As for metastatic cases, which is present in less than 5 percent of women at the time of diagnosis, treatments are improving and life expectancy is increasing.

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