Breast Fine Needle Aspiration (FNA)

Authors:  Dr Natacha Borecky*
                        A/Prof Liz Wylie*

What is a breast fine needle aspiration?

A breast fine needle aspiration (FNA) removes some fluid or cells from a breast lesion (a cyst, lump, sore or swelling) with a fine needle similar to that used for blood tests. The sample of fluid or cells (or tissue) is examined by a specialist doctor (a cytologist). An FNA can assist the doctor to determine the nature or diagnosis of a lesion and, if necessary, to plan treatment.

If a lesion cannot be felt from the surface of the skin, ultrasound images or pictures may be used by the radiologist or other specialist doctor carrying out the FNA to guide the needle into the lesion.

Breast FNA may also be used to aspirate (draw fluid from) a known cyst, either removing it completely or relieving discomfort if the cyst is large and tender.

For patients who are taking blood thinning medications (anticoagulants), FNA can be safely used to obtain cells to help diagnose a lesion without them having to stop taking the medication, as may be necessary with other more invasive procedures, such as core biopsy.

Why would my doctor refer me to have this procedure?

If your doctor feels a lump in your breast during a clinical examination and they think that the lump might be a simple cyst, they may refer you for an ultrasound examination, immediately followed by an FNA at the same visit. The aspiration of the cyst will give an immediate result to your doctor about the nature of the lump, relieve any pain and/or anxiety created by the lump.

FNA may be chosen as the first diagnostic test for a young woman when a new lump is felt. If the lump is thought to be benign (non-cancerous), an FNA may be required to confirm the diagnosis. FNA is preferred to a core biopsy, as it is a less invasive diagnostic procedure.

How do I prepare for a breast FNA?

There is no need for special preparation before a breast FNA. It can be done immediately after you have had a medical examination or following any imaging (such as a mammogram and/or ultrasound) your own doctor may have organised to find out the cause of the lesion.

Breast FNA can be uncomfortable and sometimes painful, and you may wish to ask a friend or a relative to attend the appointment with you if you think you will need some support before, during or after the procedure. Wear a comfortable two-piece outfit, as you will need to have the upper body undressed for the breast FNA.

What happens during a breast FNA?

The radiologist or other doctor (breast physician, breast surgeon, pathologist) carrying out the breast FNA will decide whether they need to use ultrasound to locate and guide the placement of the needle into the lesion. If the doctor can feel the lesion, it is said to be “palpable” and the FNA can be carried out under clinical manual guidance without using ultrasound imaging.

If the lesion is solid, a local anaesthetic injection is recommended for FNA, as they usually require a number of aspirations to remove sufficient cells for an accurate diagnosis. Lumps that contain only fluid may not require a local anaesthetic.

Ultrasound guidance

You will be lying on your back on the examination bed in the ultrasound room, the upper body undressed, with one arm above your head on a pillow in a comfortable position. Sterile gel will be put on your breast and the ultrasound transducer or probe (a smooth, hand-held device) will be slowly moved across the breast to show and identify the lesion on the ultrasound screen. Your breast will be cleaned with an antiseptic liquid, and the needle placed through the skin and into the lesion guided by the ultrasound images.

When the needle is inserted into the lesion, the doctor will move the needle forward and backward several times to collect cells. Two or three separate samples are usually taken in this way to ensure a good sample has been obtained. If the lesion is a simple cyst, the doctor will aspirate the fluid from the cyst until it collapses.

Clinical guidance

FNA under clinical guidance is the same procedure as above, but the doctor will use their hands rather than ultrasound to locate the lesion and to guide the needle into the lesion.

Are there any after effects of a breast FNA?

Any pain after FNA can be relieved with non-prescription analgesics, such as paracetamol. You should not take aspirin, because this thins the blood and may increase the risk of bleeding and bruising.

Minimal bleeding or bruising can appear after the procedure, especially if you are taking anticoagulant medication, aspirin or fish oil. This can be minimised by good compression and the application of an icepack on the skin at the site of the FNA.

Breast FNA does not leave a scar on the skin and there is a low risk of infection.

How long does a breast FNA take?

Breast FNA is a quick test, which takes 10–20 seconds for each sample, and this procedure may be repeated several times until the radiologist or other specialist doctor is confident that they have adequate samples for examination. The FNA procedure will generally take around 20–30 minutes.

What are the risks of a breast FNA?

The risks of a breast FNA are rare and minimal, and can include:

  •  Minimal bleeding and bruising, especially for those taking anticoagulation or anti-platelet medication, aspirin and fish oil.
  • Risk of infection is rare. Breast FNA is a clean and sterile procedure, which uses skin antiseptic and disposable one-use needles.
  • Breast implant perforation can happen if the lesion is close to the implant, but is a rare complication when using ultrasound guidance.
  • Pneumothorax (perforation of the lung covering by the needle causing lung collapse).
  • If the lesion is found to be cancer, there is a very small risk of displacement (“seeding” or implantation) of tumour cells along the tract or path of the needle as it is withdrawn from the breast. This is extremely rare.

Breast FNA is not 100% accurate. Cancer may not be definitely ruled out, even when there are no cancer cells found in the samples of tissue removed from your breast. The results must always be interpreted by the doctors caring for you in the context of their medical examination, findings of your breast imaging (mammogram and/or ultrasound) and the pathology results of the tissue (cells) or fluid sample. This is called the “triple test”.

What are the benefits of a breast FNA?

Breast FNA is a quick and simple procedure to investigate a breast lesion.

There are few complications in having an FNA and few cases where it is not appropriate due to a pre-existing medical or physical condition. Breast FNA can be used when other needle biopsy procedures are not possible; for example, if you are using anticoagulant medication, have an allergy to anaesthetic or have a breast implant.

Who does the breast FNA?

Breast FNA should be carried out by specialist doctors experienced in breast needle biopsy procedures after careful medical examination and imaging tests, such as mammogram or ultrasound, as part of the “triple test” to ensure FNA is appropriate. Ultrasound imaging is carried out by a doctor or a trained sonographer who will help the doctor during the procedure.

Where is a breast FNA done?

Breast FNA with or without the use of ultrasound is carried out in a public or private hospital, radiology practice, a public or private specialist breast clinic, at a BreastScreen assessment clinic, or a surgeon, pathology laboratory or doctors’ rooms equipped with ultrasound.

When can I expect the results of my breast FNA?

Tests of the fluid or tissue sample will need to be carried out in a pathology laboratory to confirm the diagnosis and are usually available within a few days. These results, together with the results of medical and imaging examinations, are reviewed by the doctors and a report is written for your referring doctor. Usually, you can obtain the final results of the breast FNA from your own doctor within a week

Useful websites about breast FNA:

A reference book: Breast fine needle aspiration cytology and core biopsy: a guide for practice:

Diagnostic Imaging Pathways –

*The author has no conflict of interest with this topic.

Page last modified on 7/12/2018.

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