Breast Fine Needle Aspiration (FNA)

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

What is a breast FNA?

Breast FNA is a fine needle biopsy of a breast lesion, which is usually performed under clinical or US guidance:

•  To aspirate fluid from a cystic lesion. The diagnosis is immediate in this case, as the cyst often collapses and completely disappears after aspiration
• To remove cells from a solid lesion for cytological diagnosis.

A limitation if FNA is that the cytologist can only tell if the cells removed by aspiration are normal/benign, or abnormal, atypical or malignant. If a more accurate pathological diagnosis is required, then a breast core biopsy (see InsideRadiology: Breast Core Biopsy) can be carried out to retrieve a larger piece of tissue. This is particularly important in the differentiation between a carcinoma in situ (LCIS/DCIS) from an invasive carcinoma (ILC/IDC), which will impact on the surgical management.

All FNA cytological results should be reviewed and discussed with the clinician, pathologist and radiologist to correlate the “triple test” of clinical, radiological (mammograms and ultrasound) and pathological findings. Once agreement is made between the medical disciplines as to the nature of the lesion, recommendations for management and prognostic information are sent to the referring clinician.

What are the generally accepted indications for a breast FNA?

The indications for breast FNA, which are generally accepted, are the following:

• Aspiration of a symptomatic breast cyst.
• Aspiration of an atypical cyst after ultrasound examination for diagnostic purposes.
• Aspiration and drainage of an abscess.
• Sampling of a new palpable mass as the first diagnostic approach in a young woman to confirm the benign nature of the lesion (for example a fibroadenoma) and to exclude malignancy.
• Sampling of an indeterminate or suspicious lesion clinically felt or seen under ultrasound examination in the first instance when the patient is taking anticoagulation medication.

In the presence of known breast cancer, FNA is also used for sampling an enlarged axillary lymph node to differentiate between reactive or metastatic changes.

What are the prerequisites for having a breast FNA done?

In symptomatic women, a careful preliminary clinical examination and imaging investigation (ultrasound and/or mammograms) is necessary before a breast FNA. Initial ultrasound examination alone is recommended for young and pregnant women. For older symptomatic or asymptomatic women, complete bilateral mammogram work-up and, if necessary, ultrasound are required before any breast FNA is carried out. There is no need to stop medication (e.g. aspirin or anticoagulant medication) before a breast FNA.

It is important for the referring doctor to provide all relevant information on the radiology and pathology request forms including:

• clinical findings, nature and duration of the symptoms;
• exact location of the lesion;
• personal and family history of breast cancer;
• presence of breast implant(s);
• anticoagulant medication;
• use of HRT;
• previous radiotherapy/chemotherapy.

What are the absolute contraindications for a breast FNA?

There are no absolute contraindications for breast FNA.

What are the relative contraindications for a breast FNA?

Needle phobia or inability to cooperate (due to dementia, mental or physical disability) can make the procedure technically difficult or impossible.

Breast FNA is more difficult in the presence of a breast implant. There is a minimal risk of damaging the implant, depending of the location of the breast lesion.

Anticoagulant medications are not contraindicated for a breast FNA, but the specialist doctor who will carry out the test needs to be aware of any anticoagulants, as more compression will be required after the FNA to avoid a hematoma.

What are the adverse effects of a breast FNA?

Minimal bleeding and bruising, and rarely, a hematoma may follow the procedure, especially if the patient is taking anticoagulants. Good compression after the procedure is usually enough to avoid any significant bleeding.

There is minimal risk of infection.

Breast pain after FNA is uncommon and can be relieved by simple analgesics, such as paracetamol (avoid NSAIDS).

Pneumothorax is an extremely rare, but serious, complication that is more frequent if the lesion is deeply located in a small breast and the examination has not been carried out using appropriate imaging guidance.

Breast implant perforation can happen, but is a rare complication of a breast FNA.

Epithelium displacement and tumour cell dissemination along the needle tract may occur after any needle biopsy, but are more common with the larger core needle biopsy than with FNA. However, the clinical significance and long-term relevance implication of this rare complication is not actually known.

Is there any specific post procedural care required following a breast FNA?

No special care is required after a breast FNA. The breast will usually be dressed with a bandage and the patient be given an icepack to cover her breast to stop the bruising. Paracetamol, but not aspirin, can be taken as pain relief after the FNA.

Are there alternative imaging tests, interventions or surgical procedures to a breast FNA?

Some breast lesions are typical on mammograms (calcified fibroadenoma) or ultrasound examination (cyst), and don’t need to be aspirated or biopsied if they are not symptomatic.

Breast core biopsy is recommended:

a) In the presence of inconclusive or non-diagnostic breast FNA. This can happen due to sampling error, inadequate specimen, the nature of the lesion (fibrotic lesion e.g. fibroadenoma, microcalcifications) or inadvertent human error.

b) To distinguish between carcinoma in situ (DCIS/LCIS) and invasive carcinoma (IDC/ILC).

c) To provide a diagnosis in a new indeterminate or suspicious breast lesion, or in areas of suspicious calcification.

Other imaging technologies (e.g. PET, MRI or CT) can help in the description of the lesion, its behaviour or for following up its evolution. However, these will never provide the definitive diagnosis required to reassure the patient or for planning surgical management. Breast MRI may be helpful if other imaging results are normal, for assessing the extent of unilateral breast cancer or for excluding contralateral breast cancers (see InsideRadiology: Breast MRI).

Useful websites about breast FNA:

A reference book: Breast fine needle aspiration cytology and core biopsy: a guide for practice:
canceraustralia.gov.au/publications-resources/cancer-australia-publications/breast-fine-needle-aspiration-cytology-and-core

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

Page last modified on 7/12/2018.