Fine-Needle Aspiration (FNA)

What is fine-needle aspiration?

Fine-needle aspiration (FNA) is a procedure healthcare providers use to get a cell sample from a suspicious lump or an abnormal area of your body. It’s also called a fine-needle biopsy. FNA involves using a thin needle and a syringe to pull out cells, tissue and fluids.

Your healthcare provider then sends the sample to a cytology lab. There, a cytotechnologist screens the cells, and a specialist called a pathologist examines them for analysis. Both providers use the study of cytology to examine the cells.

FNA is the least invasive (least damaging to your body) type of biopsy, but it has limits.

What’s the difference between a core biopsy and fine-needle aspiration?

A core biopsy and fine needle aspiration are both types of needle biopsies.

The needle for a core needle biopsy is wider than that used for FNA. A core biopsy gathers more tissue that can provide more information about the suspicious area than FNA can.

While FNA just involves a thin needle, a core biopsy sometimes requires a small incision to insert a spring-loaded biopsy needle.

Providers most commonly use core biopsies for breast biopsies. They use FNAs for several areas of your body.

What is fine-needle aspiration used for?

Fine-needle aspirations have two main purposes: diagnostic and therapeutic.

Healthcare providers may also use FNAs to help guide treatment in cases where cancer has spread from the original tumor site (metastatic cancer). Pathologists can look for genetic or molecular markers in the cell samples that show if the cancer will respond better to certain cancer treatments.

Diagnostic fine-needle aspiration

Healthcare providers can use fine-needle aspiration (fine-needle biopsy) in any situation where a tissue or fluid sample would help with diagnosis. A pathologist looks at the collected cells under a microscope to determine their type and characteristics.

FNAs are one of several types of biopsies. Your provider may choose FNA or a different kind of biopsy, like excisional or incisional, depending on your unique situation.

Fine-needle biopsies may be necessary to assess a suspicious lump or mass. They can help diagnose:

• Cancer.
• Bacterial infections, like bursitis or septic arthritis.
• Noncancerous masses, like cysts, fibroadenomas or lipomas.

Providers can use FNA on almost any region of your body. But providers most commonly use it to biopsy newly identified masses in your:

• Breast, like breast cysts.
• Thyroid, like thyroid nodules.
• Lymph nodes.
• Skin.

With the help of imaging guidance, like endoscopic ultrasound and computed tomography (CT) scan, providers can use FNA to collect tissue from deeper areas of your body, such as your:

• Pancreas.
• Gastrointestinal (GI) tract.
• Esophagus.
• Trachea.
• Lungs.
• Mediastinum (the space in your chest that holds important organs, like your heart).

Therapeutic fine-needle aspiration

Providers sometimes use FNAs to remove fluid from masses to help treat them, like:

• Abscesses (buildup of pus).
• Cysts (fluid-filled sacs).
• Seromas (abnormal buildups of fluid that are common after breast cancer surgery and plastic surgery).

They may use this technique instead of the standard incision and drainage approach in cosmetically sensitive areas, like your breast. However, FNAs can potentially spread infections, so providers can’t use them in all cases.

How do I prepare for a fine-needle aspiration?

You usually don’t have to do anything special to prepare for fine-needle aspiration. In any case, your healthcare provider will let you know what to expect and how to prepare.

What should I expect during a fine-needle aspiration procedure?

You’ll likely have an FNA in your healthcare provider’s office or a hospital as an outpatient (meaning you’re not staying overnight).

The process can vary based on which part of your body your provider is getting a sample from. But you can generally expect the following during a fine-needle aspiration:

• You’ll lie or sit on a medical table.
• Your provider will sanitize the area where they’ll insert the needle.
• Your provider may inject a local anesthetic to numb the area where you’ll receive the FNA. You may still feel a pinch or some discomfort as the needle enters your skin.
• If your provider is accessing an area deep in your body, they’ll use imaging guidance to guide the direction and location of the needle. Imaging examples include an ultrasound, CT scan or mammogram.
• Your provider will insert the needle into the targeted area. They’ll use a syringe to pull out cells, tissues or fluid.
• Your provider may need to test more than one area or get more than one sample. If this is the case, they’ll use a different needle and syringe for each one.
• Once they finish the procedure, they’ll put a bandage over the site.

What happens after a fine-needle aspiration procedure?

Your provider will send the sample(s) to a laboratory where a pathologist will analyze it. They’ll look at the cells under a microscope and may perform other tests on the sample. The pathologist will put together a report of the findings and send it to your provider to share with you.

What are the risks of fine-needle aspiration?

It’s common to have some soreness and bruising at the injection site. These are usually minor and go away within a couple of days.

Complications of fine-needle aspiration are relatively rare but can include:

• Bleeding. People with blood clotting disorders and/or who take anticoagulants are most at risk.
• Bacterial infection.
• Damage to surrounding structures.
• Fistula (an abnormal connection between two body tissues, such as an organ or blood vessel and another structure).

What type of results do you get from fine-needle aspiration?

There are several possible results you could get from a fine-needle aspiration. Analysis of the sample may show:

• No evidence of abnormal cells.
• A mix of abnormal and normal cells. You may need other types of testing to confirm the diagnosis.
• Precancerous cells.
• Cancerous cells.
• Evidence of a bacterial infection.

Sometimes, the laboratory may ask for additional samples to make a more accurate report. In any case, your healthcare provider will explain the report to you. Together, you’ll decide the next steps.

When should I call my doctor?

Contact your healthcare provider if you develop any symptoms of an infection, like a fever or pus or redness at the injection site. If your lump or bump changes in an unexpected way after the FNA, talk to your provider.

A note from Cleveland Clinic

Finding or learning that you have a suspicious mass in your body can be stressful. The good news is that a biopsy, such as fine-needle aspiration, is the best way to know what the mass is. If you have any questions or concerns about a fine-needle aspiration procedure, don’t hesitate to talk to your healthcare provider. They’re available to help and support you.