Fine Needle Aspiration Biopsy

What is a fine needle aspiration biopsy (FNA)?

A thyroid fine needle aspiration biopsy is a procedure that removes a small amount of material from your thyroid gland. Cells are removed through a thin syringe needle. The sample is sent to the lab for analysis. 

Why might you need a FNA?

You might need the test to see whether a nodule or growth inside your body is cancerous. We cannot always get an accurate answer with FNA, but the procedure is less invasive than open and closed surgical biopsies. These involve incisions in your skin or the use of much thicker needles, but in certain situations, FNA can give accurate and fast results. 

What are the risks of fine needle aspiration biopsy?

Thyroid fine needle aspiration biopsy is a very safe procedure, but it does carry some slight risks. These include:

• Bleeding at the biopsy site
• Infection
• Damage to the structures near tumour.

Because of the thin size of the needle and using modalities like ultrasound to guide the procedure, this last complication is very rare.

In cases where the FNA cannot give an accurate answer or where the result is conflicting with the clinical or radiological appearance, you might need a repeat biopsy.

How do you prepare for a FNA?

There is very little you need to do to prepare for a fine needle aspiration biopsy. Inform us of any any medicines you are taking, like blood thinners. You should be able to eat and drink normally before the procedure. You might have the procedure in the doctor’s rooms or at the radiology unit. You should be able to go home that same day.

What happens during a fine needle aspiration biopsy?

Some people, like children, might need a medicine to help them relax before the procedure. Most people will not need this, though.

In some cases, the person doing the FNA might inject some local anesthetic to the area before inserting the needle. Because the needle is so thin, this is often not necessary.

We may need to perform the biopsy with the help of an ultrasound machine. This machine uses high-frequency sound waves to provide a real-time image of the nodule. This enables us to guide the needle to exactly the right spot. 

After cleaning the area, your provider will insert the thin needle through the skin into the lump. This may hurt a little. He or she will slowly advance the needle into the nodule itself, then move it back and forth several times to allow cells to enter the needle.

The needle attaches to a syringe that can apply some suction and remove some cells from the nodule. After the removal of the needle, these cells will be placed on a glass slide or special liquid medium. We might have to repeat this procedure a few times to obtain samples from different parts of the nodule or to collect cells for specialized tests like Afirma for the thyroid. Sometimes the lump will consist of mainly fluid (called a cyst). This fluid can often be removed completely with disappearance of the lump.

After the procedure, the cells will be sent to a pathology lab and analyzed for signs of cancer. A small bandage will be placed over the needle insertion site.

What happens after a FNA?

Most people will be able to resume their normal activities right away. You can remove your bandage within a few hours.

The site of the biopsy might be sore or slightly swollen for a day or two after the procedure. You can take over-the-counter pain medicines if you need to. Follow any other specific instructions we might give you.

It may take several days to get your test results from the pathology lab. You may usually enquire about your result after 3 days.

Sometimes, the pathologist cannot determine for sure whether your nodule is cancer. In this case, we might recommend a repeat biopsy or an alternative, more invasive type of biopsy or even surgery. Whatever your test results, we will assist you to develop the best possible treatment plan for you.