What is a thyroid fine needle aspiration biopsy?

A fine needle aspiration biopsy of the thyroid is a procedure to remove a small sample of tissue from your thyroid gland. Cells are removed through a small, hollow needle. The sample is sent to the lab for testing.

The thyroid gland is in the front of your neck. It's butterfly shaped, with two lobes connected by a narrow band of tissue. It's an endocrine gland that makes thyroid hormone. This hormone has many functions in your body.

In some cases, hard nodules form inside the gland. You might notice a small bump in your gland area. Most times, the nodules are not dangerous. But in some cases, they can be thyroid cancer. A biopsy takes a sample from the nodule to test for cancer.

Why might I need a thyroid fine needle aspiration biopsy?

You might need the test to see whether your nodule is cancerous. You might have noticed the nodule yourself, or your healthcare provider might have noticed it during an exam or on another test.

Researchers don't know what causes most thyroid nodules. They are very common, though. Thyroid nodules are much more common in women than in men. They tend to grow during pregnancy. Certain problems with the thyroid gland, like Hashimoto thyroiditis, may increase your chances of getting a thyroid nodule. People who have had radiation treatments to their neck as children are also more likely to develop nodules. Your risk of developing thyroid nodules or thyroid cancer is increased if members of your family have already had thyroid and certain other cancers.

Only a small percentage of thyroid nodules turn out to be cancer. It's important to identify a cancerous nodule as soon as possible so that you can start treatment quickly.

Not everyone who has a thyroid nodule needs a fine needle aspiration biopsy. Your healthcare provider may start with an ultrasound or computed tomography (CT) scan of your neck. Sometimes, this gives enough information to know that the nodule isn’t due to cancer. Blood tests of thyroid levels also may provide helpful information. If your healthcare provider can’t tell for sure, you may need a biopsy. Your healthcare provider will also examine your neck for any enlarged lymph nodes. Having an enlarged lymph node makes it more likely that you will need a biopsy.

The procedure is less invasive than open and closed surgical biopsies. These involve larger incisions in your skin. Healthcare providers do these procedures much less often than fine needle aspiration biopsy.

What are the risks of thyroid 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 the thyroid

Because most healthcare providers use ultrasound to guide the procedure, this last complication is rare.

There is also a small risk that the fine needle aspiration biopsy will not show for sure whether the nodule is cancerous. If this happens, you might need a repeat biopsy.

How do I get ready for a thyroid fine needle aspiration biopsy?

There is very little you need to do to prepare for a thyroid fine needle aspiration biopsy. Ask your healthcare provider whether you should stop taking any medicines such as blood thinners before the procedure. You should be able to eat and drink normally before the procedure. You will probably go to an outpatient center to have the procedure. You should be able to go home that same day.

What happens during a thyroid 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, your healthcare provider might inject a local anesthetic to the area before inserting the needle. Because the needle is so small, this is often not necessary.

Your healthcare provider may do the biopsy with the help of an ultrasound machine. This machine uses high-frequency sound waves to provide a live image of the nodule. This enables your healthcare provider to guide the needle to exactly the right spot. It also prevents damage to other structures. A gel-like substance will be applied to your neck, where the ultrasound detector will be used.

After cleaning the area, your provider will insert the thin, fine needle into your thyroid gland. This may hurt a little. The provider will slowly advance the needle into the nodule itself, moving it back and forth several times.

The needle attaches to a syringe that can apply suction and remove some cells from the nodule. After the removal of the needle, these cells will be placed on a slide. Your healthcare provider might repeat this procedure a few times to get different samples from different parts of the nodule. Sometimes the lump will be all or mainly fluid. The fluid can be removed during the biopsy.

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

What happens after a fine needle aspiration biopsy?

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 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 that your healthcare provider gives you.

It may take several days to get your test results. Ask your healthcare provider when you can expect to get your results back.

If your thyroid nodule is not cancer, you might not need any further treatment. Your healthcare provider may want to monitor your nodule, though, and you might need another biopsy in the future. In some cases, your healthcare provider may offer thyroid hormone pills. These can sometimes decrease the likelihood of nodules growing back. Sometimes, your healthcare provider may inject a substance or apply radiofrequencies to shrink the nodule.

You will probably need surgical treatment if your nodule appears cancerous. Luckily, most thyroid cancers are curable.

Sometimes, the lab can't determine for sure whether your nodule is cancer. In this case, your healthcare provider might recommend a repeat biopsy or surgery. Whatever your test results, work with your healthcare provider to develop the best possible treatment plan for you.

Next steps

Before you agree to the test or the procedure, make sure you know:

• The name of the test or procedure

• The reason you are having the test or procedure

• What results to expect and what they mean

• The risks and benefits of the test or procedure

• What the possible side effects or complications are

• When and where you are to have the test or procedure

• Who will do the test or procedure and what that person’s qualifications are

• What would happen if you did not have the test or procedure

• Any alternative tests or procedures to think about

• When and how you will get the results

• Who to call after the test or procedure if you have questions or problems

• How much you will have to pay for the test or procedure