A thyroid biopsy is a procedure in which a small sample of tissue is removed from the thyroid gland and looked at under a microscope for cancer, infection, or other thyroid problems. The thyroid gland is found in front of the windpipe (trachea), just below the voice box (larynx).
A sample of thyroid tissue can be taken by:
- Fine-needle biopsy. Your doctor puts a thin needle through the skin and into the thyroid gland. Many thyroid specialists like to use a needle biopsy method rather than surgery.
- Core needle biopsy. Your doctor inserts a needle with a special tip and removes a sample of tissue about the size of a grain of rice.
- Open biopsy. Your doctor makes a cut (incision) through the skin to see the thyroid gland. This method is done when other tests have not found the cause of your symptoms.
Open biopsy is not as commonly done as needle biopsy.
Why It Is Done
A thyroid biopsy is done to find the cause of a lump (nodule) found in the thyroid gland. Lumps in the thyroid gland may be found during a physical exam or seen on a thyroid ultrasound test or a radioactive thyroid scan.
How To Prepare
You may have a needle or open biopsy.
- Needle biopsy.
You do not need to do anything to prepare. You will be awake during the biopsy.
- Open biopsy.
- You will get general anesthesia and be asleep during an open biopsy. Follow the instructions exactly about when to stop eating and drinking. If you don't, your procedure may be canceled. If your doctor told you to take your medicines on the day of the procedure, take them with only a sip of water.
Before having a thyroid biopsy, you may need to have blood tests to see whether you have any bleeding problems or blood-clotting disorders.
Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.
If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your test. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.
Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
How It Is Done
Just before the test, you will remove all jewelry or metal objects from around your neck and upper body.
A needle biopsy is done in a hospital, clinic, or your doctor's office. During the test, you will lie on your back with a pillow under your shoulders, your head tipped backward, and your neck extended. This position pushes the thyroid gland forward, making it easier to do the biopsy. Do not cough, talk, or swallow when the needle is in place.
Before the biopsy, you may be given a medicine (sedative) to help you relax. Your doctor will clean the skin over your thyroid gland with a special soap.
Your doctor may use an ultrasound to guide the placement of the needle. Your doctor will put a thin needle into your thyroid gland and take out a small amount of thyroid tissue and fluid. More than one sample is usually taken. The tissue is looked at under a microscope.
A core needle biopsy may be done if the results of the fine needle biopsy are uncertain. A single sample of thyroid tissue and fluid will be taken.
A small bandage is placed over the area where the needle was inserted.
An open biopsy of the thyroid gland is done in an operating room by a surgeon.
You will get general anesthesia and be asleep during an open biopsy.
The skin over your thyroid gland is cleaned with a special soap. A small cut (incision) is made in your neck. A sample of thyroid tissue is taken or your doctor can take out a lump if one is present. Some thyroid tissue may be sent to the lab during the biopsy to see if it has cancer cells. If cancer cells are found, your doctor may take out more or all of the thyroid gland.
The incision is closed with stitches, and a bandage is put over the stitches. Some people may need to stay in the hospital for the night.
How long the test takes
A needle biopsy takes about 5 to 10 minutes. An open biopsy takes about an hour.
How It Feels
If you have a needle biopsy, you may find it uncomfortable to lie still with your head tipped backward. You may feel a quick sting or pinch in your neck. If you have an open biopsy, you will be asleep and feel nothing during the biopsy.
There is a small chance that a thyroid biopsy may cause infection, bleeding, or nerve damage in the thyroid. There is also a small chance that an open thyroid biopsy may cause breathing problems.
Results from a thyroid biopsy are usually available in a few days.
The biopsy shows normal thyroid tissue.
The biopsy sample shows thyroid disease (such as inflammation of the thyroid gland), thyroid cancer, or a noncancerous (benign) tumor.
A thyroid cyst is found at the time of a biopsy. Most cysts of the thyroid gland are not cancerous.