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.
- 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.
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 examination or seen on a thyroid ultrasound test or radioactive thyroid scan.
- Find the cause of a goiter. Symptoms of a goiter include breathing and swallowing problems, paralyzed vocal cords, a feeling of fullness in the neck, and weight loss.
How To Prepare
Tell your doctor if you:
- Take any medicines regularly. Be sure your doctor knows the names and doses of all your medicines.
- Are allergic to any medicines, including anesthetics.
- Have had bleeding problems or take blood-thinners, such as aspirin or warfarin (Coumadin, for example).
Before having a thyroid biopsy, you may need to have blood tests to see whether you have any bleeding problems or blood-clotting disorders.
To prepare for a thyroid biopsy:
- You do not need to do anything before a needle biopsy. You will be asked to undress and put on a hospital gown. You will be awake during the biopsy.
- Do not eat or drink anything for 10 hours before an open biopsy. You will get general anesthesia and be asleep during the biopsy. If you take medicines every day, ask your doctor whether you can take these medicines on the day of the biopsy. You can eat your normal diet after the biopsy.
Just before the test, you will remove your dentures (if you wear them) and all jewelry or metal objects from around your neck and upper body.
Before having a thyroid biopsy, you need to sign a consent form that says you understand the risks of the thyroid biopsy and agree to have the test done. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .
How It Is Done
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. It is important to lie very still during the biopsy. Do not cough or swallow when the needle is in place. A needle biopsy takes about 5 to 10 minutes.
Before the biopsy, you may be given a medicine (sedative) to help you relax. Your doctor cleans the skin over your thyroid gland with a special soap.
Your doctor may use an ultrasound to guide the placement of the needle. He or she will put a thin needle into your thyroid gland and take out a small amount of thyroid tissue and fluid. The tissue is looked at under a microscope.
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. It is done when other tests have not found the cause of your symptoms. An open biopsy takes about an hour.
You may be given a sedative to help you relax. An intravenous (IV) line is inserted in a vein in your arm for medicine and fluids. You will be asleep for the 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 laboratory during the biopsy to see whether it has cancer cells. If cancer cells are present, your doctor may take out more or all of the thyroid gland.
The incision is closed with stitches. A bandage is put over the stitches. Keep the biopsy site covered and dry for 48 hours. A small amount of bleeding from the biopsy site can be expected. Ask your doctor how much drainage to expect. Some people may need to stay in the hospital for one night.
Open biopsy is not as commonly done as needle biopsy.
How It Feels
You may find it uncomfortable to lie still with your head tipped backward.
During a needle biopsy, you may feel a quick sting or pinch in your neck.
The biopsy site may be sore and tender for 1 to 2 days. You can take nonprescription pain medicine, such as acetaminophen, for the discomfort.
You will be asleep and feel nothing during the biopsy. After the biopsy, you may have some nausea and general muscle aches and may feel tired for 1 to 2 days. You also may have a sore throat and sound hoarse. Suck on throat lozenges or gargle with warm salt water to help your sore throat.
The biopsy site may be sore and tender for 3 to 4 days. Your doctor will give you pain medicine for this.
After a thyroid biopsy, you may be more comfortable if you keep your head up on a pillow when you lie down. Support the back of your head and neck with both hands when you sit up to prevent discomfort at the biopsy site.
There is a small chance of problems from a thyroid biopsy, such as infection and bleeding.
Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (such as Coumadin), and other blood-thinning medicines can make bleeding more likely. Your doctor will give you specific instructions on when to call him or her with problems.
After the test
Call your doctor immediately if you have:
- A lot of bleeding through the bandage.
- A hard time swallowing.
- Signs of infection,
- Increased pain, swelling, redness, or warmth around the biopsy site.
- Red streaks spreading from the biopsy site.
- Drainage of pus from the biopsy site.
- Swollen lymph nodes in the neck.
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. 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.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
- If you have bleeding problems or take blood thinners. People with these conditions will get specific instructions from the doctor before the biopsy.
- If you cannot lie still during a needle biopsy. You may need general anesthesia for the biopsy.
What To Think About
- A normal (negative) report on a thyroid biopsy does not mean for sure that the thyroid gland is healthy. It is possible that a problem may have been missed. Many thyroid tumors are small, and the biopsy sample may come from an area of the thyroid that is free from disease. A fine-needle biopsy can have a false-negative result.
- Your doctor may not be able to use a needle biopsy to find out what is causing your symptoms. An open thyroid biopsy may be needed.
- If a thyroid nodule is found and thyroid hormone levels are normal, most doctors recommend a thyroid needle biopsy instead of a radioactive thyroid scan. For more information, see the medical tests Thyroid Scan and Radioactive Iodine Uptake Test.
- If a thyroid nodule is found and high thyroid levels are present, a radioactive iodine uptake (RAIU) test is generally recommended before a thyroid biopsy. Nodules that cause hyperthyroidism are generally noncancerous (benign) and can be treated with medicine or radioactive iodine. For more information, see the medical test Radioactive Iodine Uptake Test.
Other Works Consulted
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
|Author||Bets Davis, MFA|
|Editor||Maria G. Essig, MS, ELS|
|Associate Editor||Terrina Vail|
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||Matthew I. Kim, MD - Endocrinology & Metabolism|
|Last Updated||August 13, 2009|