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. Your doctor will instruct you if and when you need to stop taking any of the following medicines.
  • Thyroid hormones
  • Antithyroid medicines
  • Medicines that have iodine, such as iodized salt, kelp, cough syrups, multivitamins, or the heart medicine amiodarone (Cordarone, Pacerone)
• Are allergic to any medicines, including anesthetics.
• Have had bleeding problems or take blood-thinners, such as aspirin or warfarin (Coumadin).
• Have had any test using radioactive materials or iodine dye 4 weeks before the thyroid biopsy.
• Are or might be pregnant.
• Are breast-feeding.

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?) .