In thyroid biopsy, a tissue sample is removed from the thyroid gland—which is located in the neck—for microscopic examination. Several techniques may be used, including fine needle aspiration biopsy, which uses a long, thin needle to withdraw (aspirate) a specimen, and open biopsy, which accesses the thyroid surgically through a small incision.
Purpose of the Thyroid Biopsy
- To locate a thyroid growth and determine if it is benign or malignant (cancerous)
Who Performs Thyroid Biopsy
- Needle biopsy is conducted by a physician.
- Open biopsy is performed by a surgeon and surgical team.
Special Concerns about Thyroid Biopsy
- Open biopsy may require general anesthesia, but is sometimes done with a local anesthetic injection. Performed less frequently than needle biopsy, it is generally done in cases where a larger piece of tissue is needed to confirm a diagnosis, or when complete removal of the thyroid is likely to be necessary.
- Thyroid biopsy should be done with caution in people with bleeding disorders.
Before the Thyroid Biopsy
- Tell your doctor if you regularly take anticoagulants or nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, or naproxen). You will be instructed to discontinue them for some time before the test. Also mention any other medications, herbs, or supplements that you take.
- Do not eat or drink anything for 12 hours before an open biopsy. No fasting is necessary before a needle biopsy.
- For general anesthesia, an intravenous (IV) needle or catheter is inserted into a vein in your arm and the medication is administered. In some cases, a thin tube attached to a breathing machine will be inserted through your mouth and into your windpipe to ensure you breathe properly during the procedure.
What You Experience during Thyroid Biopsy
Fine needle aspiration biopsy:
- You will lie on your back on an examining table with a pillow placed under your shoulder blades.
- The skin at the needle insertion site is cleansed with an antiseptic, and a local anesthetic is injected to numb the area. This injection may cause mild discomfort. Do not swallow as the anesthetic is being administered.
- The doctor inserts a thin needle through the skin into the thyroid, and withdraws a thin column of cells. You may feel pressure as the needle is inserted.
- Additional samples may be obtained.
- Pressure is placed on the needle insertion site until bleeding has stopped, and a small bandage is applied.
- The procedure takes about 10 to 30 minutes.
- You are positioned on your back on an operating table.
- If the procedure does not require general anesthesia, the skin on your neck will be cleansed with an antiseptic, and a local anesthetic is injected to numb the area. This injection may cause mild discomfort.
- An incision is made in your neck.
- A piece of tissue from a thyroid mass is removed with surgical instruments. The specimen may be sent for immediate microscopic inspection via frozen section; if malignant cells are detected, surgery is performed at once to excise the entire gland.
- The incision is stitched closed.
- The length of this procedure may vary widely, depending on whether general or local anesthesia is used.
Risks and Complications
- The most common complications after needle biopsy are swelling or discoloration due to collection of blood under the skin (hematoma) at the needle insertion site (which may cause discomfort, but is harmless) and temporary difficulty swallowing.
- Serious complications, such as inadvertent puncture of other structures in the neck or infection, are rare.
- Open thyroid biopsy using a general anesthetic carries all the risks associated with general anesthesia.
After the Thyroid Biopsy
- No recovery time is usually needed after a fine needle biopsy. After an open biopsy, you will remain in a recovery room for several hours. During this time, your vital signs will be monitored and you will be observed for any signs of complications.
- You may feel more comfortable in a semisitting position with your head partially raised and supported. To avoid straining the biopsy site, you should place both hands behind your neck for support as you sit up.
- You may be given pain-relieving medication such as acetaminophen to allay any discomfort around the biopsy site.
- You may return home. If you received general anesthesia, arrange for someone else to drive you.
- Keep the biopsy site clean and dry. You may shower and wet your neck the day after the procedure.
- For swelling and discomfort resulting from a hematoma after a fine needle biopsy, apply ice initially; after 24 hours, use warm, moist compresses to help dissolve the clotted blood.
- Inform your doctor immediately if you develop persistent bleeding, excessive neck swelling, or unusual pain at the biopsy site; difficulty breathing or swallowing; or signs of infection (such as fever, headache, dizziness, chills, or malaise).
Results of Thyroid Biopsy
- Tissue samples are sent to a pathology laboratory and examined under a microscope for abnormal cells. Possible findings include Hashimoto‘s disease (inflammation caused by immune cells that mistakenly attack thyroid tissue), benign tumor, and cancer.
- This test usually provides a definitive diagnosis. Your doctor will recommend appropriate medical or surgical treatment.
- In rare cases, the cells obtained by a fine needle biopsy are insufficient to make a diagnosis. The procedure may need to be repeated, or an open biopsy may be required.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media