Fine Needle Aspiration (FNA) of Thyroid Nodule

This information explains the fine needle aspiration of thyroid nodules procedure.

FNA Procedure

A fine needle aspiration (FNA) is done to remove cells from a thyroid nodule. These cells can then be examined to see if they have cancer. The FNA can be done in the doctor’s office with a tiny needle. More commonly, it is done at a radiology department or center where an ultrasound can be used to guide the needle.

  • If you have it done at Memorial Sloan Kettering Cancer Center (MSK), your doctor’s office will help arrange this appointment. You may take your medicines and eat a light meal before the FNA. You do not need to stop blood thinning medicines or aspirin before your procedure.
  • If you are having it done at a local radiology center, your doctor will give you a prescription. Please check with them about what instructions they want you to follow before the procedure.

During the FNA you will be lying down. An ultrasound of the neck is usually done first to see the thyroid gland and to locate the nodule. The doctor then inserts a thin needle through the skin in the front of your neck. Cells are withdrawn from the nodule. The needle holder looks large, but the needle itself is very thin. The doctor usually inserts the needle at least twice to gather enough cells from the nodule. If more than one nodule is to be biopsied, more fine needles will be used. In most cases, local anesthesia is not needed.

After the FNA, you may have mild discomfort. You can take extra strength acetaminophen (Extra Strength Tylenol®). If you are not able to take acetaminophen, please let us know. Your doctor can suggest another pain medicine. You may also apply a cold compress if you are still uncomfortable.

After the aspiration, you may also have some mild swelling. You should not be concerned. You may eat and drink as you wish. There are no restrictions.

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FNA Results

The cells taken during the FNA are sent to a lab to be examined. It takes 4 to 5 business days to get the results. Your doctor may discuss the results over the phone or you may need to make an appointment to discuss them in the office.

The types of cells that may be found in your nodule are:

  • Malignant (thyroid cancer) - You will probably need surgery.
  • Benign (not cancer) - Your doctor will tell you how your nodules should be monitored.
  • Suspicious for cancer - Your doctor will tell you what needs to be done.
  • Inconclusive (not able to tell if it is cancer or not). Your doctor will tell you how your nodules should be monitored.
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Call Your Doctor or Nurse If You Develop:

  • Shortness of breath
  • Swelling or redness that seems to be increasing
  • A temperature of 101°F (38.3°C) or higher
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