This resource explains what to expect during and after your procedure for a fine needle aspiration (FNA) of your thyroid. An FNA is also called a fine needle biopsy.
About your FNA procedure
The thyroid gland is a small gland in the lower part of the front of your neck. Your thyroid makes hormones that control your metabolism (how your body breaks down food into energy).
A fine needle aspiration (FNA) is a procedure that uses a thin needle to collect cells from a nodule in your thyroid gland. Thyroid nodules are abnormal growths of tissue or fluid. They may or may not be cancer. Your healthcare provider will send the cells taken during your FNA to a lab to be checked for cancer.
Your FNA procedure can be done in your healthcare provider’s office or at a local radiology center. If you’re having your FNA done at MSK, your healthcare provider’s office will help schedule this appointment.
On the day of your procedure:
- Eat a light meal so you don’t feel dizzy and lightheaded (like you might faint). You do not need to follow a special diet.
- Keep taking your medicines as you usually do, unless your healthcare provider gives you different instructions.
- Tell your healthcare provider if you’re taking aspirin or any anticoagulant (blood thinner) medicine. Examples of anticoagulants include warfarin (Coumadin®), dalteparin (Fragmin®), and enoxaparin (Lovenox®). Your healthcare provider may tell you to stop taking your medicine several days before your procedure.
What to expect during your FNA
You’ll be lying down during your FNA procedure. Most often, your healthcare provider will do an ultrasound of your neck first. An ultrasound is an imaging scan that uses sound waves to create pictures of the inside of your body.
Your healthcare provider will use the scan to see your thyroid gland and find the nodule. Then, your healthcare provider will place a thin needle through the skin in the front of your neck. They’ll use the needle to take cells out of the thyroid nodule. They may insert the needle more than once to collect enough cells from the nodule. If your healthcare provider needs cells from more than 1 nodule, they may collect more samples.
Most people don’t need local anesthesia for this procedure. Local anesthesia is a medicine that makes an area of your body numb.
What to expect after your FNA
You may have mild (not bad) discomfort after your FNA. If you do, take acetaminophen (Tylenol®). If you can’t take acetaminophen, tell the healthcare provider who sent you for your FNA. They can suggest another medicine.
You may also have some mild swelling after your FNA. If you do, put a cold compress (such as an ice pack or a cool washcloth) on the area. Do this for 20 minutes to help reduce the swelling. It’s important that you take the cold compress off for at least 20 minutes before you put it back on.
You don’t need to follow any special diet after your procedure. You may eat and drink as you usually do.
If you have your FNA done at MSK, read What to Expect After Your Fine Needle Aspiration at MSK’s Fine Needle Aspiration Biopsy Clinic to learn more.
Getting your FNA results
It can take up to 1 week to get your FNA results. The healthcare provider who sent you for your FNA will call you when your results are ready. They may give you your results over the phone or ask you to come in for an appointment.
The types of cells that may be found in your nodule include:
- Malignant (cancerous) cells. Depending on your FNA results, you may need surgery. If you don’t need surgery, your healthcare provider will talk to you about follow-up care.
- Benign (not cancer) cells. Your healthcare provider will tell you how to monitor (keep track of) your nodule(s).
- Cells that may be cancer. Your healthcare provider will talk to you about next steps.
- Inconclusive (unclear). Your healthcare provider won’t be able to tell if it’s cancer or not. They’ll tell you how to monitor your nodule(s).
When to call your healthcare provider
Call the healthcare provider who sent you for your FNA if you have:
- A fever of 101 °F (38.3 °C) or higher.
- Swelling, warmth, redness, or drainage around your biopsy site that’s getting worse.
If you have trouble breathing, call 911.
If you need to see a healthcare provider right away, go to your local emergency room or to:
MSK’s Urgent Care Center (UCC) at Memorial Hospital (MSK’s main hospital)
425 East 67thStreet (between York and First Avenues)
New York, NY 10065
The UCC is on the 1stfloor.
If you have questions or concerns, contact your healthcare provider. A member of your care team will answer Monday through Friday from to Outside those hours, you can leave a message or talk with another MSK provider. There is always a doctor or nurse on call. If you’re not sure how to reach your healthcare provider, call 212-639-2000.
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