Thyroid Fine Needle Aspiration (FNA)

Asian Mother and DaughterThe most common method for evaluation of a suspicious thyroid nodule is a technique known as fine needle aspiration, or FNA. In an FNA a very fine thin needle is inserted into the thyroid, and aspirates (or "suctions") cells and/or fluid from a thyroid nodule or mass into the needle. The sample obtained can then be evaluated for the presence of cancerous cells.

How Does FNA Differ From Needle Core Biopsy?

In a needle core biopsy a thicker large needle is used to obtain a "core" tissue sample for analysis, and the larger sample than can be recut for smaller samples that can be sent out for further analysis. Needle biopsies are typically done using local anesthesia, and these procedures have slightly greater risk of bleeding associated with them, so they are more often done by a surgeon in outpatient or ambulatory surgical facilities.

If an HMO or community does not have practitioners with expertise in performing FNA, or there are not cyopathologists available to do the unique form of interpretation needed for FNA results, patients are likelier to have a core needle biopsy, as this procedure, while more invasive for patients requires less skill to obtain a valid sample, and less skill for pathologists to reads and interpret.

Who Should Perform an FNA?

Typically, FNAs are done by endocrinologists, cytopathologists or surgeons. The cells are studied and assessed by a cytopathologist.

Make sure that the practitioner has extensive experience in doing fine needle aspirations. Ask how many aspirations the practitioner does each month, and ask their "unsatisfactory" or "inclusive specimens rate. Don’t always assume and endocrinologist is particularly skilled in this technique – he or she may not regularly perform this procedure.

The rate of non-diagnostic or unsatisfactory specimens – samples that cannot be used for laboratory assessment, and must be redone – can be high for some less experienced practitioners. The average can run from 4% to 14%. Dr. Sheffer, whose practice focuses on thyroid and breast aspirations, and who aspirates approximately 40 thyroids each month has a "non-diagnostic rate is less than 0.4 percent.


What is an Ultrasound-Guided FNA?

When a nodule is palpable-meaning you can feel it with your hand – most practitioners don’t need to use ultrasound to guide the FNA process.

Some nodules are very low lying or can only be felt when you are swallowing, or can’t be felt but were picked up by ultrasound, cat scan or MRI. In these cases a practitioner may use ultrasound to ensure that the FNA is accurately performed.

Is FNA Risky?

Thyroid FNA is generally considered safe, and almost never results in any complications.

What Can You Expect During Your FNA?

You may have your test sitting up but many practitioners will begin by having you lie down on the examining table. You’ll be asked not to swallow, talk or move while the aspirations are taking place.

The needle is fairly small and fine. Some practitioners use a needle with a handle. according to Dr. Sheffer these types of needles – sometimes known as a syringe pistol – are preferable. The handle allows the practitioner to leave one hand free to feel the neck and nodule and ensure that the needle doesn’t move around, but rather, is guided right into the nodule to be tested. With a handle less needle, many practitioners have to use both hands to insert the needle which can be a factor for error as the pathologist may not be able to accurately aim the needle into the nodule without a free hand to guide it.

The entire procedure shouldn’t take more than ten to twenty minutes. Most practitioners perform two to four aspirations on every nodule of concern. At Community Radiology NY a minimum of two samples from the center bottom and top of the lump and sometimes several more depending on her judgment as to the quality of the samples.
Many practitioners advise that you apply pressure to the area for approximately 20 minutes after the aspiration in order to minimize bruising or swelling.

How Will It Feel Afterwards?

You might have slight pain with some swelling and bruising at the injection locations and possibly slight discomfort in swallowing. Ask your doctor about recommendations regarding post FNA pain medication – many recommend taking acetaminophen or ibuprofen as directed to minimize any residual discomfort.

Can You Go Back To Work?

Most people are comfortable enough to go back to work the same day or the next day after having an FNA.

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