Fine Needle Aspiration Biopsy of Thyroid Nodules
Douglas S. Ross, MD
Co-director, Thyroid Associates, Massachussetts General Hospital, Boston
The procedure described by Dr. Randall Gaz (below) is for a "core needle" or "cutting needle" biopsy. This procedure is frequently done in an Outpatient Surgical area to provide for maximum safety.
An alternative method, used in the majority of thyroid biopsies, is a fine needle aspiration technique, which is even simpler than the procedure described by Dr. Gas. The needle utilized for this procedure is quite small, even smaller than the standard needles used to sample blood. The procedure is done in a physician's office and no advanced preparation is needed. Many patients will have a needle aspirate at the time of their initial visit. Bruising may be minimized if aspirin- and ibuprofen-containing medications are avoided prior to the procedure. However, use of these medications is not a contraindication for a fine needle aspiration. Unless you wear a turtleneck, it is not even necessary to change to a hospital gown.
The actual procedure is similar to that of a core needle biopsy. After cleaning the skin over the nodule, a local anesthetic is used to numb the skin. A tiny needle is then inserted into the nodule for 10 to 60 seconds to obtain thyroid tissue for microscopic examination. This "biopsy" may be repeated 3 to 6 times. The entire procedure usually takes less than 20 minutes. It is advisable to apply pressure to the area for about 30 minutes after the biopsy to minimize bruising and swelling. A bandaid placed over the nodule may be removed after a few hours. Most patients can return to work 30 minutes after the procedure. Vigorous physical activity should be avoided for 24 hours.
Both types of thyroid biopsies are relatively non-traumatic and well-tolerated. When appropriate, the fine needle aspiration procedure is less involved, and most patients will initially have a fine needle aspirate. There are two reasons why your physician might recommend one procedure over the other. First and most important is the availability of expertise both in performing and interpreting the biopsy.
For example, if your community does not have someone trained to do fine needle aspirations, or does not have expert cytopathologists who are able to interpret the samples made from the fine needle aspirates, then your physician may recommend that you have a core needle biopsy done by a surgeon. Second, certain types of aspirates from thyroid nodules are difficult to interpret even with expert cytopathologists. If your physician suspects that your nodule will be one of the difficult ones to diagnose, he or she may recommend a core needle biopsy to increase the chance that a definite answer would be obtained with one procedure.
Even in the best hands, approximately 10% of fine needle aspirates are non-diagnostic. This means that too little material was obtained, or the material obtained does not allow the cytopathologist to make a diagnosis. In that instance, your physician might suggest a repeat aspirate, or alternatively recommend a core needle biopsy.
(Adapted from The Bridge, Vol.8, No.1)
Instructions for Patients Undergoing Core Needle Biopsy
Randall D. Gaz, MD
Assistant Professor of Surgery, Harvard Medical School
Massachusetts General Hospital
Has your physician recommended that you have a thyroid needle biopsy? If so, the following sample of the instructions that one physician provides for patients will give you a picture of what is involved.
Copyright © 1993 Thyroid Foundation of Canada/La Fondation canadienne de la Thyroïde.
Adapted from The Bridge, Vol.7, No.4, and Vol. 8, No. 11.
Reprinted from thyrobulletin, Vol. 14, No. 4, 1993.
To order a reprint ($2 P&H) contact the National Office or your local chapter.