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Fine Needle Aspiration of the Thyroid Gland

About FNA

An FNA is a common non-surgical, minimally invasive method for evaluating suspicious thyroid nodules. An FNA allows the physician to collect cells from the thyroid nodule and send them to the lab for further analysis. During an FNA, the patient's skin is cleansed and then a small needle is injected into the skin and cells or fluids are suctioned from the thyroid nodule with a syringe. An ultrasound is often used to improve the accuracy of the FNA. This process is repeated 3-5 times in order to obtain adequate cell counts for lab testing and diagnosis.

Preparing for your FNA 

  • Avoid taking ibuprofen (Advil), Motrin, or Aspirin at least 5 days before the procedure.
  • Notify the physician if you are taking blood thinning medicine.
  • Wear a button up shirt instead of one with a high collar.

Post FNA Instructions

You may experience slight swelling and discomfort at the injection site. If this occurs, alternate applying a cold then a warm washcloth for intervals of 10 minutes. You may take Acetaminophen or Tylenol afterwards. You may return to work the same day, but you should avoid strenuous activities for 24 hours.

FNA Results

There are three possible results that come from a fine needle aspiration biopsy. The first is that the biopsy could be completely negative, an indication of benign cells seen by the pathologist. Certainly a benign finding is the best possible outcome. While this does not guarantee that there is no reason for concern, it does reassure us that benign pathology is likely present. In this instance, we would follow the thyroid nodule with serial ultrasound and clinical examination to ensure that the biopsy was correct and that things are not changing in a worrisome way.

thyroid fna chart

thyroid fna chart

A positive biopsy result from a fine needle aspiration indicates either definite cancer cells seen on the biopsy or a suspicion that is high enough to warrant further treatment. This could take the form of a hemithyroidectomy where half of the thyroid is removed. Alternatively, in cases where there is a definite type of cancer seen on the FNA, complete removal of the thyroid may be recommended. These decisions are based on individual circumstances combining both patient factors and elements of the pathology.

For several reasons the FNA could return indeterminate results. There are several instances where this could happen. One of those is in the case of a follicular neoplasm.  This is a particular type of lesion which needs to be biopsied via a surgery. This is because the pathologist cannot tell a benign follicular adenoma from a malignant follicular carcinoma without examining the entire lesion. In other instances, the pathology is indeterminate and a repeat biopsy (FNA) may be indicated.