If you or your medical provider has discovered a thyroid nodule in your neck, this is going to require a specialist’s evaluation. Typically, the workup is multistaged. The first step is a careful patient history including attention to any past head or neck irradiation. This would be done for conditions like cancer of the neck, breast, or lungs. A history of radiation exposure also is a very important risk factor for thyroid cancer. Some patients received radiation treatments for adenoid enlargements or even acne. This is not something that is practiced today, but in older patients these treatments may have been received. Others may have been exposed to radiation from x-rays, or CT scans particularly if they work in radiology. Finally, a family history of thyroid cancer is very important in the evaluation. Other thyroid related diseases such as Cowden syndrome, Multiple Endocrine Neoplasia (MEN type 2), familial polyposis, Carney complex, or Werner syndrome in a close relative are all important information for your doctor to know.
Physical examination during the workup is pretty straightforward and painless. This will focus on enlargements in the neck, looking for not only the thyroid itself but for any enlarged lymph nodes in the area. Typically, a neck ultrasound is going to be the best way to visualize the thyroid and determine the type of nodule that is present. The ultrasound examination is probably the most critical decisionmaking test in evaluation of the thyroid nodule.
Do I need a FNA?
Depending upon the characteristics of the thyroid nodule on ultrasound, it may be elected to proceed with a fine needle aspiration biopsy which would be done under ultrasound guidance. Criteria for FNA have changed in recent years and the American Thyroid Association has specific guidelines available on their website that are categorized by the type of nodule that is seen on ultrasound. An older test, called a thyroid uptake scan uses low dose radioactivity to evaluate the thyroid. This test is typically unnecessary for workup of a thyroid nodule, given better alternatives now available. Ordering uptake scans for nodules was a common practice as it resulted in a nodule being assigned to the “hot nodule” or “cold nodule” category. The thinking was that hot nodules were never cancerous while cold nodules were highly suspicious for cancer. Neither of these assumptions are true! Thankfully, this dated test has been supplanted by the far superior ultrasound-guided FNA. It is quite rare that an uptake scan is needed for routine thyroid nodule evaluation. One caveat- the uptake scan can still be useful in limited cases for the evaluation of hyperthyroidism. More on hyperthyroidism can be found here. But, determining whether a nodule is “hot” or “cold” by uptake scan is not a needed part of thyroid nodule evaluation.
Lab Tests for Evaluating Thyroid Nodules
Initial lab tests should include a thyroid stimulating hormone (TSH measurement). Further blood work may be performed but a TSH is sufficient for initial screening purposes.
It is important to understand that there are no blood tests that can determine the nature of a thyroid nodule! A fine needle aspiration biopsy is the most reliable way to sort out the 85-90% of thyroid nodules that are benign from those that are cancerous. A blood test does not determine the status of a thyroid nodule, but it does give information about the surrounding thyroid and how well that is functioning. While the FNA is the best method for determining whether cancer is present, there are limitations to this technique. Occasionally FNA is not diagnostic and further steps would then be warranted. There is also a middle ground called indeterminant which can require more detailed evaluation which will be described here on this website.