Thyroid Nodule Evaluation
How are thyroid nodules evaluated?
The main concern in the work up of a thyroid nodule is whether the nodule is caused by a benign or malignant process. There is currently no blood or imaging testing that will definitively diagnose if a thyroid nodule is thyroid cancer. Instead, your endocrinologist at Houston Thyroid and Endocrine will follow a set of diagnostic testing tailored to each individual patient’s clinical history.
The first test that should be done to evaluate a person with a thyroid nodule is a blood test for Thyroid Stimulating Hormone (TSH). This testing will help determine if the thyroid gland is overactive, underactive, or normal in it functional capability. Please refer to the Hyperthyroidism (low TSH) and Hypothyroidism (high TSH) sections of the website to review those conditions.
If you have a thyroid nodule that needs evaluation, contact our thyroid nodule coordinator. Visit our Thyroid Nodule Clinic
If the patient does not have hyperthyroidism then the next diagnostic testing is with a thyroid ultrasound. Similar to some animal species like dolphins and whales, an ultrasound machine creates a visual image based on receiving reflected sound waves. Thyroid ultrasonography is a painless test that the endocrinologists perform in their office. The patient lies on their back, a pillow is placed under the shoulders and upper back to allow the head to tilt backwards. A gel that allows the transmission of sound is applied over the area of the thyroid on the neck. The ultrasound probe, which is the size of an electric shaving machine, is moved over the thyroid area of the neck to create the images. The ultrasound will identify discreet thyroid nodules. Depending on the patient’s risk factors for developing thyroid cancer, these nodules can be biopsied in our Fine Needle Aspiration Clinic (FNA). The cytopathology results of your FNA will generally give one of four possible results: malignant, benign, indeterminate, or not enough sample. Often, the FNA will result with give a definitive answer about the type and cause of the nodule. In some cases the test may be inconclusive and further testing may be required. Your endocrinologist will review in great detail what impact these results could have on the management of your thyroid nodule.
Ultrasound image of a nodule in the middle of a the left thyroid lobe
How often should thyroid nodules be evaluated?
It is recommended that all benign thyroid nodules be followed with serial US (ultrasound) examinations 6–18 months after the initial FNA. If nodule size is stable (i.e., no more than a 50% change in volume or <20% increase in at least two nodule dimensions in solid nodules or in the solid portion of mixed cystic–solid nodules, the interval before the next follow-up clinical examination or US may be longer, e.g., every 3–5 years. If there is evidence for nodule growth either by palpation or sonographically (more than a 50% change in volume or a 20% increase in at least two nodule dimensions with a minimal increase of 2 mm in solid nodules or in the solid portion of mixed cystic–solid nodules), the FNA should be repeated, preferably with US guidance