Figure 1. Approach to evaluation of thyroid nodules. Evaluation always includes measurement of thyroid function tests, including thyroid stimulating hormone (TSH), and thyroid ultrasound. If hyperthyroidism is present, a thyroid uptake to exclude an autonomous functioning nodule (i.e. hyperfunctioning thyroid follicular tissue producing thyroid hormone excess). Cold nodules refer to nodules without autonomous production of thyroid hormone. Systems developed for malignancy risk stratification of thyroid nodules on ultrasound include the 2015 American Thyroid Association guidelines (ATA) and the American College of Radiology (ACR-TIRADS). Thyroid fine needle aspiration (FNA) biopsy should be considered for nodules with intermediate or high risk of malignancy based upon size and patient specific factors.