Thyroid nodules are a frequent finding on neck sonography. Most nodules are benign; therefore, many nodules are biopsied to identify the small number that are malignant or require surgery for a definitive diagnosis. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon.
As defined by the American Thyroid Association’s task force on the management of thyroid nodules and differentiated thyroid cancer, a thyroid nodule is a discrete lesion within the thyroid gland that is radiologically distinct from the surrounding thyroid parenchyma.
Differentiated thyroid cancer (DTC) is defined as a carcinoma deriving from the follicular epithelium and retaining basic biological characteristics of healthy thyroid tissue, including expression of the sodium iodide symporter (NIS), the key cellular feature for specific iodine uptake.
Burch and Wartofsky have delineated a point system assessing degrees of dysfunction in various systems (thermoregulatory, central nervous, gastrointestinal, and cardiovascular).