Thyroid nodules are very common. Most of them are benign non-secerning incidentally found nodules - thyroid incidentalomas. Ultrasound (US) is an essential initial diagnostic tool in thyroid nodules management. Based on the US character, thyroid nodules should be classified to one of the US risk categories (TIRADS - Thyroid Imaging Reporting and Data System). Based on the US risk category and size, some nodules should be referred to fine needle aspiration with cytological evaluation of the sample (FNAC), some should be followed just by US, and some require no follow-up. Further management depends on the FNAC (Bethesda category) and US risk category. In most nodules (Bethesda category II, repeatedly Bethesda category I, some of the nodules of Bethesda category III), just defensive management is recommended (US and/or clinical follow-up, or no follow-up). Usually, only few cases require diagnostic (Bethesda categories III, IV and V) or therapeutic (Bethesda V and VI) surgery. In decision-making of management of nodules Bethesda category III and V, molecular testing for mutations associated with thyroid cancer and serum calcitonin could be useful.
Keywords: Bethesda classification; TIRADS; fine needle aspiration biopsy; molecular testing; thyroid cancer; thyroid nodule; ultrasound.