Table 2.

EU-TIRADS categories and risk of malignancy

Category	US features	Malignancy risk, %
EU-TIRADS 1: normal	No nodules	None
EU-TIRADS 2: benign	Pure cyst Entirely spongiform	$0
EU-TIRADS 3: low risk	Ovoid, smooth isoechoic/hyperechoic No features of high suspicion	2–4
EU-TIRADS 4: intermediate risk	Ovoid, smooth, mildly hypoechoic No features of high suspicion	6–17
EU-TIRADS 5: high risk	At least 1 of the following features of high suspicion:	26–87
	− Irregular shape
	− Irregular margins
	− Microcalcifications
	− Marked hypoechogenicity (and solid)

EU-TIRADS, European Thyroid Imaging Reporting and Data System; US, ultrasound.