Table 2: European thyroid imaging reporting and data system categories^21,34.

EU-TIRADS categories	Definition	US features	Risk of malignancy (%)
1	Normal	No nodule	NA
2	Benign	Pure cyst, entirely spongiform	0
3	Mildly suspicious	Ovoid, smooth isoechoic/hyperechoic	2–4
4	Moderately suspicious	Ovoid, smooth and mildly hypoechoic	6–17
5	Highly suspicious	One of the following features: Irregular shape Irregular margins Microcalcifications Marked hypoechogenicity (and solid)	26–87

EU-TIRADS = European thyroid imaging reporting and data system; NA = not applicable; US = ultrasound.