Table 1a. Sonographic patterns, estimated risk of malignancy, and fine needle aspiration guidance for thyroid nodules^*.

Sonographic pattern	Ultrasound features	Estimated riskof malignancy, %	FNA size cutoff(largest dimension)
High suspicion	Solid hypoechoid nodule or solid hypoechoic component of a partially cystic nodule with one or more of the following features: irregular margins (infiltrative, microlobulated), microcalcifications, taller than wide shape, rim calcifications with small extrusive soft tissue component, evidence of ETE.	>70–90*1	Recommend FNA at ≥ 1 cm
Intermediate suspicion	Hypoechoic solid nodule with smooth margins without microcalcifications, ETE, or taller than wide shape.	10–20	Recommend FNA at ≥ 1 cm
Low suspicion	Isoechoic or hyperechoid solid nodule, or partially cystic nodule with eccentric solid areas, without microcalcification, irregular margin or ETE, or taller than wide shape.	5–10	Recommend FNA at ≥ 1,5 cm
Very low suspicion	Spongiform or partially cystic nodules without any of the sonographic features described in low, intermediate, or high suspicion patterns.	<3	Consider FNA at ≥ 2 cm Observation without FNA is also a reasonable option
Benign	Purely cystic nodules (no solid component)	<1	No biopsy*2

US-guided FNA is recommended for cervical lymph nodes that are sonographically suspicious for thyroid cancer

^*1The estimate is derived from high volume centers, the overall risk of malignancy may be lower given the interobserver variability in sonography.

^*2Aspiration of the cyst may be considered for symptomatic or cosmetic drainage.

ETE, extrathyroidal extension.

^*according to the American Thyroid Association, 2015 (8)