Table 1 US patterns and estimated risk of malignancy proposed by American Thyroid Association ATA, 2015
Benign - Estimated risk of malignancy < 1% | |
US features: Purely cystic nodules (no solid component) | |
Very low suspicion risk - Estimated risk of malignancy < 3% | |
US features: Spongiform or partially cystic nodules without any of US features defining low-, intermediate- or high-suspicion patterns | |
Low suspicion risk - Estimated risk of malignancy 5–10% | |
US features: Iso- or hyperechoic solid nodule, or partially cystic nodule with eccentric solid areas, without microcalcification, irregular margins, extrathyroidal extension (ETE) or taller-than-wide shape | |
Intermediate suspicion risk - Estimated risk of malignancy 10–20% | |
US features: Hypoechoic solid nodule with smooth margins without microcalcification, ETE or taller-than-wide shape | |
High suspicion risk - Estimated risk of malignancy > 70–90% | |
US features: Solid hypoechoic nodule or solid hypoechoic component of a partially cystic nodule with one or more of the following features: irregular margins (microlobulated, infiltrative), microcalcification, taller-than-wide shape, rim calcifications with small extrusive soft tissue component or ETE |