Table 3.
The frequency and risk of malignancy of thyroid nodules according to internal content and the presence of suspicious ultrasound (US) featuresa)
| US feature | Overall (n=1,000) | Benign nodule (n=883) | Malignant nodule (n=117) | Malignancy risk (%) | P-valueb) |
|---|---|---|---|---|---|
| Suspicious US features (+) | 144 (14.4) | 92 (10.4) | 52 (44.4) | 36.1 | <0.001 |
| Purely solid | 99 (68.6) | 49 (53.3) | 50 (96.2) | 50.5 | <0.001 |
| Minimally cystic | 6 (4.2) | 6 (6.5) | 0 | 0.0 | 0.087 |
| Partially cystic | 39 (27.1) | 37 (40.2) | 2 (3.8) | 5.1 | <0.001 |
| Suspicious US features (-) | 856 (85.6) | 791 (89.6) | 65 (55.6) | 7.6 | 0.003 |
| Purely solid | 631 (73.7) | 573 (72.4) | 58 (89.2) | 9.2 | 0.425 |
| Minimally cystic | 55 (6.4) | 53 (6.7) | 2 (3.1) | 3.6 | 0.011 |
| Partially cystic | 170 (19.9) | 165 (20.9) | 5 (7.7) | 2.9 | <0.001 |
Values are presented as number (%).
a)
Spiculated/microlobulated margins, nonparallel orientation (taller-than-wide shape), and microcalcification.
b)
The chi-square test or Fisher exact test was used to evaluate associations between each category of internal content, the presence of suspicious US features, and the final diagnosis.