Table 2. Clinical characteristics and US features.
| Parameter | Total | No. of benign lesions | No. of malignant lesions | P value |
|---|---|---|---|---|
| Patients | 1,697 | 957 | 740 | |
| Mean age (years)§ | 49.7±12.2 | 50.3±12.1 | 45.5±11.9 | <0.01 |
| Males§, n (%) | 361 (21.3) | 172 (18.0) | 189 (25.5) | <0.01 |
| Females§, n (%) | 1,336 (78.7) | 785 (82.0) | 551 (74.5) | <0.01 |
| No. of nodules | 2,309 | 1,418 | 891 | |
| Mean size of mass (mm) | 13.1±10.6 | 15.7±12.0 | 9.1±5.9 | <0.01 |
| Distribution location (total) | 2,309 | 1,418 | 891 | <0.01 |
| Upper zone | 483 | 248 | 235 | |
| Middle zone | 884 | 548 | 336 | |
| Lower zone | 887 | 594 | 283 | |
| Isthmus | 65 | 28 | 37 | |
| Composition, n (%) | 2,309 | 1,418 | 891 | <0.01 |
| Solid | 1,817 (78.7) | 934 (65.9) | 883 (99.1) | |
| Predominately solid/cystic | 390 (16.9) | 382 (26.9) | 8 (0.9) | |
| Cystic | 93 (4.0) | 93 (6.6) | 0 (0.0) | |
| Spongiform | 9 (0.4) | 9 (0.6) | 0 (0.0) | |
| Echogenicity, n (%) | 2,309 | 1,418 | 891 | <0.01 |
| Hyperechoic/isoechoic | 486 (21.1) | 449 (31.7) | 37 (4.2) | |
| Hypoechoic | 1,524 (66.0) | 819 (57.8) | 705 (79.1) | |
| Markedly hypoechoic | 190 (8.2) | 41 (2.9) | 149 (16.7) | |
| Anechoic | 109 (4.7) | 109 (7.7) | 0 (0.0) | |
| Margin, n (%) | 2,506 | 1,458 | 1,048 | <0.01 |
| Microlobulated/irregular margin | 389 (15.5) | 67 (4.6) | 322 (30.7) | |
| Extrathyroidal extension | 117 (4.7) | 8 (0.6) | 109 (10.4) | |
| Ill-defined | 197 (7.9) | 40 (2.7) | 157 (15.0) | |
| Circumscribed | 1,803 (72.0) | 1,343 (92.1) | 460 (43.9) | |
| Calcification, n (%) | 2,244 | 1,472 | 1,038 | <0.01 |
| Microcalcifications | 777 (34.6) | 340 (23.1) | 570 (54.9) | |
| Comet-tail artifacts | 37 (1.7) | 37 (2.5) | 0 (0.0) | |
| Macrocalcifications | 230 (10.3) | 184 (12.5) | 179 (17.2) | |
| Peripheral calcifications | 52 (2.3) | 32 (2.2) | 20 (1.9) | |
| No echogenic foci | 1,148 (51.2) | 879 (59.7) | 269 (25.9) | |
| Shape, n (%) | 2,309 | 1,418 | 891 | <0.01 |
| Horizontal (wider-than-tall) | 1,561 (67.6) | 1,227 (86.5) | 334 (37.5) | |
| Vertical (taller-than-wide) | 748 (32.4) | 191 (13.5) | 557 (62.5) |
Data in parentheses are percentages unless otherwise indicated. §, analysis based on the number of patients. US, ultrasound.