Table 1. Frequency and risk of malignancy for cytological indeterminate thyroid nodules based on ultrasonographic features.
| Ultrasonographic feature | Malignant (n = 12) | Benign (n = 29) | Risk of malignancy (%) | P Value |
|---|---|---|---|---|
| Composition | 0.62 | |||
| Cystic or almost completely cystic | 0 (0.0) | 0 (0.0) | 0 | |
| Spongiform | 0 (0.0) | 0 (0.0) | 0 | |
| Mixed cystic and solid | 1 (8.3) | 6 (20.7) | 14.3 | |
| Solid or almost completely solid | 11 (91.7) | 23 (79.3) | 32.4 | |
| Echogenicity | 0.09 | |||
| Anechoic | 0 (0.0) | 0 (0.0) | 0 | |
| Hyperechoic | 0 (0.0) | 0 (0.0) | 0 | |
| Isoechoic | 1 (8.3) | 12 (41.4) | 7.7 | |
| Hypoechoic | 11 (91.7) | 17 (58.6) | 39.3 | |
| Very hypoechoic | 0 (0.0) | 0 (0.0) | 0 | |
| Shape | 0.41 | |||
| Wider-than-tall | 10 (83.3) | 28 (96.6) | 26.3 | |
| Taller-than-wide | 2 (16.7) | 1 (3.4) | 66.7 | |
| Margin | 0.04 | |||
| Smooth | 1 (8.3) | 12 (41.4) | 7.7 | |
| Ill defined | 5 (41.7) | 10(34.5) | 33.3 | |
| Lobulated or irregular | 4 (33.3) | 7 (24.1) | 36.4 | |
| Extra-thyroidal extension | 2 (16.7) | 0 (0.0) | 100 | |
| Echogenic foci1 | 0.75 | |||
| None or larger comet tail artifacts | 5 (38.5) | 16 (50.0) | 23.8 | |
| Macro calcification | 5 (38.5) | 9 (29.4) | 35.7 | |
| Peripheral calcification | 0 (0.0) | 0 (0.0) | 0 | |
| Punctate echogenic foci | 3 (23.0) | 7 (20.6) | 30 |
1 Two subcategories coexisted in 4 nodules. Number in parentheses is percentages.