Table 1. Frequency and Risk of Malignant Thyroid Nodules According to Solidity, Echogenicity, and Combination of Solidity and Echogenicity.
| Pattern | No. of Nodules (n = 902) | No. of Malignant Nodules (n = 266) | Malignancy Risk (%) |
|---|---|---|---|
| Solidity | |||
| Solid | 715 (79.3) | 253 (95.1) | 35.4 |
| Predominantly solid | 134 (14.9) | 11 (4.1) | 8.2 |
| Predominantly cystic | 45 (5.0) | 2 (0.8) | 4.4 |
| Cystic | 8 (0.8) | 0 (0.0) | 0.0 |
| Partially cystic (predominantly solid/cystic) | 179 (19.8) | 13 (4.9) | 7.3 |
| Echogenicity | |||
| Markedly hypoechoic | 76 (8.4) | 53 (19.9) | 69.7 |
| Mildly hypoechoic | 398 (44.1) | 197 (74.1) | 49.5 |
| Isoechoic | 423 (46.9) | 15 (5.7) | 3.5 |
| Hyperechoic | 5 (0.6) | 1 (0.4) | 20.0 |
| Hypoechoic (marked or mild) | 474 (52.5) | 250 (94.0) | 52.7 |
| Isohyperechoic | 428 (47.5) | 16 (6.0) | 3.7 |
| Combination of solidity and echogenicity | |||
| Solid hypoechoic | 436 (48.3) | 242 (91.0) | 55.5 |
| Solid isohyperechoic | 279 (30.9) | 11 (4.1) | 3.9 |
| Partially cystic hypoechoic | 38 (4.2) | 8 (3.0) | 21.1 |
| Partially cystic isohyperechoic | 141 (15.6) | 5 (1.9) | 3.5 |
| Partially cystic or isohyperechoic | 466 (51.7) | 24 (9.0) | 5.2 |
Numbers in parentheses are percentages.