Table 2.
Characters of thyroid nodules and differences between children and adults thyroid nodules.
| A. Sonographic patterns of thyroid nodules and estimated risk of malignancy [24]. | ||
| Sonographic Pattern | US Features | Estimated Risk of Malignancy |
| High suspicion | Solid hypoechoic nodule or solid hypoechoic component of a partially cystic nodule with one or more of the following features: irregular margins (infiltrative, microlobulated), microcalcifications, taller-than-wide shape, rim calcifications with small extrusive soft tissue component, evidence of extrathyroidal extension |
>70–90% |
| Intermediate suspicion | Hypoechoic solid nodule with smooth margins without microcalcifications, extrathyroidal extension, or taller-than-wide shape |
10–20% |
| Low suspicion | Isoechoic or hyperechoic solid nodule, or partially cystic nodule with eccentric solid areas, without microcalcification, irregular margin or extrathyroidal extension, or taller-than-wide shape. | 5–10% |
| Very low suspicion | Spongiform or partially cystic nodules without any of the sonographic features described in low, intermediate, or high suspicion patterns | <3% |
| Benign | Purely cystic nodules (no solid component) | <1% |
| B. Differences between pediatric and adult thyroid nodules | ||
| Difference | Pediatric | Adults |
| Epidemiology [4,5] | Less common. Nodule prevalence: 0.2–5% | More common Nodule prevalence: 19–35% |
| Higher likelihood of malignancy (25%) | Lower likelihood of malignancy (10%) | |
| Histology/Stage [3] | Higher incidence of regional lymph node involvement, extrathyroidal extension, and pulmonary metastasis | Lower incidence of regional lymph node involvement, extrathyroidal extension, and pulmonary metastasis |
| Prognosis [11] | More favorable progression-free survival in children Mortality rate ~0.1% in patients aged < 20 |
Less favorable progression-free survival in adults Maximum mortality rate up to 27.4% in patients aged 75–84 |
| Molecular [3] | Higher prevalence of gene rearrangements and a lowerfrequency of point mutations in the proto-oncogenes implicatedin PTC | Lower prevalence of gene rearrangements and a higherfrequency of point mutations in the proto-oncogenes implicatedin PTC |
| BRAF mutations are the less common abnormality in children PTC | BRAF mutations are the most common abnormality in adult PTC (36–83% of cases) | |
| RET/PTC rearrangements are more common in PTC from children | RET/PTC rearrangements are less common in adult PTC | |
| Sonographic characteristics [8,25,26,27,28,29] | The malignancy rate is increased with increasing nodule size | The nodule’s size is not associated with increased malignancy risk |
| Color Doppler analysisis not a useful differentiating characteristic in the identification of thyroid cancer | Color Doppler analysis has incremental value in the identification of malignancies | |
| Patients with an abnormal background sonographic appearance documented a higher risk of malignancy | A higher risk of malignancy is not documented for patients with an abnormal background sonographic appearance | |
| Diffuse sclerosing variant PTC, with abundant microcalcifications is more common in children | Diffuse sclerosing variant PTC with abundant microcalcifications is less common in adults | |