Abstract
Notes
CONFLICTS OF INTEREST
Young Joo Park is an editor-in-chief and Eun Kyung Lee is an associate editor of the journal. But they were not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.
ACKNOWLEDGMENTS
REFERENCES
Table 1.
Table 2.
Table 3.
Category | US patterns | Suggested malignancy risk, % | Nodule size threshold for biopsy, cmb |
---|---|---|---|
High suspicion (K-TIRADS 5) | Solid hypoechoic nodule with any of the three suspicious US featuresc | >60 | >1d |
Intermediate suspicion (K-TIRADS 4)e | 1) Solid hypoechoic nodules without any of the three suspicious US features or | 10–40 | >1–1.5g |
2) Partially cystic or iso-/hyperechoic nodule with any of the three suspicious US features | |||
3) Entirely calcified nodulesf | |||
Low suspicion (K-TIRADS 3) | Partially cystic or iso-/hyperechoic nodule without any of the three suspicious US features | 3–10 | >2 |
Benign (K-TIRADS 2)h | 1) Iso-/hyperechoic spongiform | 3 | Not indicatedi |
2) Partially cystic nodule with intracystic echogenic foci and comet-tail artifact | |||
3) Pure cyst | |||
No nodule (K-TIRADS 1) | - | - |
Modified from Ha et al. [1].
US, ultrasonography; K-TIRADS, Korean Thyroid Imaging Reporting and Data System.
a Biopsy should be performed regardless of the size of the most suspicious nodule in cases with poor prognostic factors, including suspected cervical lymph node metastases, obvious extrathyroidal extension to adjacent structures (trachea, larynx, pharynx, recurrent laryngeal nerve, or perithyroidal vessels), confirmed distant metastases, or suspected medullary thyroid cancer;
b Fine-needle aspiration (FNA) is the primary pathology test and core needle biopsy can be performed as an adjunctive pathology test to FNA; it should be performed by a trained operator [11,47];
c Suspicious US features of thyroid nodule: punctate echogenic foci, nonparallel orientation, and irregular margins;
d Biopsy is recommended for small (>0.5 and ≤1 cm) high suspicion (K-TIRADS 5) nodules with high-risk features, including attachment of nodules to the trachea or posteromedial capsule along the course of the recurrent laryngeal nerve considering the potentials of high-risk microcarcinomas requiring immediate surgery. Biopsy may be considered for small (>0.5 and ≤1 cm) K-TIRADS 5 nodules without high-risk features to decide the management plan in adults. In children, biopsy should be considered for small K-TIRADS 5 nodules (>0.5 and ≤1 cm) to decide the management plan considering the clinical context;
e Extensive parenchymal punctate echogenic foci (microcalcifications) without discrete nodules (suspicious for diffuse sclerosing variant of papillary thyroid carcinoma) and diffusely infiltrative lesions (suspicious for infiltrative malignancy, such as metastasis or lymphoma) are considered to be intermediate suspicion suspicion (K-TIRADS 4) nodules;
f Entirely calcified nodules with complete posterior acoustic shadowing, with no soft tissue component identified due to dense shadowing on US (isolated macrocalcification);
g Cutoff size for biopsy should be determined within the range of 1 and 1.5 cm, based on the US features, nodule location, clinical risk factors, and patient factors (age, comorbidities, and preferences);
Table 4.
Modified from Ali et al. [21], with permission from Mary Ann Liebert, Inc.
ROM, risk of malignancy; NIFTP, noninvasive follicular thyroid neoplasm with papillary-like nuclear features.
Table 5.
Modified from Jung [24].
ROM, risk of malignancy; CNB, core needle biopsy; NIFTP, noninvasive follicular thyroid neoplasm with papillary-like nuclear features.