Clinicopathological Significance of Ultrasound Risk Features and the Taller-Than-Wide Sign for Tumor Advancement in Differentiated Thyroid Cancer: A Single-Center Analysis.

PURPOSE: Ultrasound (US) imaging plays a pivotal role in the preoperative assessment of thyroid cancer (TC). Suspicious US features, including hypoechogenicity, microcalcifications, high vascularity, irregular shape, irregular margins, and the taller-than-wide (TTW) sign, are widely used for preoperative risk stratification of thyroid nodules. This study aimed to investigate the associations between preoperative US features and histopathological indicators of tumor advancement in differentiated thyroid cancer (DTC). PATIENTS AND METHODS: We conducted a retrospective analysis of 665 patients with DTC who were treated between 2008 and 2024. Preoperative US features, including hypoechogenicity, microcalcifications, high vascularity, irregular shape, irregular margins, and the TTW sign, were correlated with extrathyroidal extension (ETE) and lymph node metastases (LNM). Associations were evaluated using Pearson's χ2 test, Fisher's exact test where appropriate, odds ratios (ORs), and Cramér's V. Statistical significance was defined as p < 0.05. RESULTS: All analyzed US features were significantly associated with histopathological indicators of tumor advancement (p < 0.05). Of all evaluated conventional US features, the strongest associations were observed between microcalcifications and ETE, and between high vascularity and LNM (Cramér's V = 0.32 and 0.38, respectively). The TTW sign was significantly associated with ETE (OR = 2.96, 95% CI: 1.73-5.07) and LNM (OR = 9.07, 95% CI: 5.07-16.24). CONCLUSION: Among US features, the TTW sign demonstrated particularly strong associations with histopathological indicators of tumor advancement, especially LNM. These findings support the potential value of comprehensive preoperative assessment of US features and warrant further prospective studies with multivariable modelling to better define the role of the TTW sign in preoperative risk stratification of DTC.