The Importance of the Taller-than-Wide Feature and the Dimensions of Focal Thyroid Lesions in Assessing the Risk of Malignancy.

Background/Objectives: A taller-than-wide shape is considered a suspicious ultrasound feature in the assessment of thyroid nodules. Although previous studies indicate an association with malignancy, its predictive value may vary depending on the population, methodology and measurement criteria. This study aimed to evaluate the diagnostic significance of the TTW feature and selected nodule dimensions in predicting malignancy risk. Methods: A retrospective observational study was conducted including 367 patients with thyroid nodules referred for fine-needle aspiration biopsy. Nodule height, width and the height-to-width ratio were assessed and compared with cytological outcomes according to the Bethesda classification. Spearman rank correlation and logistic regression analyses were performed, and the predictive value of the TTW ratio was evaluated using receiver operating characteristic analysis. Results: A statistically significant but weak positive correlation was observed between Bethesda category and both nodule height and the product of height and width (p < 0.05; r < 0.3). No significant association was found between the TTW ratio and lesions requiring further clinical evaluation and potential surgical management (OR = 1.03; p = 0.931). The area under the ROC curve for the TTW ratio was 0.497, indicating limited discriminatory performance between benign and potentially malignant lesions. Conclusions: In this cohort, the TTW feature showed limited predictive value in assessing malignancy risk. It should not be used as a standalone criterion for biopsy or surgery, but interpreted as part of a comprehensive ultrasound-based risk assessment together with cytological findings. Further studies in larger populations and with standardized ultrasound measurement protocols are warranted.