Unmasking risk in low-suspicion thyroid nodules: clinical and sonographic predictors of malignancy in TIRADS 3, a retrospective single-center study.

BACKGROUND

Thyroid nodules categorized as TIRADS 3 are typically considered low risk for malignancy (estimated < 5%) under the 2017 ACR TI-RADS guidelines. However, the real-world application of these criteria may vary, with many TIRADS 3 nodules undergoing fine-needle aspiration (FNA) despite recommendations for surveillance. This study aimed to identify clinical and ultrasonographic predictors of malignancy in TIRADS 3 nodules to enhance risk stratification.

METHODS

This retrospective, single-center study included 200 patients aged 18-65 years with ultrasound-confirmed TIRADS 3 thyroid nodules who underwent FNA between January 2021 and December 2022. Although ACR guidelines recommend biopsy for nodules ≥ 2.5 cm, FNA was also performed in smaller nodules presenting with high-risk features such as capsule bulging or central-peripheral vascularity. Data were collected from anonymized hospital records. Multivariate logistic regression was used to identify independent predictors of malignancy.

RESULTS

The malignancy rate was 20%, exceeding the expected threshold for TIRADS 3 nodules. Capsule expansion (OR 18.50, p < 0.001), central-peripheral vascularity (OR 4.99, p = 0.004), and a family history of thyroid cancer (OR 13.08, p = 0.001) were identified as significant predictors. All malignancy diagnoses were based on cytological findings (Bethesda V/VI), with no histopathologic confirmation available.

CONCLUSION

Certain TIRADS 3 nodules may possess a higher malignancy risk than traditionally assumed. Incorporating additional ultrasound features and clinical context may improve diagnostic accuracy. Future prospective studies with histopathological confirmation are warranted to validate these predictors.