Importance of clinical, ultrasound and cytological characteristics in predicting malignancy in thyroid nodules with indeterminate cytology.

[INTRODUCTION/OBJECTIVES] To identify demographic, ultrasonographic and cytological features that could improve the management of thyroid nodules with indeterminate cytology.

[METHODS] From 592 patients with indeterminate cytology (2008-2022), 77 were included after excluding those without histopathological confirmation or with non-PTC malignancies. Demographic, clinical, ultrasound, and cytological features were analyzed as predictors of malignancy.

[RESULTS] Malignancy rates were 32.3% for Bethesda III, 63.2% for Bethesda IV, and 77.8% for Bethesda V. Multiple logistic regression identified hypoechoic (OR 7.8,  = 0.0021) and isoechoic (OR 6.7,  = 0.0093) nodules, along with nuclear clefts (OR 3.8,  = 0.0381), as independent predictors of malignancy.

[CONCLUSION] Younger patient age, the presence of hypo- or isoechogenicity on ultrasound, and nuclear atypia (nuclear clefts) on cytology are associated with a higher risk of malignancy in thyroid nodules with indeterminate cytology. Integrating these readily accessible markers offers a practical and cost-effective strategy for risk stratification in indeterminate nodules.