Introduction: Surgical pathologies of the thyroid are frequent; essential tools for its assessment constitute ultrasound, Fine Needle Aspiration (FNA), and Pathological Anatomy (PA) of the resected sample.

Objective: To determine the correlation between sonographic, cytological and pathological findings of thyroid nodules in years.

Materials and methods: Observational, descriptive and retrospective study of thyroidectomized patients between 2010 and 2014 at Clinical’s Hospital-Uruguay.

Results: Sixty-seven patients, 59 women and 8 men, with a mean age of 45 ± 16 years. According to ultrasound findings, the majority corresponded to EU-TIRADS 3 (43%), followed by EU-TIRADS 4 (27%). According to Bethesda classification, the most frequent was indeterminate (48%), followed by benign (32%) and malignant (19%). 54% had benign PA and 46% malignant, papillary carcinoma was the most frequent (61%).

Discussion: A significant association between EU-TIRADS 4-5 and the Bethesda classification was demonstrated. The finding of a probably benign (EU-TIRADS 3) or suspicious (EU-TIRADS 4) nodule, whose risk described in the literature of 2-4% and 6-17%, can hide a malignant tumor in up to 1/4 or 6 /10 cases respectively. Sensitivity of ultrasound was 74% and specificity 66%. The ultrasound elements significantly related to malignancy were the solid variant, hypoechoic and the presence of microcalcifications. Bethesda classification categories clearly associated with malignancy were IV, V, and VI.

Conclusions: An adequate correlation was demonstrated to differentiate benignity from malignancy when comparing ultrasound findings of thyroid nodules with FNA and PA.