Fine needle aspiration cytology guided by ultrasound in the diagnosis of subcentimetre thyroid nodules

Background This study aimed to investigate the value of fine needle aspiration biopsy (FNAB) under ultrasound guidance in diagnosis of thyroid nodules. In a retrospective analysis of FNAB in 1050 cases of patients with 1100 nodules, patients were divided according to the maximum diameter of their nodules into two groups: >1.0 and ≤1.0 cm. The ultrasound-guided FNAB cytology results were compared between two groups. Results Ultrasound findings showed that among 1100 thyroid nodules, 547 were highly suspicious, 358 were moderately, 175 were low, and 19 were very low. Cytology results showed papillary carcinomas in 453, possible papillary cancer in 126 cases, follicular tumors in 26, suspicious follicular tumors in 6, atypical cells in 7, nodular goiter in 289, colloid in 13, chronic lymphocytic thyroiditis in 175, and undiagnosed specimen in 5. Ultrasound diagnosis of thyroid nodules had an overall sensitivity of 86.0 %, and a specificity of 81.9 %. In nodules larger than 1.0 cm, the sensitivity was 92.8 %, and the specificity 92.3 %. In nodules ≤1.0 cm, the sensitivity was 82.4 %, and the specificity was 81.7 %. Conclusions Patients with highly suspicious thyroid nodules on ultrasonography, regardless of nodule sizes, should receive ultrasound-guided FNAB to confirm their natures and direct clinical managements.