[Fine-needle Aspiration of Thyroid Nodules: Is it Worth Repeating?]

Introduction: The fine-needle aspiration has a significant role in assessing the malignancy risk of thyroid nodules. There is uncertainty regarding the value of repeat fine-needle aspiration in benign nodules. This study aims to evaluate the concordance of results in consecutive fine-needle aspiration and to study the relevance of repetition in benign results.

Material and Methods: Retrospective study of the 4800 thyroid nodules fine-needle aspiration held in Instituto de Patologia e Imunologia Molecular da Universidade do Porto between January 1, 2014 and May 2, 2016. Of the initial sample, we selected the repeated fine-needle aspiration on the same nodule.

Results: The first fine-needle aspiration result of the 309 nodules underwent revaluation was non-diagnostic in 103 (33.3%), benign in 120 (38.8%) and atypia/follicular lesion of undetermined significance in 86 (27.8%). The agreement between the first and second fine-needle aspiration was significantly higher in cases with an initial benign result (benign: 85.8%, non-diagnostic: 27.2% and atypia/follicular lesion of undetermined significance: 17.4%, p < 0.005). The fine-needle aspiration repeating motifs in initially benign nodules (n = 78) were repetition suggestion in 58, nodule growth in 17 and suspicious ultrasonographic features in 3.

Discussion: The fine-needle aspiration repetition in nodules with initial non-diagnostic and atypia/follicular lesion of undetermined significance result changed the initial diagnosis in a significant proportion of patients, modifying their therapeutic approach. The high concordance of results in initially benign nodules makes fine-needle aspiration repetition not cost-effective in most cases.

Conclusion: The fine-needle aspiration should be repeated when the initial cytology result is non-diagnostic or atypia/follicular lesion of undetermined significance.