Utilization of Molecular Testing in Thyroid Cytology

This is the authors' abstract. We don't add key points for this paper.

Thyroid nodules are a common finding in the general population. The differential diagnoses of these lesions encompass numerous entities, both nonneoplastic and neoplastic. Fine-needle aspiration cytology is the most important diagnostic tool for evaluating thyroid lesions. It has found worldwide application because of its simplicity, safety, and cost-effectiveness, and its essential role is mainly focused on the discrimination between benign and malignant neoplasms. Increasing knowledge of molecular mechanisms of thyroid cancer, combined with an inability to definitively characterize a proportion of cases cytologically, has encouraged research into and clinical utilization of molecular techniques on fine-needle aspiration cytology samples. In particular, BRAF, RET/PTC, or RAS alterations are found in more than 70% of papillary thyroid carcinomas, and some of them are associated with more aggressive tumor behavior. Furthermore, there is evidence of correlation of BRAF mutations with extrathyroidal extension, advanced tumor stage, and nodal or, less frequently, distant metastases. We believe that molecular testing can contribute to patient management, as an ancillary tool, in selected thyroid cases. However, molecular studies should not be ordered indiscriminately as a reflex test, and their results must not replace cytologic interpretation and clinical judgment.