Current Perspectives on Thyroid Nodule Evaluation: Integrating Cytomorphology, Ultrasound Risk Stratification, and Molecular Testing.

Fine-needle aspiration biopsy (FNAB) remains the cornerstone of preoperative evaluation of thyroid nodules and represents one of the most enduring and successful applications of cytopathology in clinical medicine. Over the past decade, however, the role of thyroid FNAB has evolved considerably. This transformation reflects advances in ultrasound-based risk stratification systems; refinements in cytologic reporting, culminating in the third edition of the Bethesda System for Reporting Thyroid Cytopathology, ongoing international harmonization initiatives including the forthcoming World Health Organization (WHO) Reporting System for Head and Neck Cytopathology (WHO RSHNC); the integration of molecular diagnostic testing into routine workflows; and major revisions in thyroid tumor classification introduced in the fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. Collectively, these developments have shifted thyroid FNAB from a predominantly morphologic screening modality to a central component of a multidimensional, precision-based diagnostic pathway. In contemporary practice, thyroid FNAB operates within an integrated clinical framework that combines imaging-based risk assessment, cytomorphologic interpretation, molecular testing, and risk-adapted management strategies. This review summarizes the current status of thyroid FNAB with emphasis on FNAB indications, specimen adequacy, cytomorphologic interpretation within the Bethesda framework, management of indeterminate thyroid nodules, and the expanding role of molecular classifiers. Emerging diagnostic and management approaches, including artificial intelligence, radiogenomics, active surveillance and ablation therapies, are also discussed. Attention is given to the practical implications of these advances for surgical pathologists and cytopathologists engaged in multidisciplinary thyroid nodule management.