Recent topics on thyroid cytopathology: reporting systems and ancillary studies

As fine-needle aspiration techniques and diagnostic methodologies for thyroid nodules have continued to evolve and reporting systems have been updated accordingly, we need to be up to date with the latest information to achieve accurate diagnoses. However, the diagnostic approaches and therapeutic strategies for thyroid nodules vary across laboratories and institutions. Several differences exist between Western and Eastern practices regarding thyroid fine-needle aspiration. This review describes the reporting systems for thyroid cytopathology and ancillary studies. Updated reporting systems enhance the accuracy, consistency, and clarity of cytology reporting, leading to improved patient outcomes and management strategies. Although a single global reporting system is optimal, reporting systems tailored to each country is acceptable. In such cases, compatibility must be ensured to facilitate data sharing. Ancillary methods include liquid-based cytology, immunocytochemistry, biochemical measurements, flow cytometry, molecular testing, and artificial intelligence, all of which improve diagnostic accuracy. These methods continue to evolve, and cytopathologists should actively adopt the latest methods and information to achieve more accurate diagnoses. We believe this review will be useful to practitioners of routine thyroid cytology.