Thyroid fine-needle aspiration cytology in Taiwan: a nationwide survey and literature update

In Taiwan, thyroid fine-needle aspiration cytology is easily accessible and reliable for evaluating thyroid nodules. The sonographic pattern plays a major role and is the deciding factor for aspiration. We conducted a nationwide survey in 2017 and it revealed that 31% of laboratories had adopted The Bethesda System for Reporting Thyroid Cytopathology. There was a relatively high unsatisfactory rate (24.04%) and low rates of indeterminate diagnoses, including atypia of undetermined significance/follicular lesions of undetermined significance: 4.87%, and follicular neoplasm/suspicious for a follicular neoplasm: 0.35%. Moreover, the risks of malignancy in benign, atypia of undetermined significance, and suspicious for a follicular neoplasm were relatively high. These may reflect strict diagnostic criteria for indeterminate categories and better patient selection for surgery. Improvements in specimen sampling and continuing education programs are crucial. Newly-developed thyroid cytology technologies, such as immunocytochemistry, molecular testing, and computerized cytomorphometry, may further facilitate cytology diagnoses.