Generally, precancerous lesions have the possibility of transforming into cancer, suggesting early changes and very good treatment effect, but thyroid cancer does not have the term precancerous lesions at present, unlike gastrointestinal tumors. If this is the case, it may be considered a precancerous lesion. If the ultrasound classification is TI-RADS category 4 or higher, and the thyroid puncture reveals atypical hyperplasia with anomalous cells and follicular cells, surgical treatment should be considered. If ultrasound suggests category 3 and below, puncture without clear tumor cells can be observed. In contrast, thyroid cancer is definitively diagnosed, which means that the malignant cells seen by puncture are thyroid cancer, while if the puncture suggests atypical hyperplasia it can also be called as having precancerous lesions.