A. Typical thyroid cancer usually appears as follows: irregular hypoechoic mass with rough edges and fine gravel-like calcifications. It may also appear as: 1) a regular hypoechoic mass with loose internal structure and fine calcifications; 2) an isoechoic or hyperechoic mass with irregular morphology and lobulated margins; 3) a mixed mass with solid hypoechoicity, often with fine calcifications and less liquid components located at the edge of the mass; 4) a diffuse lesion involving part or all of the thyroid gland, which may be accompanied by diffuse calcifications. The following features should be noted: 1. Microscopic thyroid carcinoma is mostly located under the thyroid envelope, but it may also appear as an intact envelope. 2. Rich blood supply is not necessarily a characteristic of thyroid cancer. 3. A thyroid mass with intact envelope (more than 3 cm) should be noted as follicular carcinoma when it is accompanied by abundant blood supply. 4. A significant proportion of coarse calcifications are malignant. 5.Eggshell-like calcification or arcuate calcification is often benign. 6.Unclear border may be a manifestation of nodular goiter. When thyroid cancer metastasizes to lymph nodes, the lymph node ultrasound shows: the ratio of long to short axis is reduced, the internal echogenicity is enhanced and thickened, and the lymphatic portal structure disappears. More characteristic changes: small calcified spots, partial or total cystic changes and fusion changes in the lymph nodes. Lymph node enlargement in the central region due to Hashimoto’s thyroid inflammation is often difficult to distinguish from metastasis. 4. The following diagnoses should be considered in thyroid ultrasound in cancer hospitals and surgery is recommended: 1. MT cannot be excluded or MT to be excluded (about 50%); 2. MT is possible (about 90%); 3. MT (basically malignant). The probability of malignancy increases in order. Puncture may be considered for the following diagnoses on thyroid ultrasound in cancer hospitals: Substantial thyroid mass, close follow-up is recommended.