In our clinical practice, we often encounter patients who have thyroid nodules that are not very large on ultrasound. Their thyroid nodules are not very large by ultrasound, but they have calcification. How should we handle these patients properly? In general, calcification is less common in benign thyroid diseases, and is usually due to inflammation, hematoma absorption, calcification of the nodule wall or calcification of the fibrous septum. Calcification in the center of malignant thyroid tumors is due to rapid growth of cancer cells and proliferation of tumor blood vessels and fibrous tissue. Calcium salt deposition occurs, which leads to calcification. Second, how is calcification of the thyroid gland classified? At present, thyroid calcification is classified into 2 categories 1. Coarse calcification: the diameter of calcified nodules in ultrasound examination is >2mm, and the ultrasound shows calcified foci with strong light clusters, lamellae, arcs or other irregular morphology. Irregular morphology was observed in pathological tissue sections. 2, microcalcifications: the diameter of calcified nodules ≤ 2 mm, ultrasound performance is mostly pinpoint-like, granular, dotted, sand-like. The diameter of 60 to 100 um in pathological tissue section is round or sand grain-like. the calcification points ≤2 mm in ultrasonography reflect the microcalcifications observed in pathological tissue section, but the detection rate of microcalcifications in ultrasonography is relatively low. Third, understand the relationship between calcification and thyroid tumors Benign thyroid lesions show less calcification, most of which are coarse calcification, while the incidence of microcalcifications is low. Malignant thyroid tumors have a higher incidence than coarse calcifications. This is the opposite of benign lesions. It is generally believed that the coarser the calcification particles, the better the differentiation of the cancer tissue. The characteristics of calcification shadows may be related to the classification of cancer as follows: 1. Sand-like calcification is almost common to malignant thyroid tumors and is often a characteristic manifestation of papillary carcinoma. 2. Among the coarse calcification images, about 10%-20% are carcinoma, among which follicular thyroid cancer accounts for a large proportion. Medullary carcinoma with coarse particles and sand-like calcifications are often mixed. 4. Generally, the calcification images of benign thyroid tumors are mostly coarse calcifications with clear edges. In contrast, the shadows of malignant tumors are faint and blurred. It is generally accepted that microcalcifications are the most specific index for diagnosing thyroid cancer by ultrasound, with 83%-90.3% in the literature and 93%-95% for papillary carcinoma. Therefore, if a thyroid nodule with calcification is found during physical examination, it is important to seek prompt medical attention. In particular, patients with microcalcifications should not be taken lightly and should be alerted to the possibility of malignant thyroid tumors. In general, these patients should be actively treated with surgery.