In general, about 25% of thyroid nodules show calcified shadows, while 50% to 62.5% of thyroid cancers have calcifications. It is generally believed that the coarser the calcification particles are, the better the differentiation of the cancer tissue. The characteristics of calcification shadows may have the following relationships with cancer classification: 1. Granular calcification, which is almost common to malignant thyroid tumors, is often a characteristic manifestation of papillary carcinoma. 2. About 10%-20% of the coarse calcified images are carcinoma, among which follicular adenocarcinoma accounts for a large proportion. Medullary carcinoma is often mixed with coarse particles and sand-like calcifications. 4. Generally, calcified images of benign thyroid tumors are more dense with clear edges, while malignant tumors are faint and blurred in shadows. The above is an introduction to the clinical significance of calcification of thyroid nodules. Through the above description, we can see that the characteristics of calcified shadows of thyroid nodules may be related to cancer classification. Patients must go to a professional hospital when doing the diagnosis of calcification of thyroid nodules to avoid any missed diagnosis.