Calcification of the thyroid gland means that the thyroid gland has been previously inflamed, damaged or bleeding, and eventually deposits of calcium are formed, often in different patterns found under ultrasonography, some with strong echogenicity, which is then considered as thyroid calcification. Calcified thyroid foci are usually used as a criterion to assess the benignity and malignancy of thyroid disease. If calcifications are found in the thyroid gland, coarse calcifications or eggshell-like calcifications are more likely to be considered benign, while if calcifications are found to be fine and sandy under ultrasound examination, they are more likely to be considered malignant. Therefore, the results of the ultrasound examination will be used to determine whether the calcification is benign or malignant, based on thyroid function, thyroid puncture biopsy and pathology results, before taking appropriate treatment measures.