Medullary carcinoma of the thyroid gland is relatively rare and it is difficult to differentiate from other types of thyroid cancer under ultrasound, and most of them are diagnosed only after surgery with pathology. Under ultrasound, thyroid cancer usually appears as a solid nodule, usually hypoechoic or very hypoechoic, with blurred margins, some of which are lobulated or superficially lobulated. Some nodules can have irregular halos around the periphery, some can show pinpoint calcifications or other types of calcifications, and most of them can show attenuation posteriorly. The blood supply within the tumor of a thyroid nodule is richer and will obviously be more internal than peripheral with arterial high resistance blood flow.