A hyoid cyst is a cyst formed when the thyroglossal duct does not completely degenerate and disappear during human embryonic development and remains after birth, mainly manifesting as a protrusion or something cystic below the thyroid hyoid bone, which does not exist in normal people. If the hyoid cyst becomes larger with age after birth, the patient needs to be treated in the hospital and judged by the doctor; the differential diagnosis is made by swallowing movements to see if the patient’s neck protrusion moves with the thyroid gland. If the protrusion is active with the thyroid gland, it is a thyroglossal cyst. This is a benign disease, and if the patient is more concerned or psychologically worried, surgical removal is recommended without any risk.