Thyroglossal cysts are treated by surgery. Although the cyst may appear extremely well defined and superficial, lying just beneath the skin, the embryology described above means there can always be further cysts lying deep to the hyoid bone or extending up into the muscle of the tongue. Therefore, it is never sufficient simply to remove the cyst. The mid-portion of the hyoid bone must be removed at the same time, together with a core of muscle from the tongue. This combined operation is referred to as Sistrunk’s operation.