Thyroid adenoma is a common benign clinical thyroid tumor. It is a hemispherical mass that occurs in or near the middle of the neck, with smooth surface and clear edges, and can move up and down with swallowing movements. If the adenoma has insufficient blood circulation and degenerative lesions occur in the nodule, causing cyst formation, it is called thyroid cystadenoma or thyroid cyst. If the adenoma has symptoms of hyperfunction, it is called hyperfunctional adenoma, also known as toxic adenoma, but it is less likely to become malignant. Those with papillary changes in the adenoma are called papillary adenomas, which are more likely to become malignant.