Thyroid adenomas are the most common benign tumors of the thyroid gland and can be classified as follicular or papillary cystic adenomas. The former is more common and has an intact envelope, while papillary cystic adenoma is rare and not easily distinguished from papillary adenocarcinoma. The disease is most commonly seen in women under 40 years of age. Clinical manifestations: round or oval nodules in the neck, mostly solitary. It is slightly hard with smooth surface, no pressure pain, and moves up and down with swallowing. Most patients have no symptoms. When intracapsular hemorrhage occurs, the tumor may rapidly increase in size and become locally distended and painful. Treatment: The incidence of hyperthyroidism caused by thyroid adenoma is about 20% and the incidence of malignancy is about 10%, so most or part of the affected thyroid tissue including the adenoma (small adenoma) should be removed early. The excised tissue should be examined pathologically.