Thyroid adenomas are the most common type of benign thyroid tumor and can be classified as follicular or papillary adenomas, the former being more common. Patients are mostly female and can occur at any age, but are often under 40 years old. Most patients do not experience any discomfort. Some may have localized swelling and pain due to intracapsular hemorrhage. Thyroid adenomas should be removed as early as possible because of the risk of malignancy of up to 10% and the possibility of hyperthyroidism (incidence about 20%). Clinical manifestations Usually no obvious conscious symptoms are produced, and often the anterior neck mass is found unintentionally. The tumor grows slowly and does not change much in the long term. On physical examination, it is mostly seen as a solitary mass, round or oval, with smooth surface, tough texture, clear border, no pressure pain, and can move with swallowing. If there is sudden bleeding in the tumor, the mass can be seen to increase rapidly with local pain and tenderness, and these symptoms can disappear within a week. Larger tumors can cause compression symptoms, which can be confirmed by X-ray of the neck. In a few cases, functionally autonomous thyroid adenoma with hyperthyroid symptoms may occur. If the tumor continues to increase in size, with restricted or fixed activity, hard texture and pressure symptoms such as hoarseness and difficulty in breathing, the possibility of tumor malignancy should be considered. Disease treatment The most effective treatment for thyroid adenoma is surgical removal. Since about 10% of adenomas can become malignant and surgery is more complicated after recurrence, simple removal of adenomas is not advocated. Surgical excision of the affected lobe is currently recommended, along with exploration of the lymph nodes surrounding the ipsilateral gland and, if necessary, rapid frozen pathology to prevent missing the cancer. For high-functioning adenomas, appropriate preoperative preparation is required to prevent the occurrence of postoperative thyroid crisis.