Etiology Thyroid cysts are one of the common lesions of benign occupations of the thyroid gland. Its etiology is not known. It may be related to iodine metabolism, sex hormones, regional, dietary habits and family. Most scholars believe that thyroid cysts are associated with iodine deficiency, especially in China. Clinical presentation The disease occurs mostly in women aged 20-40 years. The cysts are mostly solitary, but can also be multiple. The masses are round or round-like, varying in size from as small as peanut rice to as large as a duck egg. The surface is smooth, the border is clear, the texture is soft, it moves up and down with swallowing, and there is no tenderness or pressure. The cysts increase slowly and generally do not show any clinical discomfort. Occasionally, due to bleeding within the cyst, the swelling may increase rapidly within a short period of time, and local pain and pressure symptoms may appear, which may be accompanied by hoarseness and dyspnea. The disease is generally not malignant. Ultrasound can be used to make a clear diagnosis of cystic lesions in the thyroid gland, which are mostly solitary with clear borders. The swelling can sometimes reach the subclavian bone and the posterior sternum. 2.Nuclear thyroid scan such as 131I scan shows a “cold” nodule in the thyroid gland. 3.CT and MRI examination If the swelling is large or accompanied by compression symptoms, it is necessary to perform CT or MRI examination of the thyroid gland to observe the compression of surrounding tissues and organs and to generally guide the treatment. 4.Thyroid function In general, TSH, T3 and T4 are normal. Diagnosis According to the thyroid gland appears without any swelling, smooth surface, soft texture, moving up and down with swallowing, no pressure pain. The diagnosis is confirmed by a nuclear scan of a “cool” nodule in the thyroid gland and an ultrasound examination of a cystic mass with a smooth surface. Differential diagnosis Thyroid cysts and thyroid adenomas are both benign, solitary, asymptomatic occupations in the thyroid gland. The adenoma is tougher and the cyst is softer, and can be differentiated by ultrasound. In patients with thyroid cysts, the thyroid gland on the healthy side is usually not large and only the thyroid lobe on the affected side is enlarged; in nodular goiter, both thyroid lobes are enlarged, the texture is tougher, and the single nodule can evolve into multiple nodules over time. Nuclear scan and ultrasound can help to differentiate them. Treatment Although thyroid cysts do not have any clinical symptoms, they should be treated for any diagnosed thyroid cysts because of their continuous enlargement and the risk of bleeding within the cyst. For small cysts superficial and less than 3 cm in diameter, non-surgical treatment is available. Local puncture aspiration followed by anhydrous ethanol irrigation with 1-2 ml of anhydrous ethanol reserved is sufficient. This method is less invasive, less painful, more effective and more acceptable to patients, but there is a risk of secondary bleeding. For deep-surface thyroid cysts or those with a diameter greater than 3 cm, surgical removal is safer and more reliable. Prevention Thyroid cysts are benign lesions of the thyroid gland. If there is a recurrence after perfusion with anhydrous ethanol by puncture, re-perforation and perfusion can be performed. The prognosis of surgery is good, and occasional recurrence can be treated by surgery again.