The treatment for 2.1mm cysts in the thyroid gland, if asymptomatic, is usually regular review, if the cysts continue to grow, there is a possibility of malignant changes, may also need to carry out cyst aspiration treatment and surgical treatment. 1. General treatment: most of the thyroid cysts are benign, and some of them can be gradually absorbed within a few months, and a thyroid cyst of 2.1mm is not considered large, so for asymptomatic and small benign cysts, regular checkups are usually enough, and no special treatment is needed. 2. Cyst aspiration: for larger benign cysts, the contents of the cyst can be aspirated under ultrasound guidance to reduce the size of the cyst. 3. Surgery: If the cysts become malignant or increase rapidly in size within a short period of time, surgery is recommended. In the case of a 2.1mm cyst in the thyroid gland, it is recommended to go to the hospital and ask the doctor to formulate an individualized treatment plan according to the specific situation.