Thyroid nodule cysts are often formed as a result of rupture of the nodule, which increases in size in a short period of time. A so-called cyst is a cystic wall on the outside and a fluid environment encased on the inside. Localized hypointense shadows can be detected by ultrasound, and dark areas of fluid can be seen within the mass. Cystic nodules usually appear after the fluid inside the cyst absorbs itself. Larger cysts may develop compression symptoms such as pain, difficulty in swallowing, hoarseness, difficulty in breathing, etc. Cysts may be left untreated if there is no change in size. If it is larger than 1 cm, it proves to be an indication for surgery and can be surgically removed, or puncture can be done to extract the cystic fluid, etc. In addition, if the cyst is accompanied by more pain, inflammatory manifestations and high blood count, it can be anti-inflammatory first, and then surgery can be performed when the blood count returns to normal.