Cysts are usually benign, malignant ones don’t appear as cysts, malignant ones are solid nodules that are full of tumor cells, cancer cells. Cysts have a cystic wall, and inside the cystic wall is a packet of water, so they are called cysts under the description of ultrasound or CT. There are congenital and acquired cysts, congenital cysts usually occur in the liver and kidneys, and they are often frequent. Generally speaking, they are relatively small in size, so they can not be used for surgery and further treatment, but only need to pay attention to follow up when checking, to see if there is any increase in the size of the cysts, and whether there are any symptoms of compression. If the cyst is large, for example, its diameter is more than 10 centimeters, or even larger, and it has already pressed the normal liver or kidney tissues, then it is necessary to do some open drainage surgery. Acquired cysts are more commonly seen as cystic changes in breast nodules or nodular goiter, but these are also benign diseases. If they are large and have compression symptoms, surgery is also needed to treat them.