Liver cysts 9mm are relatively small in size and most are benign lesions and usually not serious. However, if the volume increases to a certain extent, treatment is required. Most liver cysts are congenital cysts, but they can also be caused by acquired factors. When the diameter of the cyst is less than 5cm, the lesion is usually not serious and most of them do not cause clinical symptoms, so they do not need special treatment. However, in order to prevent liver cysts from further enlarging, it is recommended to go to the hospital regularly for liver ultrasound review. If the diameter of liver cysts is larger than 5cm, and accompanied by nausea, vomiting, fullness after eating and other uncomfortable symptoms, timely treatment is needed, usually using open drainage or partial hepatectomy for treatment. In summary, liver cyst 9mm is not serious, no special treatment is needed for the time being.