A “blister” in the liver is a common term for what is medically known as a “liver cyst”, which is a benign condition. Usually there is no discomfort associated with liver cysts, and it may be that a doctor finds one or even a few blisters during an ultrasound examination at a medical checkup. A small number of cysts contain clear, transparent fluid as if it were a water balloon, but most cysts, especially smaller ones, do not contain any substance. Under ultrasound, one or more cysts can be seen, the larger ones up to 10 cm in diameter, while the smaller ones are only 1 cm in diameter. However, regardless of the size or number of cysts, they are usually not uncomfortable and do not affect the function of the liver. There is no definitive statement on how the cysts are created, and they may be related to the presence of many small bile ducts in the liver. There is another type of liver cyst that is genetically related, called “multiple-issue liver cysts”. In this case, new cysts grow in the liver and the liver becomes larger, even if the patient can feel the enlarged liver himself, sometimes with a little pain, and almost half of the patients also have kidney cysts. But again, there will be no liver dysfunction and no development of liver cancer. The cyst will neither affect liver function nor develop into liver cancer, so this cyst is usually left alone. However, if it grows too big and makes the patient feel uncomfortable, it can be treated. The doctor can insert a thin needle into the cyst under the guidance of ultrasound and use the thin needle to draw out the fluid inside the cyst and then inject pure alcohol so that the cyst will not grow again. If the cyst grows very large and the patient feels painful, open surgery can also be considered to remove the cyst along with the membrane of the cyst to solve the patient’s pain.