Liver cysts are one of the most common benign diseases of the liver, and the vast majority of patients are diagnosed by ultrasound during a physical examination, usually without any symptoms. Liver cysts are usually spherical in shape, with a fibrous cyst wall and a clear, colorless or yellowish cyst fluid inside. Most liver cysts are very small, about 1-2 cm in diameter, about the size of a grape, but some can grow very large, up to 10-20 cm or more in diameter, like a balloon full of water. Liver cysts can be single or multiple. Liver cysts can grow anywhere in the liver, in the left lobe, in the right lobe, or in both the left and right lobes. Liver cysts can be superficial or deep in the liver parenchyma, some even close to the large intrahepatic vessels. In general, liver cysts do not rupture, bleed, become infected, or become malignant. However, intracapsular hemorrhage may occur in a few patients, resulting in a bloody cyst fluid or with blood clots. Sometimes infection can occur. Most liver cysts remain “quiescent” or grow very slowly for a long time and are asymptomatic, so most patients do not need treatment, but the prerequisite is a clear diagnosis of liver cysts. In most cases, the diagnosis can be confirmed by ultrasound, but in cases where ultrasound does not make a clear diagnosis and metastatic tumors, liver encapsulation, polycystic liver disease, etc. are suspected, a CT or MRI is needed to confirm the diagnosis. Even blood tests, such as tumor markers, are performed to rule out neoplastic disease. Although most liver cysts are asymptomatic, some patients with “small cysts” still feel discomfort or pain in the abdomen, which may be due to the superficial location of the cysts that easily rub against the diaphragm or peritoneum, or may be combined with other abdominal diseases, such as gastric or duodenal ulcers, which may require gastroscopy to exclude these diseases. Gastroscopy is needed to exclude these diseases. In general, pain caused by liver cysts is not serious. However, large liver cysts can squeeze the surrounding organs and cause discomfort or fullness in the abdomen, even affecting digestion and breathing. What kind of liver cysts need to be treated For most patients, they are small liver cysts, the maximum diameter of which does not exceed 3 cm, which will neither affect liver function nor develop into liver cancer, and will have no impact on patients’ life and living. However, the following cases should be considered for treatment 1. Huge liver cysts or cysts with clinical symptoms A few liver cysts grow faster or the cysts are larger when they are found. When the diameter exceeds 10 cm, it can be called a giant liver cyst. Huge liver cysts tend to cause compression symptoms, such as fullness after eating or even when not eating, which affects normal work and study, and treatment needs to be considered. Of course, there are few patients who have cysts that do not reach 10 cm in diameter, but due to the special growth site, such as the caudate lobe of the liver, the left outer lobe of the dirty surface, etc., they cause discomfort to the surrounding organs such as stomach, duodenum, bile ducts compression, and cause discomfort, then treatment is needed. 2, cyst secondary infection Liver cysts generally rarely become secondary to infection, but a few liver cysts can become secondary to infection, and these patients can show inflammatory manifestations such as pain in the liver area, fever, elevated white blood cells in routine blood tests, and ultrasound examination can show thickened cyst wall, poor cyst fluid transmission, etc. These patients should not continue to be observed, but should be treated promptly. 3.Cyst secondary bleeding A few of liver cysts can have spontaneous rupture of cyst wall blood vessels leading to intracapsular bleeding. Some patients do not have obvious symptoms, but some patients have severe pain in the liver area, cool like acute abdomen, such as conservative treatment without effect for surgery. 4. Clinically rare cystic tumors There are some clinically rare tumors that can also manifest as cystic lesions in the liver, such as hepatobiliary cystic adenocarcinoma, hepatobiliary cystic adenoma, hepatic mesothelioma, hepatic lymphoma, hepatic lymphadenoma, etc. Because they are very rare, it is very difficult to make a correct diagnosis, and these patients need to be treated surgically. Treatment of hepatic cysts There are three main methods for the treatment of hepatic cysts: One is hepatic puncture and aspiration. In this method, the cystic fluid is aspirated with a fine needle under ultrasound guidance. Some people also advocate injecting drugs such as anhydrous alcohol after the cyst fluid is extracted to destroy the cells that secrete cyst fluid. However, since this method does not completely destroy the cells secreting cystic fluid, the recurrence rate of cysts is high, and repeated punctures tend to cause intracapsular bleeding and cystic fluid infection. There is also a less common case in which the cystic fluid is connected to the bile duct, and after the injection of drugs that destroy the cystic wall, it also causes damage to the bile duct, which can cause serious damage to the patient if such complications occur. Therefore, this method is only suitable for patients who have a temporary solution to the more severe symptoms of compression, but cannot tolerate or do not want to undergo surgical treatment. The second is hepatic cystotomy. The key of the operation is to remove most of the cyst wall after aspiration of the cyst fluid, which is called “windowing” because the treatment of the cyst wall is like opening a skylight. After the window is opened, the cells of the cyst wall that secrete cystic fluid will be completely destroyed by drugs and other methods, so the chance of recurrence after surgery is small. Due to the rapid development of laparoscopic surgery, liver cyst surgery can also be performed laparoscopically, and the surgery is less invasive than open surgery, and the patient recovers quickly. However, for cysts deep in the liver parenchyma, traditional open surgery should still be chosen as safer. For liver cysts with combined bleeding or infection, if conservative treatments such as clinical anti-infection and puncture and fluid extraction are ineffective, or if malignant liver cystic tumors or liver encapsulation cannot be excluded, the whole cyst can be completely and thoroughly removed. What is polycystic liver disease? In what cases is treatment necessary? How is it treated? Polycystic liver disease is an autosomal dominant disease caused by genetic mutation, so it is also called hereditary multiple cysts in the liver, and most of the clinical patients have polycystic kidney disease at the same time. This disease is a benign disease of liver, with insidious onset and slow development, generally no clinical symptoms in the early stage, as the cysts increase, it can gradually cause epigastric distension and discomfort, weakness, poor performance, epigastric mass and other symptoms, serious can lead to inferior vena cava compression, hepatic venous outflow tract obstruction, portal hypertension and biliary tract obstruction, liver failure, etc., and then cause ascites, gastrointestinal bleeding and jaundice, and the cysts also The patients who need surgical intervention are also the ones with symptoms, and the main surgical options are: percutaneous aspiration of cystic fluid, cystotomy, partial hepatectomy with cystotomy, and liver transplantation.