”Doctor, I feel that my stomach is bloated, and it is getting more and more bloated, and I seem to feel a ball-like object in my upper abdomen, which has recently increased in size and seems to have elasticity, does this mass matter?” We can sometimes meet such patients in the outpatient clinic, who are generally in good condition, and after lying down, we can find a bulging stomach, and sometimes we can feel a cystic mass with elasticity and fluctuation. The majority of liver cysts are congenital, and liver cysts, commonly referred to as “blisters” in the liver, are caused by some congenital developmental abnormality that leads to the formation of liver and kidney cysts. Cysts can be solitary, just one, as small as 0.2 cm, and can often be clinically encountered in liver cysts, with isolated cysts being the most common. Isolated liver cysts are usually asymptomatic, do not require medication if liver function is normal, and generally should not be surgically removed. There can also be as many as a dozen or dozens, or even one that is as large as several tens of centimeters. In the Shanghai Zhongshan Hospital data, there was a 77-year-old male patient with a liver cyst whose mass was so large that it extended from the abdominal cavity to the pelvis. Unless the cyst is huge, it can be surgically removed if it presents with symptoms of compression. If the cyst is large compression symptoms such as abdominal pain, nausea and diarrhea may occur. The site of cysts is mostly in the right liver. Generally, patients with good general condition and normal liver function can have open-heart surgery to reduce pressure, relieve symptoms and promote regeneration of hepatocytes, which is considered to be cured as long as they do not produce symptoms. Some patients often have upper abdominal mass as the first symptom, and at the end stage, ascites, portal hypertension and other symptoms of liver insufficiency appear. When the cyst grows to a certain extent, it may compress the gastrointestinal tract and cause symptoms such as epigastric discomfort and fullness. There are also cases of abdominal pain and fever due to cysts secondary to bacterial infections. If the cyst is complicated by bacterial infection, it can be treated with antibiotics first, and if the inflammation is still not controlled, a so-called “open window” surgery can be performed. This is to cut away a piece of the cyst wall and drain the fluid from it. This surgery has little impact on health. The detection rate of liver and kidney cysts by ultrasound can reach 98%, so many people will find liver cysts during medical examinations. Even more, this liver is full of dense, large and small cysts, called polycystic liver. Polycystic liver cysts are also called polycystic liver, and more than half of the patients have polycystic kidneys in combination. Polycystic liver often invades the whole liver, and there are a few patients with polycystic liver whose lesions are limited to one lobe or half of the liver. When cysts are numerous and large, in addition to upper abdominal discomfort, the increased pressure can cause atrophy of the liver parenchyma, thus requiring surgical treatment. In polycystic liver, the cysts may cover the liver, and some patients often have upper abdominal masses as the first symptom, with ascites, portal hypertension and other signs of liver insufficiency at the end stage. In severe cases, the liver is densely packed with large and small cysts that cannot be removed, with little liver parenchyma and impaired liver function, and liver transplantation is then required to completely eradicate the disease. Acquired factors are rare, such as in pastoral areas, such as people infected with cysticercosis, in the liver will produce parasitic cysts, the author in aid work in Xinjiang encountered a number of cases of liver cysticercosis, due to the rare Shanghai area, thus not repeated. In addition, trauma, inflammation, and even tumors can also cause liver and kidney cysts. A cyst is a tumor that grows on top of the liver, even though there are not many symptoms, it is also very uneasy, will it turn into liver cancer? Congenital hepatic and renal cysts are not cancerous. The common complications of liver and kidney cysts are rupture and bleeding, bacterial infection, fistula and penetration, while cancer is rare. Treatment of liver cysts does not require medication and the principle of surgery is also symptomatic and affects liver function. In the past, open surgery was the conventional treatment. With the progress of minimally invasive techniques, for the patient just seen in the outpatient clinic, as his liver function was normal and the cyst was within the resectable range, we chose the most suitable treatment for him, laparoscopic resection and decortication of the liver cyst with intraoperative attention to the bile ducts and blood vessels. The patient’s postoperative abdominal distension disappeared, liver function recovered well and he was discharged in three days.