1.What is a liver cyst? A liver cyst is commonly referred to as a “blister” in the liver. The vast majority of liver cysts are congenital, that is, due to certain abnormalities in congenital development that lead to the formation of liver cysts. Acquired factors are rare, such as parasitic cysts in the liver in pastoral areas where people have contracted encapsulated cysticercosis. Trauma, inflammation, and even tumors can also cause liver cysts. Cysts can be single, just one, as small as 0.2 cm, or as many as ten or dozens, or even one as large as tens of centimeters. Patients with multiple hepatic cysts are sometimes combined with cysts of other internal organs, such as concomitant renal cysts, pulmonary cysts and occasionally pancreatic cysts and splenic cysts. Hepatic cysts are a relatively common benign disease of the liver and can be classified as parasitic, non-parasitic and congenital hereditary. Most of the hepatic cysts are caused by developmental disorders of small intrahepatic bile ducts, and the occurrence of solitary hepatic cysts is due to ectopic bile ducts. The clinical manifestations vary with the location, size and number of cysts, as well as the presence or absence of compression of adjacent organs and the presence or absence of complications. 2. Clinical manifestations of liver cysts. Liver cysts are usually asymptomatic. 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 abdominal pain and fever due to cysts secondary to bacterial infection. Patients with cysts compressing the stomach dare not eat normally or have full meals, and heart failure can occur when squeezing the heart, and some patients have cysts in the left lobe of the liver that squeeze the heart. Oxygen must be administered every day and they did not get out of bed for two years because of heart failure. After treatment patients are able to walk on the floor and no longer need oxygen. Liver cysts can present with pain in the liver area, abdominal distension, and sometimes sudden enlargement of the cyst or secondary infection can suddenly increase abdominal pain, or fever. Sometimes a mass can be palpated in the upper abdomen, and some patients develop abdominal pain, vomiting, and jaundice. Hepatic cysts are cystic enlargement of localized tissues of the liver and have little effect on human health. When small in size, there are no obvious symptoms and they are often detected during abdominal ultrasonography or abdominal surgery and do not require treatment. When the cyst is too large, symptoms such as indigestion, nausea, vomiting and discomfort or pain in the right upper abdomen may occur. A small number of liver cysts can have the following conditions, such as cyst rupture, intracapsular bleeding, infection or rapid growth with malignant tendency in a short period of time, so regular examination and observation are needed for all liver cysts and treatment if necessary. Usually cysts smaller than 5cm do not have any symptoms, so no treatment is needed, you just need regular ultrasound examinations to observe its changes. While cysts larger than 5cm can cause complications due to compression of surrounding organs or important structures, such as liver cysts compressing bile ducts causing bile duct dilatation; kidney cysts compressing renal artery or renal pelvis causing secondary hypertension or hydronephrosis; larger cysts on the surface of liver and kidney even have the risk of rupture. At this time, treatment is needed as needed. 3.Diagnostic methods of liver cysts Liver cysts mainly rely on imaging examination for diagnosis. Ultrasonography is the most important among the imaging diagnostics. In terms of characterization of liver cysts, ultrasonography is generally considered more accurate than CT. However, CT is clearly better than ultrasound in guiding surgery when it comes to a comprehensive understanding of the size, number and location of cysts and related organs in and around the liver, especially in patients with massive liver cysts that require treatment. In general, magnetic resonance imaging (MRI) is not required for patients with liver cysts. Laboratory tests are of little value for the diagnosis of liver cysts. Usually, liver cysts do not cause abnormalities in liver function. However, sometimes some blood tests are still necessary for differential diagnosis. 4.Treatment of liver cyst (1) Chinese medicine and western medicine can not make the cyst disappear or shrink, so the liver cyst is not treated with medicine. (2) Surgical treatment. Surgical methods include transabdominal or translaparoscopic cyst opening and decompression, because cysts are mostly encapsulated in liver parenchyma and it is difficult to peel off the whole cyst. Often the surgery causes more trauma and affects the aesthetics due to the surgical scar. Although laparoscopic cyst opening and decompression solves the problem of surgical trauma and postoperative aesthetics, patients need to be treated under general anesthesia for laparoscopic treatment, and the cost for patients of the above two procedures is higher. (3) Sclerotherapy of cyst under ultrasound guidance. At present, ultrasound intervention is widely used in clinical practice. Ultrasound-guided aspiration treatment for liver and kidney cysts is to select the shortest and safest route under ultrasound monitoring, use a fine needle to accurately pierce the cyst through the skin, aspirate the cyst fluid, and then inject anhydrous alcohol according to the nature of the intracapsular fluid to make the cyst sclerosis and no longer grow. It is a minimally invasive treatment that feels almost equivalent to a single subcutaneous injection, with an average outpatient treatment time of about 30 minutes to go home the same day of treatment, and usually no medication changes or other treatments after surgery. The treatment effect is observed by ultrasound 3 to 6 months after surgery. Ultrasound-guided interventional treatment of liver and kidney cysts has completely replaced the traditional surgical treatment. It is less invasive, less painful and less expensive, and can achieve the same effect as surgical dissection under minimally invasive conditions, and is even safer and more effective than surgery for some special parts of lesions that are not suitable for surgery. The application of this treatment method is becoming more and more widespread and popular, and the ultimate beneficiaries are the majority of patients.