Multiple liver cysts are benign lesions that are usually combined with other organ cysts, such as polycystic kidneys. The cysts are usually congenital, and most of them can exist in single or multiple states. The boundaries of the cysts are clear, and the cystic fluid stored within them is not easy to detect, but may be found incidentally during a physical examination, which may be distributed in all lobes of the liver or confined to the tubules of the liver and gallbladder. The composition of the cystic fluid changes with the type and size of the cyst and the presence or absence of complications. In polycystic liver, the cystic fluid is clarified; if there is intracystic hemorrhage, the cystic fluid is brown or red; if there is complication of infection, the cystic fluid may be purulent. MRI: The borders are clear and smooth, T1WI low signal, T2WI high signal, gadolinium contrast enhancement early and late, and delayed enhancement is always non-enhancing. When combined with hemorrhage can be seen in the liquid-liquid plane and T1WI compression fat diffuse high signal, infected liver cysts can be manifested as liver abscess characteristics. A:T2 fat suppression: multiple hepatic and renal cysts, high signal, and some renal cysts with hemorrhage appear low signal; B: T1 isophase: very low signal relative to the liver, and hemorrhagic renal cysts can be seen as high signal; C. T1 enhancement imaging: no enhancement; D. Delayed phase: no enhancement. [Pathologic manifestations] Multiple cystic structures lined with columnar epithelium [Differential diagnosis] Other diseases causing intrahepatic multiple cystic liver injury, such as cholangiocarcinoma, Caroli’s disease.