About 5% of liver cysts are cystic tumors, including cystadenomas and cystadenocarcinomas. Cystadenomas are often misdiagnosed as liver cysts and treated with repeated aspiration and incomplete resection, resulting in recurrence or residual cysts. Cystadenomas can malign to cystic adenocarcinoma and are seen in the elderly. Cystadenoma of the liver should be treated surgically even if it is asymptomatic. Complete resection of the tumor is preferred, as partial resection is highly prone to recurrence and possible malignancy. The prognosis of cystadenoma is better than other solid tumors of the liver and cholangiocarcinoma, and radical surgery is the only effective treatment, including partial resection of the surrounding normal liver tissue or regular lobectomy. Therefore, most cases are eligible for radical surgery, and if the tumor can be confined to the resected liver, no further treatment is needed after surgery. The 5-year survival rate for surgical resection of cystic adenocarcinoma of the hepatobiliary duct has been reported to be 87%. MRI presentation] It is difficult to differentiate cystadenoma from cystic adenocarcinoma on imaging, but cystic adenocarcinoma tends to be more coarsely segregated and soft tissue forming lesions with significant low signal in T1WI and significant high signal in T2WI, and enhancement is seen in the delayed phase of enhancement scan because of internal segregation. Soft tissue can be continuously strengthened A. T2WI fat suppression: a large mass is seen in the right liver, consisting of low signal solid component and high signal cystic part; B. T1WI isotopic image: varying degrees of signal enhancement of the cystic part within the tumor; C. Solid part is strengthened; D. Delayed phase: strengthening is still seen. Differential diagnosis】 Differentiation from polycystic liver.