Liver cysts usually do not cause swelling of the thighs, but as the size of liver cysts increases, liver function is damaged, resulting in a decrease in albumin production, and swelling of the thighs occurs. In another case, huge liver cysts compress the inferior vena cava behind the liver, causing obstruction of venous return to the lower extremities, and swelling of the lower extremities may also occur. Liver cyst volume is very small, there is no clinical manifestation, often found by chance during physical examination, the patient’s liver function is not damaged, there will be no synthesis of albumin obstruction, resulting in swelling of the thighs, but with the increase in the volume of liver cysts, if the serious impact on the liver function, it will cause a decrease in albumin, resulting in swelling of the thighs. Therefore, patients with liver cysts do not need to be treated when the size is very small, and they should have a regular review of abdominal ultrasound or abdominal CT to understand the changes in the size of the liver cysts; when the size of the liver cysts increases, they need to be removed surgically, or else it will lead to abnormalities in liver function. If the patient has any discomfort, go to the hospital in time, do not be careless, so as not to delay the treatment.