Simple liver cysts are fluid-filled cavities in the liver. Usually, they cause no symptoms and need no treatment. However, they may become large enough to cause pain or discomfort in the upper right part of the abdomen.

Most liver cysts can be seen on ultrasound or CT scans. When needed, treatment may include drainage or removal of the cyst.

The cause of simple liver cysts isn't known. They may be the result of a malformation present at birth. Rarely, liver cysts may mean a serious, underlying condition such as:

• Polycystic liver disease, a disorder that runs in families.
• Echinococcus infection, a parasitic infection.
• Liver cancer.