The presence of cysts in the liver is quite common. Up to 5% of the population has cysts in the liver that are discovered at the time of ultrasound, CAT scanning, or MRI. Very few patients have symptoms associated with these cysts and are found incidentally.
The cause of the cysts is not known and felt to be congenital in origin. The cysts in the liver are lined by biliary-type epithelium and may result from progressive dilation of biliary microhamartomas. The cysts in the liver are fluid-filled with fluid similar to the plasma found in the blood.
A subset of patients will have polycystic liver disease, which is hereditary in nature. The mutation for this disorder has been identified. In many cases, individuals that have polycystic liver disease also have polycystic kidney disease. In polycystic liver disease, numerous cysts develop in the liver. In this situation, the liver typically is enlarged and with the large number of cysts, there is stretching of the outer capsule of the liver, which may result in pain, bringing this to the attention of both the patient and their physician. Again in many cases, no specific therapy is warranted though in more extreme cases, it may be recommended that surgery is performed to drain these cysts. In other cases, liver transplantation may be required. Patients with polycystic kidney disease likewise may need to be considered for renal transplantation. It is not unusual for patients to receive both liver and kidney transplant at the same time.