Liver cysts can be categorized as parasitic and non-parasitic. Non-parasitic liver cysts are further classified into congenital, traumatic, inflammatory, and neoplastic cysts. Congenital liver cysts are the most common in clinical practice and are divided into solitary and multiple types.
Solitary liver cysts are more commonly observed in individuals aged 20 to 50, with a male-to-female ratio of 1:4. These cysts are predominantly found in the right lobe of the liver. The size can range from a few millimeters in diameter for small cysts to more than 500 mL of fluid content for larger cysts, which can even occupy an entire liver lobe. Multiple liver cysts are more prevalent in females aged 40 to 60. These cysts vary in size and may distribute throughout the liver or be localized to a segment or lobe. The epithelial cells lining the inner wall of the cyst vary depending on its size, appearing columnar, cuboidal, flat, or absent altogether, while the outer layer consists of collagenous tissue. The cystic fluid is typically clear and transparent, with little to no bile content.
Congenital liver cysts grow slowly, and smaller cysts are often asymptomatic, usually discovered incidentally through imaging examinations or during surgery. Symptoms such as postprandial bloating, nausea, vomiting, and mild discomfort or dull pain in the right upper quadrant may occur if a cyst enlarges, compresses adjacent organs, or develops internal bleeding. Physical examination may reveal a right upper abdominal mass or hepatomegaly. The mass is connected to the liver, has a smooth surface with a cystic quality, shows no obvious tenderness, and moves with respiration.
Ultrasonography is the preferred diagnostic method for liver cysts. CT and MRI are useful for identifying the size, location, shape, and number of cysts. Large liver cysts may exhibit signs during an X-ray examination, such as diaphragmatic elevation or displacement of the stomach and intestines. For multiple liver cysts, other organs including the kidneys, lungs, and pancreas should also be checked for cysts (polycystic disease) or congenital anomalies. Differentiation from congenital intrahepatic bile duct dilation (Caroli disease) is necessary.
Asymptomatic liver cysts generally do not require special treatment. For large cysts accompanied by symptoms, treatment may be administered. Commonly used approaches include ultrasound-guided aspiration, laparoscopic fenestration or deroofing procedures, which involve the partial removal of the cyst wall and draining its contents to leave the cavity open. Open surgery for congenital liver cysts has become rare.
For complicated cases involving infection or cystic bleeding, drainage catheters may be left in place after aspiration or fenestration procedures and removed once the drainage clears. Cysts containing bile may require surgical intervention if aspiration alone is insufficient for control. In such cases, intraoperative suturing of the bile duct leak, drainage placement, and, if necessary, liver resection may be performed.
For multiple liver cysts, only large cysts that are likely to cause symptoms are typically addressed through either aspiration drainage or laparoscopic fenestration. For cases in which lesions are confined to a liver segment or lobe and symptoms are present, or when fenestration produces unsatisfactory results, liver segmentectomy or lobectomy may also be performed.