Liver cysts are fluid-filled sacs that can develop within the liver. They are a common finding, often discovered incidentally during medical imaging for other health concerns. Most are benign and typically do not cause symptoms or health problems.
What is a Liver Cyst?
The majority of liver cysts are “simple cysts.” These benign, fluid-filled sacs are often present from birth. They are believed to form due to a malformation in the bile ducts during embryonic development, where small fluid-filled pockets fail to connect properly with the main biliary system.
Simple cysts are generally not associated with underlying liver disease or damage. While simple cysts are the most common type, other less frequent forms exist, such as those caused by parasitic infections (like hydatid cysts) or those linked to genetic conditions like polycystic liver disease (PLD), which involves multiple cysts throughout the liver.
Size and Significance
Simple liver cysts vary in size, often ranging from a few millimeters to several centimeters in diameter. Many remain small, less than 3 centimeters, and do not cause any symptoms. These smaller cysts are frequently detected by chance during imaging tests for unrelated issues.
The size of a liver cyst is an important factor in its clinical assessment. Small cysts are almost always asymptomatic and usually do not require any intervention or ongoing monitoring. Even larger cysts, which can be several centimeters across, are typically benign. While many cysts remain stable in size over long periods, some can grow slowly over time.
When Size Becomes a Concern
A liver cyst’s size becomes a concern when it grows large enough to cause symptoms. Cysts exceeding 5 centimeters in diameter are more likely to produce noticeable effects due to their physical mass. Common symptoms include a dull pain or discomfort in the upper right abdomen, a feeling of fullness or bloating, and early satiety, meaning a person feels full quickly after eating only a small amount of food. These symptoms arise from the cyst pressing on nearby organs or structures.
In rare instances, a very large cyst might obstruct bile ducts, leading to jaundice, or put pressure on major blood vessels. Medical professionals monitor larger cysts, especially those causing symptoms, often through follow-up imaging like ultrasound or CT scans. If symptoms are persistent and interfere with daily life, interventions may be considered. These can include percutaneous drainage, where fluid is removed from the cyst with a needle, or surgical removal, such as laparoscopic deroofing. While such interventions are uncommon, they are typically effective in relieving symptoms.