Polycystic liver disease (PLD) is a rare, genetic condition marked by the development of multiple cysts throughout the liver. These cysts are closed, fluid-filled sacs that can vary in size from small to several inches in diameter. While the liver can become quite enlarged due to the growth of these cysts, its function often remains normal. The severity of the condition and the presence of symptoms vary greatly, and many people remain unaware they have it.
Causes and Associated Conditions
Polycystic liver disease is a genetic disorder inherited from a parent. The condition arises from mutations in specific genes that affect the normal development of cells within the liver. For isolated PLD, where the disease occurs without affecting other organs, mutations are often found in genes such as PRKCSH and SEC63.
A significant portion of PLD cases occurs with Autosomal Dominant Polycystic Kidney Disease (ADPKD). In these instances, the genetic mutations are in the PKD1 or PKD2 genes. Individuals with ADPKD commonly develop liver cysts, but it is possible to have PLD without any kidney involvement.
The growth of these liver cysts is influenced by age and sex. Symptoms and disease severity are more common in women, as the female hormone estrogen may contribute to cyst growth. This is supported by growth accelerating during a woman’s childbearing years and slowing after menopause.
Symptoms and Complications
Many people with polycystic liver disease experience no symptoms, and the cysts are often discovered by chance during medical imaging. When symptoms do arise, they are not from liver dysfunction but from the physical enlargement of the liver, known as hepatomegaly. This enlarged organ can press on adjacent structures in the abdomen.
The most common symptoms include:
- A persistent feeling of fullness or bloating in the abdomen
- Pain or general discomfort
- Early satiety, which is feeling full after eating only a small amount
- Shortness of breath if the enlarged liver pushes against the diaphragm
- A visible and progressive swelling of the abdomen
- Back pain and gastroesophageal reflux
While severe complications from PLD are uncommon, they can occur. A cyst may rupture or bleed internally, causing sudden and sharp abdominal pain. An infection of a cyst is another complication, which can lead to fever and localized pain. In rare instances, the cysts can compress bile ducts or major blood vessels, and progression to complete liver failure is exceedingly rare.
Diagnosis Process
The diagnosis of polycystic liver disease is primarily achieved through medical imaging. An abdominal ultrasound is frequently the initial diagnostic tool because it is non-invasive and widely available. It can effectively detect the fluid-filled sacs characteristic of PLD.
For a more detailed assessment, a physician may order a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan. These advanced imaging techniques provide a comprehensive view of the liver, offering precise information about the extent of the cystic disease. A formal diagnosis is made when imaging reveals the presence of 10 or more cysts in the liver.
While imaging is the primary method of diagnosis, blood tests are also a standard part of the evaluation. These tests assess the liver’s overall health by measuring levels of liver enzymes. However, they cannot diagnose PLD, as liver function is often normal even with extensive cysts.
Management and Treatment Approaches
Treatment is unnecessary for asymptomatic individuals with polycystic liver disease, so a “watchful waiting” strategy is common. Active treatment is reserved for those whose quality of life is affected by symptoms like persistent pain or significant abdominal distension.
When symptoms become bothersome, the initial approach involves medications for discomfort. For more significant symptoms from large cysts, minimally invasive procedures like cyst aspiration may be used. This involves draining a large cyst with a needle for temporary relief, often followed by sclerotherapy to prevent it from refilling.
In more severe cases, surgical options are available. One procedure is cyst fenestration, or “deroofing,” where a surgeon removes the outer walls of large, accessible cysts to drain them and reduce liver volume. For a very small percentage of patients with extreme hepatomegaly, a partial liver resection may be performed.
Liver transplantation is the only curative option but is considered a last resort. This major surgery is reserved for rare instances where the disease has led to a profoundly diminished quality of life and other treatments have failed.