Polycystic liver disease is a rare genetic condition that causes multiple fluid-filled sacs to grow throughout the liver, often without any symptoms. While most people live normal lives without knowing they have it, some may experience discomfort as the cysts grow larger and more numerous.
What Is Polycystic Liver Disease?
Polycystic liver disease, often abbreviated as PLD, is a rare condition where numerous cysts—fluid-filled sacs—develop throughout the liver. Imagine a healthy liver as having a smooth, uniform appearance, much like a solid organ. In someone with PLD, the liver can look like a cluster of grapes, with cysts of varying sizes scattered across its surface and within its tissue. These cysts are not cancerous, but their presence can change the liver’s size and shape over time.[1]
The condition is genetic, meaning it is passed down through families or, less commonly, occurs randomly due to spontaneous genetic changes. What makes PLD particularly interesting is that it often exists in two different forms. The most common form occurs alongside autosomal dominant polycystic kidney disease (ADPKD), where cysts develop in both the kidneys and liver. This form accounts for about 70% of all PLD cases. The second form is called isolated PLD, which affects only the liver and makes up about 30% of cases. People with isolated PLD generally have a better long-term outlook because they don’t face the kidney complications that come with ADPKD.[1][2]
Despite the presence of multiple cysts, most people with polycystic liver disease never experience symptoms. In fact, many don’t even know they have the condition unless it’s discovered accidentally during a scan performed for another reason. The liver continues to function normally in the vast majority of cases, even when cysts are present. This is because the liver has remarkable capacity to maintain its essential functions despite structural changes.[3]
How Common Is Polycystic Liver Disease?
Polycystic liver disease is considered rare, affecting approximately 1 in every 100,000 people worldwide. However, these numbers may be underestimated because so many people with PLD never develop symptoms and therefore never receive a diagnosis. The actual prevalence could be higher than reported, with some estimates suggesting that between 5 and 10 in every 100 people may have liver cysts, though not all would meet the criteria for PLD.[9]
The condition affects women far more severely than men. Women are not only more likely to develop symptoms but also tend to have more cysts that grow larger. Studies show that females are about six times more likely than males to experience severe disease. This difference is thought to be related to the hormone estrogen, which appears to stimulate cyst growth. Because of this hormonal influence, symptoms often become more pronounced during or after pregnancy, or in women taking hormone-based medications like birth control pills or hormone replacement therapy.[1][4]
Most people don’t discover they have PLD until they reach their 50s. This is when cysts typically become large enough to be detected on imaging scans or when symptoms finally develop. In fact, up to 80% of people with PLD only receive their diagnosis incidentally after having a scan for an unrelated medical issue.[8]
What Causes Polycystic Liver Disease?
Polycystic liver disease is fundamentally a genetic condition. Most people inherit it from a parent who carries the genetic mutation, but it can also occur spontaneously without any family history. When PLD is inherited, it follows what doctors call an autosomal dominant pattern. This means that if one parent has the genetic mutation, each child has a 50% chance of inheriting it. However, even within the same family, people can have very different experiences with the disease. Some family members may have severe symptoms while others have none at all.[1][2]
Several genes have been identified as playing a role in PLD. For isolated polycystic liver disease—the form that affects only the liver—genetic changes in the PRKCSH and SEC63 genes are the most common culprits. These genes are responsible for producing proteins called hepatocystin and sec-63, which play important roles in fluid transportation and the growth of cells lining the bile ducts. When these genes don’t work properly, the normal development of bile ducts is disrupted, leading to cyst formation.[1][2]
Other genes linked to PLD include ALG8, GANAB, LRP5, and PKHD. However, these identified genes account for less than 50% of all PLD cases. This suggests that many other genes, yet to be discovered, are also involved in causing the condition. Ongoing research continues to explore the genetic landscape of PLD to better understand why cysts form and grow.[1]
When PLD occurs as part of ADPKD, different genes are responsible. The PKD1 and PKD2 genes, which produce proteins called polycystin 1 and polycystin 2, are the primary culprits. These proteins normally regulate fluid secretion and cell growth. When mutations affect these genes, the result is dysregulation of these processes, ultimately leading to cyst formation in both the kidneys and liver.[2]
Understanding the Development of Liver Cysts
The formation of liver cysts in PLD begins during fetal development. The process involves problems with the formation of the biliary tree—the network of tubes that carry bile from the liver to the intestine. During normal development, these bile duct structures form in a carefully orchestrated process. In people with PLD, genetic defects disrupt this process, causing some bile duct structures to become disconnected from the main biliary system. These disconnected structures eventually fill with fluid and become cysts.[6]
These early abnormalities often remain dormant for many years. While the structural changes occur during fetal development, cysts typically don’t begin growing significantly until adulthood. This explains why most people don’t experience symptoms until middle age or later. The cysts can vary enormously in size—from as small as a pinhead to as large as 4 inches across. Similarly, some people may have just a handful of cysts while others have hundreds scattered throughout their liver.[4]
Who Is at Risk for Polycystic Liver Disease?
The strongest risk factor for developing PLD is having a family history of the condition. Because it is typically inherited in an autosomal dominant pattern, children of affected parents have a 50% chance of inheriting the genetic mutation. If you have an immediate family member—a parent or sibling—diagnosed with PLD, other family members should consider being tested for the condition, even if they have no symptoms.[4]
Being female significantly increases the risk of developing severe symptoms from PLD. While men can certainly have the condition, women are much more likely to have larger and more numerous cysts. This gender difference is so pronounced that women are about six times more likely than men to experience severe disease requiring treatment. The hormone estrogen appears to be the key factor driving this difference, as it stimulates cyst growth. Women who have had multiple pregnancies, who take hormonal contraceptives, or who use hormone replacement therapy may experience more aggressive cyst growth.[1][4]
People with polycystic kidney disease, particularly ADPKD, are at very high risk for developing liver cysts. In fact, most people with ADPKD will have liver cysts by their mid-thirties. The frequency of liver cysts increases with age and with advancing kidney disease in this population.[4][5]
Symptoms of Polycystic Liver Disease
Most people with polycystic liver disease experience no symptoms at all. You could have numerous cysts throughout your liver and feel perfectly fine. This is because the liver has remarkable resilience and continues to perform its essential functions even when cysts are present. Many people only discover they have PLD when a scan performed for another reason—such as investigating abdominal pain or during a routine health check—reveals the cysts.[1][3]
When symptoms do occur, they typically develop because the liver has become so enlarged with cysts that it begins to press on surrounding organs and structures. The most common symptoms are abdominal pain and swelling. The pain can range from a dull ache to sharp discomfort, and it’s often felt in the upper right part of the abdomen where the liver is located. A swollen abdomen may occur either because the enlarged liver itself takes up more space, or due to fluid buildup in the abdominal cavity, a condition called ascites.[1]
Many people with enlarged livers full of cysts report feeling full after eating only a small amount of food. This condition, called early satiety, happens because the large liver crowds the stomach, leaving less room for food. This can make it difficult to maintain proper nutrition and may lead to unintended weight loss or changes in eating patterns.[1]
In severe cases, when cysts become very large, they can press upward on the diaphragm—the muscle that separates your chest from your abdomen and plays a crucial role in breathing. This pressure can make it difficult to take deep breaths, leading to shortness of breath, especially when lying down. Some people also experience back pain if the enlarged liver pushes on back muscles, or heartburn when pressure on the stomach causes acid to flow back into the food pipe.[1]
While less common, some people experience complications from their cysts. These can include severe pain from a ruptured cyst, fever and pain from an infected cyst, or yellowing of the skin and eyes (jaundice) if cysts block bile ducts. These complications require immediate medical attention.[4][9]
How Is Polycystic Liver Disease Diagnosed?
Diagnosing polycystic liver disease typically begins with imaging tests that can visualize the inside of the liver. The most common first test is an ultrasound scan. This non-invasive test uses sound waves to create pictures of the liver and can easily detect the presence of cysts. If cysts are found, doctors may order additional imaging tests such as a CT scan (computed tomography) or MRI scan (magnetic resonance imaging) to get more detailed information about the number, size, and location of cysts.[1][4]
Finding a few cysts on a liver scan doesn’t automatically mean you have PLD. Simple liver cysts are actually quite common, especially as people age, and they’re usually harmless. The diagnosis of PLD requires meeting specific criteria. Generally, doctors diagnose PLD if you have more than 20 cysts in your liver and no family history of the condition. If you do have a family member with PLD, the threshold is lower—having more than 4 cysts if you’re over 40 years old, or more than 1 cyst if you’re under 40.[4][8]
An important part of the diagnostic process is determining whether the PLD is isolated (affecting only the liver) or associated with polycystic kidney disease. When someone is diagnosed with liver cysts, doctors should order imaging of the kidneys—typically an ultrasound or MRI—to check for kidney cysts. If kidney cysts are present in sufficient numbers, the diagnosis may be ADPKD rather than isolated PLD. This distinction is crucial because it affects long-term health outlook and the need for additional monitoring and treatment.[3]
Your doctor will also take a detailed medical history, asking about family members who may have had PLD, ADPKD, or unexplained liver or kidney problems. They’ll perform a physical examination to feel for an enlarged liver and may order blood tests to check liver function. The good news is that blood tests measuring liver function usually remain normal in PLD, even when cysts are numerous, because the remaining healthy liver tissue continues to work effectively.[4]
In some cases, genetic testing may be recommended, especially when the diagnosis is unclear or when family members want to know if they carry the genetic mutation. Genetic counseling can help people understand their risk and make informed decisions about testing and family planning.[6]
How the Disease Changes Normal Liver Function
Understanding what happens inside the liver in PLD requires looking at the microscopic level. The fundamental problem in PLD is the abnormal development and behavior of cells lining the bile ducts. These epithelial cells, which normally form orderly tubes to transport bile, begin to behave abnormally due to genetic defects. Instead of forming proper bile duct structures, they create disconnected pockets that fill with fluid, forming cysts.[2]
The genetic mutations in PLD affect proteins that normally regulate fluid transport and cell growth. When these proteins don’t work correctly, fluid accumulates inside the disconnected bile duct structures, and the cells lining these structures continue to secrete more fluid. Over time, this process causes the cysts to grow larger and larger. Additionally, the normal signals that tell cells when to stop growing are disrupted, allowing cyst-lining cells to proliferate more than they should.[2][6]
What’s remarkable is that despite these changes, the liver usually maintains its ability to perform its essential functions. The liver has enormous reserve capacity and can continue working even when a significant portion of its tissue is replaced by cysts. Blood tests measuring liver function typically remain normal in most people with PLD. However, as cysts become very large and numerous, they can compress the healthy liver tissue and blood vessels running through the liver, potentially affecting blood flow and function in rare cases.[3]
Research has shown that the development of each individual cyst requires not just the inherited genetic mutation but also additional genetic changes (called somatic mutations) that occur within specific liver cells throughout a person’s lifetime. This “two-hit” mechanism helps explain why cyst development varies so much between individuals, even within the same family who share the same inherited mutation.[6]
Prevention and Early Detection
Because polycystic liver disease is a genetic condition, there is no way to prevent it entirely. If you inherit the genetic mutation, you will have PLD. However, there are steps you can take to potentially slow cyst growth and reduce the risk of symptoms developing or worsening.[5]
For women with PLD or at risk of developing it, avoiding or limiting exposure to estrogen may help slow cyst growth. This means considering alternatives to estrogen-containing birth control pills or hormone replacement therapy. If you’re taking these medications and have PLD, discuss with your doctor whether alternative options might be more appropriate for you. Many women with PLD notice that their cysts grow more rapidly during pregnancy or while taking hormonal medications.[9][16]
Family screening is an important preventive strategy. If you’ve been diagnosed with PLD or ADPKD, your immediate family members—children, siblings, and parents—should be informed so they can consider screening. Early detection allows for monitoring and can help people make informed decisions about medications, family planning, and lifestyle choices. Even if someone has no symptoms, knowing they have PLD allows them to avoid medications or situations that might worsen the condition.[4]
Genetic counseling can be valuable for families affected by PLD. A genetic counselor can help you understand the inheritance pattern, assess risk for family members, discuss the pros and cons of genetic testing, and provide guidance about family planning options for those who wish to avoid passing the condition to their children.[6]
While there’s no specific diet proven to prevent PLD cyst growth, maintaining overall liver health through a balanced diet, regular exercise, avoiding excessive alcohol, and maintaining a healthy weight is always beneficial. Some research suggests that certain medications, like somatostatin analogs, may slow cyst growth in people with existing PLD, though these are not typically used for prevention in asymptomatic individuals.[3]
