Liver cysts are abnormal sacs in the liver that may contain fluid or a solid mass of cells. Usually, liver cysts do not cause symptoms or require any treatment.
Sometimes, however, if the cysts become large, a person may experience pain or other symptoms that require treatment.
In this article, we explore the causes, symptoms, and complications of liver cysts and when to see a doctor. We also cover diagnosis and treatment and what cystic tumors are when these occasionally occur.
Cysts that grow in the liver are often congenital. This term means that the cysts formed before birth, while a person was developing in the womb.
Liver cysts can also occur at any point during a person’s life for reasons scientists have yet to discover. According to a 2015 study, women are more likely to develop liver cysts than men.
Infection with an Echinococcus tapeworm can also lead to liver cysts. These parasites are often present in farm animals or animals that live on farms, which can include dogs, wolves, and coyotes. A person can become infected with Echinococcus through exposure to the feces of these animals.
Infection with Echinococcus is known as hydatid disease, cystic hydatid disease, or echinococcosis. This condition can also cause cysts in the lungs, kidneys, brain, and other organs around the body.
Polycystic liver disease (PLD) is another condition that can cause liver cysts. PLD is a rare genetic condition, which means that it runs in families.
People with PLD develop multiple cysts throughout their lives, but the condition often causes no symptoms. Many individuals with PLD also have polycystic kidney disease.
Other causes of liver cysts include liver cancer and injury to the liver.
According to the 2015 study, only around 5–10 percent of liver cysts cause symptoms. These symptoms tend to first occur in people who are aged 60 years or older.
Symptoms of liver cysts can include:
- distended or protruding stomach
- feelings of abdominal fullness or bloating
- abdominal pain, particularly in the upper right quadrant
- nausea and vomiting
- shoulder pain
These symptoms usually occur when a cyst starts bleeding. If a cyst becomes large enough, a person may be able to feel it through their abdomen
Rarely, liver cysts can multiply or grow so large that they begin to affect the function of nearby organs. For example, a very large cyst may obstruct the vena cava, a major vein that carries blood back to the heart. In this instance, a doctor may recommend surgery to remove the cyst or cysts.
Liver cysts are usually benign, which means they are not cancerous. However, around 5 percent of liver cysts are cystic tumors.
Very rarely, these cystic tumors can become malignant and can spread beyond the liver. Because of this, doctors will usually recommend surgery to remove a cystic tumor completely.
Anyone who is having symptoms that could indicate a liver cyst may wish to speak to their doctor. Seeking immediate medical attention is necessary if the pain is severe.
Because liver cysts often cause no symptoms, people usually only discover they have them while undergoing an imaging test for something else.
They might also recommend a blood test to determine if a person has an Echinococcus infection.
Most people with liver cysts do not require treatment unless they are experiencing symptoms.
If liver cysts are causing problems, a doctor may drain the cyst by inserting a fine needle through the abdomen. However, this is usually only a temporary treatment as the fluid can return over time.
The most effective treatment for liver cysts is surgical removal. Surgeons can usually remove the cyst using a laparoscopic approach, which involves making only 2 or 3 small incisions into the abdomen. After removal, cysts are unlikely to return.
A doctor may prescribe antibiotics for people with an Echinococcus infection.
In rare instances, a person with PLD or polycystic kidney disease may require a liver or kidney transplant if their condition is causing life-threatening symptoms.
Scientists are also researching medications, such as somatostatin analogs, to treat and manage liver cysts without surgery.
Around 5 percent of liver cysts are cystic tumors, which are abnormal growths that have the potential to become cancerous over time. However, most cystic tumors are benign, and only around 5 percent of them become malignant.
Although cystic tumors usually do not cause symptoms, it can be difficult to distinguish between a potentially cancerous tumor and one that is harmless, or benign.
A doctor may order a biopsy to determine if a cystic tumor might be potentially malignant. However, they will often recommend that a person has surgery to completely remove a cystic tumor and ensure that they do not become cancerous.
Liver cysts are uncommon and rarely cause symptoms. However, if they become large, they can sometimes cause pain and swelling in the abdomen, plus other symptoms. If a liver cyst is causing problems, a doctor may recommend surgery to remove the cyst.