A cyst on the liver, also called a hepatic cyst, is a small fluid-filled sac that is in the liver. Small cysts are usually not associated with symptoms, however large or ruptured cysts can lead to right-sided abdominal pain, abdominal swelling or nausea.

This type of cyst is more common in women, and may be present from birth due to a malformation of the bile ducts. They can also form in adulthood due to parasitic infections or from using contraceptives.

Liver cysts generally do not require treatment, but in many cases, a hepatologist or general practitioner may monitor it over time. In more serious cases that present with intense symptoms, the doctor may advise surgical removal of the cyst.

Main symptoms

The main symptoms of a liver cyst are:

Abdominal pain on the right side, below the right rib
Abdominal swelling
Weight loss
Nausea or vomiting
Feeling of a full belly
Fever above 38ºC (or 100.4ºF)
Yellow skin and eyes
Excessive fatigue

Some cases may present with additional symptoms such as coughing up blood, itching throughout the body, severe abdominal pain and right shoulder pain. However, in general, a liver cyst does not cause symptoms, and is only identified after routine exams.

If you experience these symptoms, you should consult a hepatologist or general practitioner to confirm a diagnosis and start treatment as needed.

Confirming a diagnosis

A hepatologist or family doctor will typically diagnose a cyst on the liver by evaluating both symptoms and the results of imaging tests, such as an ultrasound, CT scan or MRI.

The doctor may also order blood tests, like ALT and AST, or antigen tests, to rue out parasitic infections.

Types of liver cysts

Liver cysts can be classified according to their cause, the main ones being:

Simple cyst: This is the most common type of cyst that tends to be present from birth and is generally smaller than 4 cm in size. It generally does not cause symptoms.
Hydatid cyst: This type of cyst is caused by parasites, such as echinococcus, which are transmitted through contaminated food and water.
Neoplastic cyst: This is the rarest type of liver cyst that can be benign or malignant. Examples include cystadenoma or cystadenocarcinoma. They generally appear in clusters and are large in size.

The type of cyst on the liver can usually be identified through imaging tests.

Possible causes

The exact cause of a cyst on the liver is not known, however, several cases have been observed in which the cyst is present since birth, due to a malformation of the bile ducts. Genetic mutations passed down from your parents can also cause polycystic liver disease.

Furthermore, liver cysts can also form gradually through the lifespan. They can appear due to parasitic infections, or from using medications like oral contraceptives or anabolic steroids.

When is a liver cyst dangerous?

Most of the time, a liver cyst is not serious and is also not a sign of cancer. However, cysts that appear to increase in size over time are considered to be more clinically significant.

Liver cysts that are of a benign neoplastic type, such as cystadenoma, are associate with a greater risk of becoming malignant (cystadenocarcinoma), which can leading to liver cancer. In this case, the doctor may surgical removal of the cyst.

Treatment options

Treatment for a cyst on the liver should be guided by a hepatologist or general practitioner. It depends on the type of cyst and its underlying cause. Simple cysts that do not present with any symptoms and are under 4 cm in size may not need any specific interventions. The doctor may advise ongoing monitoring, every 3 to 12 months, to detect any cyst growth.

Cysts on the liver that cause symptoms may be surgically removed through percutaneous aspiration or laparoscopy. When malignancy is suspected, the surgeon can remove the cyst, collect a sample of the fluid and send it for analysis to determine whether cancerous cells are present.

If the biopsy comes back positive for cancer, treatment may also include further surgery to remove part of the liver, chemotherapy, radiation therapy or, in some cases, a liver transplant.