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Undifferentiated Embryonal Sarcoma of the Liver (UESL)

Article Translations: (Spanish)

What Is Undifferentiated Embryonal Sarcoma of the Liver (UESL)?

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare kind of liver cancer that happens mostly in children.

What Are the Signs & Symptoms of Undifferentiated Embryonal Sarcoma of the Liver (UESL)?

Many children with UESL have no symptoms. Others may have one or more of these signs: 

  • a lump in the belly, or a bigger belly than usual
  • belly pain
  • a loss of appetite
  • vomiting
  • diarrhea
  • constipation
  • fever 
  • tiredness
  • weight loss
  • trouble breathing

What Does "Undifferentiated Embryonal Sarcoma" Mean?

  • "Undifferentiated" means that the cells making up the cancer don't look like any kind of specialized cell, such as a liver cell, muscle cell, or fat cell.
  • "Embryonal" means that the cancer probably grew from cells early in a fetus' development that didn't change (differentiate) into liver cells properly.
  • "Sarcoma" means it's a type of cancer that grows from the kind of cell that forms connective tissue (cells that connect or support other kinds of tissue in the body).

What Causes Undifferentiated Embryonal Sarcoma of the Liver (UESL)?

Doctors don't know what causes UESL.

Who Gets Undifferentiated Embryonal Sarcoma of the Liver (UESL)?

Most children who get undifferentiated embryonal sarcoma of the liver are 6 to 10 years old. Sometimes older children and adults get UESL.

How Is Undifferentiated Embryonal Sarcoma of the Liver (UESL) Diagnosed?

When a child has symptoms that suggest UESL, the doctor will do an exam and order tests such as:

  • blood tests, including liver and kidney function tests
  • imaging tests:
    • ultrasound
    • X-rays
    • computed tomography (CT or CAT scan)
    • magnetic resonance imaging (MRI)
  • biopsy (removing a small piece of tissue using surgery or a needle with imaging)

Doctors study the biopsy sample to see if the tissue is a tumor . If it is, the biopsy also can show the type of liver tumor. Knowing the tumor type helps them know which treatments are most likely to work well.

How Is Undifferentiated Embryonal Sarcoma of the Liver (UESL) Treated?

Doctors usually use a combination of different treatments for UESL, such as:

  • surgery to remove the tumor from the liver
  • a liver transplant if the tumor cannot be removed with surgery
  • chemotherapy (treatment with medicines to shrink the tumor)
  • transarterial radioembolization with Yttrium-90 (TARE-Y90), which delivers a high dose of radiation therapy directly into the tumor(s)
  • bland embolization, which uses small particles to shut off the blood supply to the tumor
  • tumor ablation , which kills tumors using small needles to heat or cool them

Who Treats Undifferentiated Embryonal Sarcoma of the Liver (UESL)?

Undifferentiated embryonal sarcoma of the liver is treated by a health care team, including specialists in:

  • oncology (cancer)/hematology (blood diseases)
  • surgery
  • interventional radiology (image-guided minimally invasive procedures)
  • gastroenterology (digestive tract) and hepatology (liver)
  • pathology (diagnosing diseases by examining body tissues, fluids, and organs )
  • genetics (genetic counseling and genetic testing)
  • radiology (medical imaging)
  • nutrition

What Else Should I Know?

UESL tends to grow quickly, but treatment for this cancer is improving. 

If your child has UESL, work with the care team to get the best treatment. This may mean frequent doctor's visits, hospital stays, medical tests, and treatments with side effects.

Talk to the care team about any questions or concerns that you have about the treatment plan. They can help you and your child with the physical and emotional challenges that come with treatment.

After treatment, the doctor will do a checkup every year to see if the cancer has come back and to help take care of any side effects from treatment.

You also can find information and support online at:

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Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

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