Myxoid/round cell liposarcoma, or MRCLS, is one of several types of liposarcoma. Liposarcoma is a rare cancer that grows in the cells that store fat in the body. MRCLS usually grows in the arms and legs. These tumors grow slowly, and they can spread to other parts of the body.

Each year in the United States, about 2,000 people are diagnosed with liposarcoma. MRCLS is one of the most common types of liposarcoma and makes up about 30% of all liposarcoma cases. It is more common in people aged 20 to 40 years old and is rarely seen in children under 10 years old.

Many people with MRCLS do not have symptoms when the cancer first starts. Later, when the tumor gets larger, symptoms can include:

• A visible lump under the skin
• Pain
• Tiredness
• Nausea
• Unintentional weight loss

Imaging: If you have symptoms of MRCLS, your doctor will use imaging scans such as CT and MRI to look at where the tumor is and how big it is. They will also check for signs that the tumor has spread to other parts of the body.

Biopsy: To check if the tumor is MRCLS, your doctor will do a biopsy, taking a small sample from the tumor with a needle. An expert, called a pathologist, will study cells from the sample under the microscope to see what kind of tumor it is.

Treatment for each patient will be unique. You should go to an expert in liposarcoma treatment to decide the best approach for your tumor. You can contact MyPART for help finding experts near you.

Treatment options to discuss with your doctor include:

Surgery: Surgery is often used to remove the main tumor while trying to avoid removing any healthy tissue.

Radiation therapy: Radiation therapy can be used around the time of surgery. The radiation is used to shrink the tumor so it can be removed by surgery. Radiation therapy can also be used after surgery if there is concern that tumor cells remain after surgery.

Chemotherapy: For cases that are difficult to treat by surgery or when the cancer has spread, chemotherapy can be used to treat liposarcoma.

MRCLS is not known to run in families. When you have MRCLS, you may have other conditions that increase your chance of getting cancer. Genetic conditions such as Li-Fraumeni syndrome and neurofibromatosis may increase your risk of getting liposarcoma.

We do not yet know what causes MRCLS to form. Scientists are always working to understand how cancer forms, but it can be hard to prove. We know that in most cases of MRCLS, a chromosome (the part of your cells that contains your genes) breaks apart and gets put back together in the wrong way. This can cause cells to not function like they should. In MRCLS, a gene called FUS joins with a gene called CHOP. This happens in almost all cases, so it may be very important for how MRCLS forms. Scientists are trying to understand how this works, so they can invent new therapies.

The estimate of how a disease will affect you in the long term is called prognosis. Every person is different, and prognosis will depend on many factors, such as:

• Where the tumor is in your body
• If the cancer has spread to other parts of your body
• How much of the tumor was taken out during surgery

If you want information on your prognosis, it is important to talk to your doctor. Also, NCI has resources to help you understand cancer prognosis.

The 5-year survival rate for patients with MRCLS that is small and has not spread to other parts of the body is over 80%. Follow-up care is necessary to make sure the tumor does not grow back or spread to other parts of the body. However, prognosis for patients with MRCLS that has spread to other parts of the body tends to be poor.