Myxoid Liposarcoma

Myxoid liposarcoma (MLPS) is a type of liposarcoma, a group of rare cancers that begin in fat cells. You can have this condition for years before having symptoms, like a lump under the skin on your legs or arms.

Most myxoid liposarcoma tumors grow slowly. That said, high-grade tumors often spread to nearby soft tissue, like muscle and skin. The cancer can also spread to organs or bones, like your pelvis or spine.

Another name for high-grade MLPS is myxoid round cell liposarcoma. It gets its name from the round cells that healthcare providers see when they look at the cancer cells under a microscope.

Providers most often use surgery and radiation therapy to treat tumors that haven’t spread (localized disease). You may need cancer drugs that travel throughout your body, like chemotherapy, to treat MLPS that has spread (metastases).

Symptoms of myxoid liposarcoma

The most common sign is a slow-growing lump under your skin. Usually, it’s in the deep tissue in your leg (especially your thigh) or arms. Tumors can also form in your chest, abdomen or pelvis. Sometimes, large tumors cause symptoms, such as:

• Pain
• Fatigue
• Nausea
• Unintended or unexplained weight loss

Myxoid liposarcoma causes

This condition happens when part of one chromosome breaks off and attaches to a different chromosome. This causes a fusion gene to form. The mix-up turns normal cells into cancer cells that form tumors. There are two main types of fusion genes linked to MLPS:

• FUS::DDIT3, found in about 95% of cases
• EWSR1::DDIT3, found in about 5% of cases

Your provider will look for these genes to confirm your diagnosis.

Healthcare providers don’t know what causes the gene mix-up in the first place. They do know that most people diagnosed are between 30 and 50. But it can affect people of all ages.

How doctors diagnose this condition

Your provider will do a physical exam and ask about your symptoms. Tests they may use include:

• CT scan: CT scans help providers locate tumors and assess tumor size.
• MRI: MRI scans help providers check on nearby nerves, blood vessels and muscles that a liposarcoma may affect. You may get a whole-body MRI to look for metastases.
• Biopsy: Providers take tumor tissue samples to check for cancer cells.
• Molecular and gene testing: These tests look for the fusion genes linked to myxoid liposarcoma.

Staging and grading

Healthcare providers stage myxoid liposarcoma to see how advanced it is. They use the TNM staging system. It considers things like the tumor’s size and whether disease has spread to your lymph nodes or distant organs.

Grading is especially important. Providers assign a grade to the cancer based on how the cells look under a microscope. High-grade cancers are likely to spread.

Myxoid liposarcoma is high-grade if more than 5% of the cancer cells in a biopsy sample are round cells. Once, providers thought of “round cell liposarcoma” as a different cancer type. Now, it’s considered an aggressive form of myxoid liposarcoma.

How do healthcare providers treat myxoid liposarcoma?

Your provider may use one or a combination of the following treatments:

• Surgery: A surgeon removes the tumor and surrounding healthy tissue, including microscopic tumor cells. This is the main treatment when it’s localized disease (it hasn’t spread).
• Radiation therapy: Providers often use radiation therapy to shrink a myxoid liposarcoma before surgery removes it. You may also have this treatment after surgery to reduce the risk of cancer coming back.
• Chemotherapy: Healthcare providers may use chemotherapy to treat tumors that surgery can’t remove or that have spread. Sometimes, they use it to shrink tumors before surgery.
• Targeted therapy: This treatment targets cancer cell weaknesses tied to their gene mutations. It’s a newer form of treatment that your provider may use to treat advanced disease.

When should I see my healthcare provider?

You’ll need regular check-ups even if treatment sends disease into remission. Remission means there aren’t any signs or symptoms of cancer. This is because tumors can come back as new tumors where cancer first started. Sometimes, they show up in a different area of your body.

How often you’ll need follow-ups depends on the tumor grade or stage. Usually, they’re more frequent within the first three years. This is when the chances of tumors coming back are highest.

What can I expect if I have this condition?

In general, people who get treatment for localized disease have a better outlook than people with tumors that have spread. Other things that often forecast a better prognosis include:

• Being younger than 45
• Tumors smaller than 10 centimeters
• Tumors with no round cells
• Negative margins after surgery (no signs of cancer cells)

Your healthcare provider is your best resource for information about what you may expect, given your situation.

Can myxoid liposarcoma be cured?

It can be placed in remission, meaning treatment eliminates all signs and symptoms of myxoid liposarcoma. But it may come back.

Your healthcare provider will monitor you closely, so they can detect recurrence early, when treatments work best.

What is the survival rate for myxoid liposarcoma?

According to a recent study, the five-year survival rate of MLPS is 79%. The 10-year survival rate is 66%. This means that nearly 8 out of 10 people are alive five years after their diagnosis, and a little fewer than 7 in 10 are alive 10 years later.

It’s important to remember that survival rates are estimates. Experts develop survival rate estimates by reviewing the experiences of others with the same condition. What’s true for those people may not be true for you. Also, these numbers don’t account for important differences, like cancer stage and grade.

Your healthcare provider is the best resource for understanding your timeline.