Liposarcoma

Liposarcoma is a rare type of cancer that starts in the fat cells. It most often begins as a growth of cells in the belly or in the arm and leg muscles. But liposarcoma can begin in the fat cells anywhere in the body.

Types & Stages

There are four basic types of liposarcoma. 

• Well-differentiated liposarcoma (WDLS). This is the most common type, accounting for 30 to 50 percent of all liposarcomas. These are slow-growing painless tumors. They may appear in your arms and legs or your trunk. Providers may call them atypical lipomatous tumors. When you have a liposarcoma in the back of your abdomen/belly (retroperitoneum), it’s called a well-differentiated liposarcoma.
   
• Myxoid liposarcoma/round cell liposarcoma. These are the second most common types of liposarcoma, accounting for about 30 percent of all liposarcomas. Unlike other types, myxoid liposarcoma may affect people ages 35 to 55. Tumors in this type of liposarcoma usually develop in the legs. It can spread to nearby soft tissue, including muscle and skin. You can also have this liposarcoma type in your bones, such as your pelvic bones or spine, or organs such as your heart, lungs or esophagus. The term “round cell” refers to how tumor cells appear when viewed under a microscope. Round cell liposarcomas account for more than 5 percent of liposarcomas and are an aggressive form of liposarcoma.
   
• Dedifferentiated liposarcoma (DDLS). Some people with WDLS develop dedifferentiated liposarcoma. Unlike WDLS, this is usually a fast-growing tumor. DDLS typically appears in the back of the belly, but may also affect the arms and legs. 
   
• Pleomorphic liposarcoma. The least common form, accounting for 5 to 10 percent of all liposarcomas, it usually appears in people’s arms and legs, but can start in the back of the belly or chest wall. Pleomorphic liposarcoma grows very fast, often spreading to the lungs. This type of liposarcoma has the worst survival rate.

Signs & Symptoms

Liposarcoma symptoms depend on the part of the body where the cancer forms. 

• Liposarcoma in the arms and legs can cause:
  • a growing lump of tissue under the skin
  • pain
  • swelling
  • weakness of the affected limb
     
• Liposarcoma in the belly, also called the abdomen, can cause:
  • abdominal pain
  • abdominal swelling
  • feeling full sooner when eating
  • constipation
  • blood in stool

Diagnosis

Tests and procedures used to diagnose liposarcoma include:

• Imaging tests. They might help show the size of the liposarcoma and include:
   
  • X-rays. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film.
     
  • Computerized tomography scan (CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. 
     
  • Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
     
  • Positron emission tomography scan (PET scan). An imaging test that uses a radioactive drug called a tracer—most often injected into a vein in your hand or arm—to show both typical and atypical metabolic activity. The PET images are typically combined with CT or MRI and are called PET-CT or PET-MRI scans. 
     
• Biopsy. A procedure to remove some cells for testing. The sample might be removed with a needle put through the skin. Or the sample might be taken during surgery to remove the cancer. The type of biopsy depends on the cancer's location.

Treatment

Treatments for liposarcoma include:

• Surgery. The goal of surgery is to remove all of the cancer cells. Whenever possible, surgeons work to remove the entire liposarcoma without damaging any surrounding organs. If a liposarcoma grows to involve nearby organs, removal of the entire liposarcoma may not be possible. In those situations, your health care team may recommend other treatments to shrink the liposarcoma. That will make it easier to remove during an operation. 
   
  • Limb-sparing surgery. This is the standard is surgery to remove the tumor without amputation. A tissue graft or an implant may be used to replace the removed tissue. This might be followed by radiation therapy.
     
• Radiation therapy. Radiation therapy uses powerful energy beams to kill cancer cells. The energy can come from X-rays, protons or other sources. Radiation may be used after surgery to kill any cancer cells that remain. Radiation also may be used before surgery to shrink a tumor to make it more likely that surgeons can remove the entire tumor.
   
• Chemotherapy. Chemotherapy uses strong medicines to kill cancer cells. Some chemotherapy medicines are given through a vein and some are taken in pill form. Not all types of liposarcoma are sensitive to chemotherapy. Careful testing of your cancer cells can show whether chemotherapy is likely to help you.

Causes & Risk Factors

It's not clear what causes liposarcoma but there are some risk factors including: 

• Gender. Liposarcoma typically affects more men than women. 
   
• Age. It’s often found in men between ages 50 and 65, except for myxoid liposarcoma, which may affect people age 35 to 55. 
   
• Radiation therapy. Exposure for cancer treatment.
   
• Workplace chemicals. Exposure to workplace chemicals such as vinyl chloride.

Screening

There is no routine screening for liposarcoma.