Liposarcoma: What Is It and How Is It Treated?

Medically Reviewed By: Priscilla Merriam, MD

Cancers known as sarcomas develop in the connective tissues, such as muscle, fat, and bone, that hold the body together. Liposarcomas originate from immature fat cells that develop abnormally into cancerous fatty growth as a result of errors that can develop in its genes.  

Sarcomas are rare, accounting for about 1% of cancers in adults. There are more than 50 subtypes of sarcomas. Liposarcoma is one of the more common subtypes.

There are treatment options for sarcoma, including surgery, chemotherapy, and radiation. While metastatic liposarcoma can be challenging to treat, there are options, and researchers are focused on developing more options for patients.

What are the signs and symptoms of liposarcoma?

Liposarcomas, which most often affect middle-age and older adults, may develop as large, bulky masses inside the body. They generally cause no symptoms until they begin to affect nearby organs and structures. When they appear in the arms and legs, they are may be discovered as a result of unusual swelling, which may or may not be painful.  When they occur in the abdomen, liposarcomas may not be discovered until they begin to cause symptoms by pressing against nearby organs.

How are liposarcomas diagnosed?

Liposarcomas are diagnosed by examination of biopsied tissue. Determining which type of liposarcoma a patient has is extremely important and requires special expertise; sometimes DNA testing is also required. The type of liposarcoma determines the patient’s course of treatment.

A biopsy is always required in order to make a definitive and accurate diagnosis. Scans can give an idea of what the mass is but, a biopsy is always used to make an official diagnosis.

There are currently no known risk factors for this type of cancer, so when a patient comes in with a suspected liposarcoma, a biopsy is taken to determine whether or not the mass is a liposarcoma.

What are the types of liposarcoma?

Liposarcomas are usually classified as well-differentiated, dedifferentiated, myxoid, and pleomorphic. These four groups have different characteristics.

  • Well-differentiated liposarcomas: Well-differentiated liposarcomas appear very similar to their benign version, lipomas. To the untrained eye, a well-differentiated tumor could be mistaken for a lipoma. (Lipomas are slow growing fatty lumps that grow between the skin and the underlying muscle layer. They are benign and usually harmless.) When a liposarcoma resembles a lipoma and is located in the abdomen or the pelvis, it is called a well-differentiated liposarcoma.
  • Dedifferentiated liposarcomas: Dedifferentiated liposarcomas often occur in conjunction with well-differentiated liposarcomas. Dedifferentiated liposarcomas tend to be more aggressive than well-differentiated ones, which are usually slow growing.
  • Myxoid and pleomorphic liposarcomas: These two are biologically different from each other and from well-differentiated and dedifferentiated liposarcoma. These subtypes may behave aggressively. They each have their own distinct pattern of metastatic disease and sensitivities to chemotherapy.   

How are liposarcomas treated?

Surgery is the primary treatment for liposarcomas. Whenever possible, surgery is used to remove the entirety of the tumor. Radiation may or may not be recommended in addition to surgery for treatment of a liposarcoma that is limited to one area of the body.

If liposarcoma is located in a place where surgery is not possible or if the liposarcoma has spread to multiple areas, then medical therapies (such as chemotherapy) are considered. These therapies will not eliminate a liposarcoma, but can help manage it.

What’s the latest in research for liposarcoma?

There is significant interest in the research community in developing new treatments for liposarcoma. Research approaches include targeting the process of cell growth in liposarcoma cells, and using immunotherapy approaches. Improving treatment options for patients with liposarcoma is an important focus among sarcoma doctors and researchers.

About the Medical Reviewer

Priscilla Merriam, MDPriscilla Merriam, MD, is the clinical director of the Sarcoma Center at Dana-Farber.