Liposarcoma is a very rare type of cancer. It starts in your fat tissue. It can grow anywhere in your body. The most common places are inside your belly (abdomen), the thighs, and behind your knee. There are different types of liposarcoma based on how the cells look under a microscope.

Liposarcomas tend to show up in people between ages 50 and 65.

Experts aren't exactly sure what causes liposarcoma. But it occurs when cells in the body change and grow out of control. These abnormal cells may grow to form a lump or mass called a tumor. If the tumor is cancerous, it can grow into (invade) nearby areas. It can even spread to other parts of the body (metastasis).

A risk factor is anything that may increase your chance of having a disease. The exact cause of someone's cancer may not be known. But risk factors can make it more likely for a person to have cancer. Some risk factors may not be in your control. But others may be things you can change.

Liposarcomas tend to show up in people between ages 50 and 65. Risk factors that might raise your risk for cancers that start in the soft tissues (soft tissue sarcomas), such as liposarcoma, include:

• Certain genetic syndromes, such as neurofibromatosis and Li-Fraumeni syndrome.
• Exposure to radiation as treatment for another cancer.
• Working with certain chemicals, but this link to liposarcoma isn't clear.

Talk with your doctor about your risk factors for liposarcoma and what you can do about them.

Liposarcoma most often starts in the legs or in the retroperitoneum (back of the abdomen). In most cases, it doesn't cause symptoms early on. Sometimes a lump can be seen or felt under your skin. It grows slowly and is often not painful at first.

Liposarcoma often doesn't cause symptoms until the cancer has grown for some time. Symptoms depend on where the tumor is and how big it is. Tumors in the belly can get big before they cause problems.

As the tumor grows, symptoms may include:

• Painful swelling or numbness in the area around your lump.
• A new lump anywhere on your body or an existing lump that keeps growing.

As the tumor grows, liposarcoma in the belly can cause:

• Black, bloody, or tarry stool.
• Blood in your vomit.
• Stomach pain or cramping.
• Abdominal swelling.

Many of these may be caused by other health problems. But it's important to see your doctor if you have these symptoms. Only a doctor can tell if you have cancer.

Your doctor will ask you about your health history, symptoms, risk factors, and family history of disease. A physical exam will be done.

You may also need one or more of these tests:

• Imaging tests. These can find a tumor. They can also show the extent of your cancer and how far it's spread. They may include X-rays, an MRI, a CT scan, or an ultrasound.
• Biopsy. A biopsy is the only way to confirm cancer. It's either done by surgery or with a needle and syringe. Small pieces of tissue are taken out and checked in a lab for cancer cells.

After a diagnosis of liposarcoma, you'll likely need other tests. These help your doctors learn more about the cancer. They can help determine the stage of cancer. The stage is how much and how far the cancer has spread (metastasized) in your body. It's one of the most important things to know when deciding how to treat the cancer.

After your cancer is staged, your doctor will talk with you about what the stage means for your treatment. Ask your doctor to explain the stage of your cancer.

Your treatment choices depend on the type of liposarcoma you have, test results, where the tumor is, the size of the tumor, and the stage of the cancer. The goal of treatment may be to cure you, control the cancer, or to help ease problems caused by cancer. Talk with your care team about your treatment choices, the goals of treatment, and what the risks and side effects may be.

Types of treatment for cancer are either local or systemic. Local treatments remove, destroy, or control cancer cells in one area. Surgery and radiation are local treatments. Systemic treatment is used to destroy or control cancer cells that may have traveled around your body. When taken by pill or injection, chemotherapy is a systemic treatment. You may have just one treatment or a combination of treatments.

Treatment for liposarcoma may include:

• Surgery. This is the most common treatment. Surgery is done to take out the tumor and a healthy edge of tissue around it.
• Radiation. This treatment may be used before surgery to try to shrink the tumor so it can be removed while sparing nearby organs. If surgery can't be done, it may help kill cancer cells.
• Chemotherapy. Like radiation, this treatment helps shrink or kill cancer cells. It may be used if surgery can't be done or the cancer has spread to other parts of your body.

Talk with your doctors about your treatment choices. Make a list of questions. Think about the benefits and possible side effects of each choice. Talk about your concerns with your doctor before making a decision. Experts are always researching new and better ways to treat cancer. Ask your doctor if there are any clinical trials you could consider.

Liposarcoma is a malignant tumor. This means it can spread to or grow into other parts of your body. These include vital organs and tissues surrounding the original tumor. If left untreated, liposarcoma can be life-threatening. Early detection and treatment are very important.

Liposarcoma is often tricky to spot. See your doctor right away if you notice a new or unusual lump underneath your skin or anywhere on your body. You should also see your doctor if you have any of the other symptoms.

• Liposarcoma is a very rare type of cancer. It starts in your fat tissue.
• Having certain genetic syndromes raises a person's risk for this cancer.
• Liposarcoma often doesn't cause symptoms early on. But sometimes a painless lump that can be seen or felt develops under the skin.
• A biopsy is often needed to diagnose liposarcoma.
• Surgery is the most common treatment.
• Liposarcoma can spread and be life-threatening if left untreated.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours or on weekends.