Soft tissue sarcoma is a rare type of cancer that begins in the tissues that connect, support and surround other body structures. This includes muscle, fat, blood vessels, nerves, tendons and the lining of your joints.

More than 50 subtypes of soft tissue sarcoma exist. Some types are more likely to affect children, while others affect mostly adults. These tumors can be difficult to diagnose because they may be mistaken for many other types of growths.

Soft tissue sarcoma can occur anywhere in your body, but the most common types occur in the arms and legs, and in the abdomen. Surgical removal is the most common treatment, although radiation and chemotherapy also may be recommended — depending on the size, type, location and aggressiveness of the tumor.

A soft tissue sarcoma may not cause any signs and symptoms in its early stages. As the tumor grows, it may cause:

• A noticeable lump or swelling
• Pain, if a tumor presses on nerves or muscles

When to see a doctor

Make an appointment with your doctor if you have:

• A lump that is increasing in size or becomes painful
• A lump of any size that's located deep within a muscle
• Recurrence of a lump that's been removed

In most cases, it's not clear what causes soft tissue sarcoma.

In general, cancer occurs when cells develop errors (mutations) in their DNA. The errors make cells grow and divide out of control. The accumulating abnormal cells form a tumor that can grow to invade nearby structures and the abnormal cells can spread to other parts of the body.

The type of cell that develops the genetic mutation determines what type of soft tissue sarcoma you have. For example, angiosarcoma begins in the lining of blood vessels, while liposarcoma arises from fat cells. Some types of soft tissue sarcoma include:

• Angiosarcoma
• Dermatofibrosarcoma protuberans
• Epithelioid sarcoma
• Gastrointestinal stromal tumor (GIST)
• Kaposi's sarcoma
• Leiomyosarcoma
• Liposarcoma
• Malignant peripheral nerve sheath tumor
• Myxofibrosarcoma
• Rhabdomyosarcoma
• Solitary fibrous tumor
• Synovial sarcoma
• Undifferentiated (pleomorphic sarcoma)

Factors that may increase your risk of sarcoma include:

• Inherited syndromes. A risk of soft tissue sarcoma can be inherited from your parents. Genetic syndromes that increase your risk include hereditary retinoblastoma, Li-Fraumeni syndrome, familial adenomatous polyposis, neurofibromatosis, tuberous sclerosis and Werner syndrome.
• Chemical exposure. Being exposed to certain chemicals, such as herbicides, arsenic and dioxin, may increase the risk of soft tissue sarcomas.
• Radiation exposure. Previous radiation treatment for other cancers can increase the risk of soft tissue sarcomas.

Because there are so many different types of soft tissue sarcoma, it's important to determine the exact nature of each tumor so that the best treatments can be chosen.

Imaging tests

To evaluate the area of concern, your doctor might employ:

• X-rays
• Computerized tomography scans
• Magnetic resonance imaging
• Positron emission tomography

Biopsy

If a soft tissue sarcoma is suspected, it's often best to seek care at a medical center that sees many people with this type of cancer. Experienced doctors will select the best biopsy technique to ensure proper surgical treatment and planning. Options include:

• Core needle biopsy. Tiny tubes of tumor material can be obtained by this method. Doctors typically try to take samples from several sections of the tumor.
• Surgical biopsy. In some cases, your doctor might suggest surgery to obtain a larger sample of tissue or to simply remove a small tumor entirely.

In the lab, a doctor trained in analyzing body tissues (pathologist) examines the tissue sample for signs of cancer. The pathologist also analyzes the sample to understand the type of cancer and to determine whether the cancer is aggressive.

Your treatment options for soft tissue sarcoma will depend on the size, type and location of your tumor.

Surgery

Surgery is a common treatment for soft tissue sarcoma. Surgery generally involves removing the cancer and some healthy tissue surrounding it.

When soft tissue sarcoma affects the arms and legs, radiation and chemotherapy may be considered to shrink the tumor to avoid amputation.

Radiation therapy

Radiation therapy involves treating cancer with high-powered beams of energy. Options include:

• Before surgery. Radiation before surgery can help shrink the tumor so that it's easier to remove.
• During surgery. Intraoperative radiation allows a higher dose of radiation to be delivered directly to the target area, while sparing surrounding tissues.
• After surgery. Postoperative radiation can help kill any remaining cancer cells.

Chemotherapy

Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. Chemotherapy can be administered by pill or through a vein (intravenously). Some forms of soft tissue sarcoma respond better to chemotherapy than do others. For instance, chemotherapy is often used to treat rhabdomyosarcoma.

Targeted drug treatment

Some types of soft tissue sarcoma have specific characteristics in their cells that can be attacked via targeted drug treatments. These medicines work better than chemotherapy and aren't nearly as toxic. Targeted treatments have been particularly helpful in gastrointestinal stromal tumors (GISTs).

A diagnosis of cancer can be overwhelming. With time you'll find ways to cope with the distress and uncertainty of cancer. Until then, you may find it helps to:

• Learn enough about sarcoma to make decisions about your care. Ask your doctor about your soft tissue sarcoma, including your treatment options and, if you like, your prognosis. As you learn more about soft tissue sarcoma, you may become more confident in making treatment decisions.
• Keep friends and family close. Keeping your close relationships strong will help you deal with your soft tissue sarcoma. Friends and family can provide the practical support you'll need, such as helping take care of your house if you're in the hospital. And they can serve as emotional support when you feel overwhelmed by cancer.
• Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful.

If your family doctor suspects you have soft tissue sarcoma, you'll likely be referred to a cancer doctor (oncologist) who specializes in sarcomas. Soft tissue sarcoma is fairly rare and is best treated by someone who has experience with it, often at an academic or specialized cancer center.

What you can do

• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Make a list of all medications, vitamins or supplements that you're taking.
• Ask a family member or friend to come with you. Sometimes it can be difficult to remember all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.

Preparing a list of questions in advance can help you make the most of your time with your doctor. List your questions from most important to least important in case time runs out. For cancer, some basic questions to ask your doctor include:

• Do I have cancer?
• Are there other possible causes for my symptoms?
• What kinds of tests do I need to confirm the diagnosis? Do these tests require any special preparation?
• What type of sarcoma do I have?
• What stage is it?
• What treatments are available, and which do you recommend?
• Can the cancer be removed?
• What types of side effects can I expect from treatment?
• Are there any alternatives to the primary approach that you're suggesting?
• I have other health conditions. How can I best manage these conditions together?
• Are there any dietary or activity restrictions that I need to follow?
• What's my prognosis?
• Are there any brochures or other printed material that I can take with me? What websites do you recommend?
• Should I get additional treatments such as chemotherapy or radiation therapy either before or after an operation?
• Is the surgeon you're recommending experienced in this specific type of cancer operation?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may make time to cover other points you want to discuss. Your doctor may ask:

• When did you first notice your signs and symptoms?
• Are you experiencing pain?
• Does anything seem to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Do you have any family history of cancer? If so, do you know what type of cancer?