Key Points for This Section

Childhood soft tissue sarcoma is a disease in which malignant (cancer) cells form in soft tissues of the body. There are many different types of soft tissue sarcomas. Fibrous (connective) tissue tumors Fibrohistiocytic tumors Fat tissue tumors Smooth muscle tumors Blood and lymph vessel tumors Peripheral nervous system tumors Bone and cartilage tumors Tumors with more than one type of tissue Tumors of unknown origin (the place where the tumor first formed is not known) Having certain diseases and inherited disorders can increase the risk of developing childhood soft tissue sarcoma. The most common sign of childhood soft tissue sarcoma is a painless lump or swelling in soft tissues of the body. Diagnostic tests and a biopsy are used to detect (find) and diagnose childhood soft tissue sarcoma. Certain factors affect prognosis (chance of recovery) and treatment options.

Childhood soft tissue sarcoma is a disease in which malignant (cancer) cells form in soft tissues of the body.

Soft tissues of the body connect, support, and surround other body parts and organs. The soft tissues include the following:

• Muscles.
• Tendons (bands of tissue that connect muscles to bones).
• Synovial tissues (tissues around joints).
• Fat.
• Blood vessels.
• Lymph vessels.
• Nerves.

Soft tissue sarcoma may be found anywhere in the body. In children, the tumors form most often in the arms, legs, or trunk (chest and abdomen).

There are many different types of soft tissue sarcomas.

The cells of each type of sarcoma look different under a microscope. The soft tissue tumors are grouped based on the type of soft tissue cell where they first formed.

Rhabdomyosarcoma is the most common type of childhood soft tissue sarcoma. It begins in muscles that surround bone. Rhabdomyosarcoma is not discussed in this summary. (See the PDQ summary on Childhood Rhabdomyosarcoma Treatment ¹ for more information.) This summary is about the other types of soft tissue sarcoma:

Fibrous (connective) tissue tumors

• Fibromatoses (desmoid tumor).
• Dermatofibrosarcoma.
• Fibrosarcoma.
• Inflammatory myofibroblastic tumor.

Fibrohistiocytic tumors

• Malignant fibrous histiocytoma (also called undifferentiated pleomorphic sarcoma, or spindle cell sarcoma).

Fat tissue tumors

• Liposarcoma.

Smooth muscle tumors

• Leiomyosarcoma.

Blood and lymph vessel tumors

• Angiosarcoma.
• Lymphangiosarcoma.
• Hemangiopericytoma.
• Hemangioendothelioma.

Peripheral nervous system tumors

• Malignant schwannoma (malignant peripheral nerve sheath tumor).

Bone and cartilage tumors

• Extraosseous osteosarcoma.
• Extraosseous myxoid chondrosarcoma.
• Extraosseous mesenchymal chondrosarcoma.

Tumors with more than one type of tissue

• Malignant mesenchymoma.
• Malignant Triton tumor.
• Malignant ectomesenchymoma.

Tumors of unknown origin (the place where the tumor first formed is not known)

• Alveolar soft part sarcoma.
• Epithelioid sarcoma.
• Clear cell sarcoma (malignant melanoma of soft parts).
• Synovial sarcoma.
• Desmoplastic small round cell tumor.

Besides rhabdomyosarcomas, the most common soft tissue sarcomas in children are in joint tissue, connective tissue, and nerve tissue.

Soft tissue sarcoma occurs in children and adults. Soft tissue sarcoma in children may respond differently to treatment, and may have a better outcome than soft tissue sarcoma in adults. (See the PDQ summary on Adult Soft Tissue Sarcoma Treatment ² for more information on treatment in adults.)

Having certain diseases and inherited disorders can increase the risk of developing childhood soft tissue sarcoma.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for childhood soft tissue sarcoma include having the following inherited disorders:

• Li-Fraumeni syndrome.
• Neurofibromatosis type 1 (NF1).

Other risk factors include the following:

• Having AIDS (acquired immune deficiency syndrome) and Epstein-Barr virus infection.
• Having retinoblastoma in both eyes.
• Past treatment with radiation therapy.

The most common sign of childhood soft tissue sarcoma is a painless lump or swelling in soft tissues of the body.

A sarcoma may appear as a painless lump under the skin, often on an arm, a leg, or the trunk. There may be no other symptoms at first. As the sarcoma grows larger and presses on nearby organs, nerves, muscles, or blood vessels, symptoms may occur, including pain or weakness.

Other conditions may cause the same symptoms that soft tissue sarcomas do. A doctor should be consulted if any of these problems occur.

Diagnostic tests and a biopsy are used to detect (find) and diagnose childhood soft tissue sarcoma.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• X-rays: An x-ray is a type of energy beam that can go through the body onto film, making pictures of areas inside the body. A series of x-rays may be done to check the lump or painful area.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).

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  Magnetic resonance imaging (MRI) of the abdomen. The patient lies on a table that slides into the MRI machine, which takes pictures of the inside of the body. The pad on the patient’s abdomen helps make the pictures clearer.

If these tests show there may be a soft tissue sarcoma, a biopsy is done. One of the following types of biopsies may be used:

• Fine-needle aspiration (FNA) biopsy: The removal of tissue or fluid using a thin needle.
• Core biopsy: The removal of tissue using a wide needle.
• Incisional biopsy: The removal of part of a lump or a sample of tissue.
• Excisional biopsy: The removal of an entire lump of tissue. An excisional biopsy may be used to completely remove smaller tumors that are near the surface of the skin.

In order to plan the best treatment, a large sample of tissue may be removed during the biopsy to find out the type of soft tissue sarcoma and do laboratory tests. Tissue samples will be taken from the primary tumor, lymph nodes, and other areas that may have a tumor. A pathologist views the tissue under a microscope to look for cancer cells and to find out the type and grade of the tumor. The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the cells are dividing. High-grade tumors usually grow and spread more quickly than low-grade tumors. Because soft tissue sarcoma can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience in diagnosing soft tissue sarcoma.

One or more of the following laboratory tests may be done to study the tissue samples:

• Cytogenetic analysis: A laboratory test in which cells in a sample of tissue are viewed under a microscope to look for certain changes in the chromosomes.
• Immunohistochemistry study: A laboratory test in which dyes or enzymes are added to a blood or bone marrow sample to test for certain antigens (proteins that stimulate the body's immune response).
• Immunocytochemistry study: A laboratory test that uses different substances to stain (color) cells in a sample of tissue. This is used to tell the difference between the different types of soft tissue sarcoma.
• Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• The type of soft tissue sarcoma.
• The stage of the cancer (the amount of tumor remaining after surgery to remove it or whether the tumor has spread to other places in the body).
• The location, grade, and size of the tumor and how deep under the skin the tumor is.
• Whether or not the patient also has a condition called neurofibromatosis type 1 (NF1).
• The age of the patient.
• Whether the cancer has just been diagnosed or has recurred (come back).

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

A disease caused by the human immunodeficiency virus (HIV). People with AIDS are at an increased risk for developing certain cancers and for infections that usually occur only in individuals with a weak immune system. Also called acquired immunodeficiency syndrome.

A type of cancer that begins in the cells that line blood vessels or lymph vessels. Cancer that begins in blood vessels is called hemangiosarcoma. Cancer that begins in lymph vessels is called lymphangiosarcoma.

A substance that causes the immune system to make a specific immune response.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

Tissue removed from the body and examined under a microscope to determine whether disease is present.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A type of cancer that forms in bone cartilage. It usually starts in the pelvis (between the hip bones), the shoulder, the ribs, or at the ends of the long bones of the arms and legs. A rare type of chondrosarcoma called extraskeletal chondrosarcoma does not form in bone cartilage. Instead, it forms in the soft tissues of the upper part of the arms and legs. Chondrosarcoma can occur at any age but is more common in people older than 40 years. It is a type of bone cancer.

Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.

A type of cell that looks clear inside when viewed under a microscope.

Supporting tissue that surrounds other tissues and organs. Specialized connective tissue includes bone, cartilage, blood, and fat.

The removal of a tissue sample with a wide needle for examination under a microscope.

The study of chromosomes and chromosomal abnormalities.

A tumor of the tissue that surrounds muscles, usually in the abdomen. A desmoid tumor rarely metastasizes (spreads to other parts of the body). It may be called aggressive fibromatosis when the tumor is outside of the abdomen.

A rare, aggressive cancer that usually affects young males and usually is located in the abdomen.

The process of identifying a disease, such as cancer, from its signs and symptoms.

In medicine, a disturbance of normal functioning of the mind or body. Disorders may be caused by genetic factors, disease, or trauma.

A microscope (device used to magnify small objects) that uses electrons (instead of light) to produce an enlarged image. An electron microscope shows tiny details better than any other type of microscope.

A protein that speeds up chemical reactions in the body.

A common virus that remains dormant in most people. It causes infectious mononucleosis and has been associated with certain cancers, including Burkitt lymphoma, immunoblastic lymphoma, and nasopharyngeal carcinoma. Also called EBV.

A surgical procedure in which an entire lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

Located outside of the bone.

A condition in which multiple fibromas develop. Fibromas are tumors (usually benign) that affect connective tissue.

A type of soft tissue sarcoma that begins in fibrous tissue, which holds bones, muscles, and other organs in place.

The removal of tissue or fluid with a thin needle for examination under a microscope. Also called FNA biopsy.

Liquid.

The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

A type of cancer involving blood vessels and soft tissue.

When referring to cancerous and precancerous growths, a term used to describe cells that look abnormal under a microscope. These cells are more likely to grow and spread quickly than cells in low-grade cancerous and precancerous growths.

The activity of the immune system against foreign substances (antigens).

A surgical procedure in which a portion of a lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

Having to do with inflammation (redness, swelling, pain, and a feeling of heat that helps protect tissues affected by injury or disease).

Transmitted through genes that have been passed from parents to their offspring (children).

In medicine, the place where two or more bones are connected. Examples include the shoulder, elbow, knee, and jaw.

A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

A malignant (cancerous) tumor of smooth muscle cells that can arise almost anywhere in the body, but is most common in the uterus, abdomen, or pelvis.

A rare, inherited predisposition to multiple cancers, caused by an alteration in the p53 tumor suppressor gene.

A rare cancer of the fat cells.

When referring to cancerous and precancerous growths, a term used to describe cells that look nearly normal under a microscope. These cells are less likely to grow and spread quickly than cells in high-grade cancerous or precancerous growths.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.

A type of cancer that begins in the cells that line lymph vessels.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

A rare, fast-growing tumor of the nervous system or soft tissue that occurs in children and young adults. Malignant ectomesenchymomas may form in the head and neck, abdomen, perineum, scrotum, or limbs. Also called ectomesenchymoma.

A soft tissue sarcoma that usually occurs in the limbs, most commonly the legs, and may also occur in the abdomen. Also called malignant fibrous cytoma.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

Refers to cells that develop into connective tissue, blood vessels, and lymphatic tissue.

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.

A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.

A rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves, and developmental changes in the nervous system, muscles, bone, and skin. Also called NF1.

A part of the body that performs a specific function. For example, the heart is an organ.

A cancer of the bone that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteogenic sarcoma.

A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.

A doctor who identifies diseases by studying cells and tissues under a microscope.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

An exam of the body to check for general signs of disease.

Occurring in various distinct forms. In terms of cells, having variation in the size and shape of cells or their nuclei.

The original tumor.

The likely outcome or course of a disease; the chance of recovery or recurrence.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

To come back or to return.

Cancer that forms in the tissues of the retina (the light-sensitive layers of nerve tissue at the back of the eye). Retinoblastoma usually occurs in children younger than 5 years. It may be hereditary or nonhereditary (sporadic).

Cancer that forms in the soft tissues in a type of muscle called striated muscle. Rhabdomyosarcoma can occur anywhere in the body.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

A cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

A tumor of the peripheral nervous system that arises in the nerve sheath (protective covering). It is almost always benign, but rare malignant schwannomas have been reported.

Refers to muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body.

A cancer that begins in the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body.

A type of connective tissue cancer in which the cells are spindle-shaped when examined under a microscope.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A layer of connective tissue that lines the cavities of joints, tendon sheaths, and bursae (fluid-filled sacs between tendons and bones). The synovial membrane makes synovial fluid, which has a lubricating function.

A malignant tumor that develops in the synovial membrane of the joints.

Tough, fibrous, cord-like tissue that connects muscle to bone or another structure, such as an eyeball. Tendons help the bone or structure to move.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

A term used to describe cells or tissues that do not have specialized ("mature") structures or functions. Undifferentiated cancer cells often grow and spread quickly.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.