Childhood rhabdomyosarcoma is a disease in which malignant (cancer) cells form in muscle tissue.

Rhabdomyosarcoma is a type of sarcoma. Sarcoma is cancer of soft tissue (such as muscle), connective tissue (such as tendon or cartilage ), and bone. Rhabdomyosarcoma usually begins in muscles that are attached to bones and that help the body move. Rhabdomyosarcoma is the most common type of sarcoma found in the soft tissues of children. It can occur in many places in the body.

There are three main types of rhabdomyosarcoma:

• Embryonal: This type occurs most often in the head and neck area or in the genital or urinary organs. It is the most common type.
• Alveolar: This type occurs most often in the arms or legs, chest, abdomen, or genital or anal areas. It usually occurs during the teen years.
• Anaplastic: This type rarely occurs in children.

See the following PDQ treatment summaries for more information about sarcomas:

• Childhood Soft Tissue Sarcoma
• Ewing Family of Tumors
• Adult Soft Tissue Sarcoma

Certain genetic conditions increase the risk of childhood rhabdomyosarcoma.

Anything that increases the 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. Parents who think their child may be at risk should discuss this with the child’s doctor. Risk factors for rhabdomyosarcoma include having the following inherited diseases:

• Li-Fraumeni syndrome.
• Neurofibromatosis type 1 (NF1).
• Beckwith-Wiedemann syndrome.
• Costello syndrome.
• Noonan syndrome.

In most cases, the cause of rhabdomyosarcoma is not known.

A possible sign of childhood rhabdomyosarcoma is a lump or swelling that keeps getting bigger.

Lumps and other symptoms may be caused by childhood rhabdomyosarcoma. The symptoms that occur depend on where the cancer forms. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• A lump or swelling that keeps getting bigger or does not go away. It may be painful.
• Bulging of the eye.
• Headache.
• Trouble urinating or having bowel movements.
• Blood in the urine.
• Bleeding in the nose, throat, vagina, or rectum.

Tests that examine the area of the body with symptoms are used to detect (find) and diagnose childhood rhabdomyosarcoma.

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-ray: An x-ray of the organs and bones inside the body. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the abdomen or pelvis, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• 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).
• Bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
• Lumbar puncture: A procedure used to collect cerebrospinal fluid (CSF) from the spinal column to check for cancer cells. This is done by placing a needle into the spinal column. This procedure is also called an LP or spinal tap.
• Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The biopsy is done after imaging tests are done. If rhabdomyosarcoma is found, the pathologist will determine the type. Because treatment depends on the type of rhabdomyosarcoma, patients should ask to have biopsy samples checked by a pathologist who has experience in diagnosing rhabdomyosarcoma.
• Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone. Samples are removed from both hipbones. A pathologist views the bone marrow, blood, and bone under a microscope to look for signs of cancer.
• 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.
• Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.

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

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

• Where in the body the tumor started.
• The size of the tumor at the time of diagnosis.
• Whether the tumor can be completely removed by surgery.
• Whether the tumor has spread to lymph nodes or distant parts of the body.
• The type of rhabdomyosarcoma.
• The patient’s age and general health.
• Whether the tumor has just been diagnosed or has recurred (come back).