What is Rhabdomyosarcoma?
Rhabdomyosarcoma is a rare cancer that forms in the body’s soft tissues, such as muscle and connective tissue. In rhabdomyosarcoma, the cancer cells look similar to immature muscle cells. Rhabdomyosarcoma can occur at any age, but it most often affects children and young adults. Rhabdomyosarcoma most commonly forms in the:
- Head and neck
Where rhabdomyosarcoma begins and the characteristics of the cells involved in the cancer helps determine your treatment options. Treatment options for rhabdomyosarcoma include chemotherapy, surgery and radiation therapy. 
There are two main types of pediatric rhabdomyosarcoma: embryonal rhabdomyosarcoma and alveolar rhabdomyosarcoma.
- Embryonal rhabdomyosarcoma (ERMS) occurs most often in children under 10 years old and is found in the head, neck, urinary tract, or reproductive organs. It is the most common type.
- Alveolar rhabdomyosarcoma (ARMS) is more aggressive, occurs more commonly in teens or young adults, and usually starts in the torso, arms, or legs.
Rhabdomyosarcoma is the most common soft tissue cancer in children, with approximately 350 new cases each year in the United States. 
Signs and Treatments
Signs and symptoms may be caused by childhood rhabdomyosarcoma or by other conditions. The signs and symptoms that occur depend on where the cancer forms. Check with your child’s doctor if your child has any of the following:
- A lump or swelling that keeps getting bigger or does not go away. It may be painful.
- Bulging of the eye.
- Trouble urinating or having bowel movements.
- Blood in the urine.
- Bleeding in the nose, throat, vagina, or rectum.
Diagnostic tests and a biopsy 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, such as the chest. 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.
- 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. Apathologist views the bone marrow, blood, and bone under a microscope to look for signs of cancer.
- Lumbar puncture : A procedure used to collect cerebrospinal fluid (CSF) from the spinal columnto check for cancer cells. This is done by placing a needle between two bones in the spine and into the spinal column to remove a sample of CSF. This procedure is also called an LP or spinal tap.
If these tests show there may be a rhabdomyosarcoma, a biopsy is done. A biopsy is the removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. Because treatment depends on the type of rhabdomyosarcoma, biopsy samples should be checked by a pathologist who has experience in diagnosing rhabdomyosarcoma.
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 needle biopsy : The removal of tissue using a wide needle. This procedure may be guided using ultrasound, CT scan, or MRI.
- Open biopsy : The removal of tissue through an incision (cut) made in the skin.
The following tests may be done on the sample of tissue that is removed:
- Light 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 : A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
- Immunocytochemistry : A test that uses antibodies to check for certain antigens in a sample of cells. The antibody is usually linked to a radioactive substance or a dye that causes the cells to light up under a microscope. This type of test may be used to tell the difference between different types of soft tissue sarcoma.
- Reverse transcription -polymerase chain reaction (RT-PCR) test: A laboratory test in which cells in a sample of tissue are studied using chemicals to look for certain changes in the structure or function of genes.
- 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.
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 width of the tumor when the cancer was diagnosed.
- Whether the tumor has spread to nearby lymph nodes or distant parts of the body.
- Whether there are certain changes in the genes.
- The type of rhabdomyosarcoma.
- Whether the tumor has been completely removed by surgery.
- Whether the tumor responds to radiation therapy.
- The patient’s age and general health.
- Whether the tumor has just been diagnosed or has recurred (come back).
For patients with recurrent cancer, prognosis and treatment depend on the following:
- Where in the body the tumor recurred (came back).
- Whether the tumor was treated with radiation therapy.
- The size of the tumor when the cancer was diagnosed.
- How much time passed between the end of cancer treatment and when the cancer recurred.
-via Mayo Clinic Rhabdomyosarcoma Definition
 -via St. Baldrick’s Foundation
 -via http://www.cancer.gov/