What is rhabdomyosarcoma?
Rhabdomyosarcoma is a cancerous tumor that originates in the soft tissues of the body, including the muscles, tendons, and connective tissues. The most common sites for this tumor to be found include the head, neck, bladder, vagina, arms, legs, and trunk. Rhabdomyosarcoma can also be found in places where skeletal muscles are absent or very small, such as in the prostate, middle ear, and bile duct system. The cancer cells associated with this disease can spread (metastasize) to other areas of the body.
Embryonal rhabdomyosarcoma, the most common type, usually occurs in children under 6 years of age. Alveolar rhabdomyosarcoma occurs in older children and is less common.
Rhabdomyosarcoma accounts for about 3 percent of childhood cancers. In the U.S., about 350 children are diagnosed with rhabdomyosarcoma each year. This disease mostly affects children under the age of 10, but can occur at any age. For unknown reasons, males are affected slightly more often than females.
Prevention & Risk Assessment
What causes rhabdomyosarcoma?
It is believed that some rhabdomyosarcoma tumors begin developing in the fetus. Rhabdomyoblasts are the cells at the initial stages of development of an unborn baby. These cells will mature and develop into muscles. There has been much research into the gene structure of these rhabdomyoblasts and possible detection of a gene error that can produce the disease later in development.
Rhabdomyosarcomas usually have some type of chromosome abnormality in the cells of the tumor, which are responsible for the tumor formation. In children with an embryonal rhabdomyosarcoma, there is usually an abnormality of chromosome 11. In alveolar rhabdomyosarcoma, a rearrangement in the chromosome material between chromosomes 2 and 13 is usually present. This rearrangement changes the position and function of genes, causing a fusion of genes referred to as a fusion transcript. Patients have an abnormal fusion transcript involving two genes known as PAX3 and FKHR. This important discovery has led to improvements in diagnosing rhabdomyosarcoma.
Rhabdomyosarcomas are also more common in children with neurofibromatosis or Li-Fraumeni syndrome, which are genetic disorders. Li-Fraumeni syndrome is a clustering of soft tissue and other cancers in a family caused by mutations in a tumor suppressor gene called p53, which results in uncontrolled cell growth.
There has been no association between rhabdomyosarcoma and environmental exposures.
What are the symptoms of rhabdomyosarcoma?
The following are the most common symptoms of rhabdomyosarcoma. However, each child may experience symptoms differently. Many symptoms depend on the size and the location of the tumor. Symptoms may not be present until the tumor is very large, especially if it is located deep in the muscle or in the stomach. Symptoms may include:
- A tumor or mass that can be seen or felt (may or may not be painful)
- Bleeding from the nose, vagina, rectum, or throat (may occur if the location of the tumor is in these areas)
- Tingling, numbness, pain, and movement may be affected if the tumor compresses nerves in the area
- Protrusion of the eye or a drooping eyelid (may indicate a tumor behind the eye)
The symptoms of rhabdomyosarcoma may resemble other conditions or medical problems. Always consult your child’s doctor for a diagnosis.
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