Soft tissue sarcomas in children can appear in muscle, fat, fibrous tissue, blood vessels, tendons, connective tissues, or other supporting tissues of the body. Rhabdomyosarcoma accounts for about half of the cases of pediatric soft tissue sarcomas. Less frequent pediatric soft tissue sarcomas include fibrosarcoma, mesenchymoma, synovial sarcoma, and liposarcoma.
Rhabdomyosarcoma tumors arise from a cell called a “rhabdomyoblast,” which is a primitive muscle cell. Instead of differentiating into striated muscle cells, the rhabdomyoblasts grow out of control. Since this type of muscle is located throughout the body, the tumors can appear at numerous locations. The four major sites in which rhabdomyosarcoma occurs and their relative occurances are:
- head and neck; around the eyes, or orbital (35-40%)
- genitourinary tract (20%)
- extremities (15-20%)
- trunk (chest and lungs) (10-15%)
Rhabdomyosarcoma is classified according to the histology of the cells (how they look under a microscope):
- Embryonal: The most common type, usually found in children under 15 years of age and in the head and neck region and genitourinary tract.
- Botryoid: A variant of the embryonal type; the tumor arises as a grape-like lesion in mucosal-lined hollow organs such as the vagina and urinary bladder.
- Alveolar:A more aggressive tumor that usually involves the muscles of the extremities or trunk, more common in adolescents.
- Pleomorphic:Rarely seen in children; arises in muscles of the extremities.
Embryonal orbital and genitourinary track rhabdomyosarcomas have a better prognosis than do tumors that originate in the head and neck, extremity, pelvic, and trunk locations. The prognosis is also affected by the age of the child, whether or not the tumor can be completely removed by surgery, and whether it has metastasized.
- More information on rhabdomyosarcoma on the NCI web site – note that you can toggle back and forth between “Health Professional” and “Patient” versions.
Other Types of Soft Tissue Sarcomas
Non-rhabdomyosarcoma soft tissue sarcomas are classified according to the type of soft tissue that they resemble. The NCI web site discusses these cancers on the following pages:
- Childhood soft-tissue sarcomas (patient version, you can toggle to the health professional version)
- Soft tissue sarcomas questions and answers
Treatment for rhabdomyosarcoma usually includes surgery to remove the tumor, multi-agent chemotherapy, and radiation. The most common chemotherapy is called VAC (vincristine, actinomycin-D, and cyclophosphamide).
The treatment plan depends on whether the rhabdomyosarcoma is considered low, intermediate, or high risk. Risk classifications depend on the type of cancer cell (e.g., embryonal, botryoid, or alveolar) and whether the cancer can be removed completely with surgery or has spread to other parts of the body (rhabdomyosarcoma stage information).
Clinical trials for rhabdomyosarcoma and for soft tissue sarcomas can be found by searching the clinical trial database on the NCI web site. Follow these directions:
- Start at the NCI clinical trials search page.
- Choose type of cancer: “rhabdomyosarcoma, child” or “soft tissue sarcoma, child”
- You will be given more choices (e.g., type of cancer and type of trial). Choose the appropriate responses and click “search. “
Symptoms of Rhabdomyosarcoma
Rhabdomyosarcoma often causes a noticeable lump on a child’s body. If the tumor is located internally, the symptoms depend on its location. For example, tumors in the nasal passage may put pressure on the eustachian tubes. A bladder tumor can cause a child to have trouble urinating. An orbital tumor may cause the eye to protrude.
Symptoms can include:
- lump or swelling, firm and painless to touch, in the extremities, the groin area, or the vaginal area
- drooping eyelids, swelling of the eye, protruding eyeball, rapid vision changes
- hoarseness, difficulty in swallowing
- abdominal pain that persists for more than a week
- Rhabdomyosarcoma accounts for 5-8% of childhood cancers.
- 70% of all rhabdomyosarcoma cases diagnosed in the first ten years of life, with the peak incidence in the 1-5 age group.
- In children with localized disease, 70% survive 5 years.
- Overall, 50% of the children diagnosed with rhabdomyosarcoma survive 5 years.
Most cases of rhabdomyosarcoma have no recognized causes or risk factors. However, a small percentage of rhabdomyosarcoma cases are associated with certain genetic conditions, including Li-Fraumeni cancer susceptibility syndrome and Beckwith-Wiedemann syndrome.
- MD Anderson Cancer Center Children’s Cancer Hospital– MD Anderson’s website contains information on the symptoms, diagnosis, and treatment of childhood cancers. You can also find information about their Childhood Cancer Survivors Clinic, clinical trials, etc.
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