- A malignant tumor that starts in muscle. Rhabdomyosarcoma is primarily a childhood tumor and occurs most often in children under 5 years of age. Over 60% of cases show up before age 10. On rare occasions, rhabdomyosarcoma affects adults. Rhabdomyosarcoma can begin anywhere there is muscle including (in order of frequency) the head and neck, arms and legs, genitourinary tract, and the trunk. Treatment for rhabdomyosarcoma may involve surgery, radiotherapy or chemotherapy. Usually two or three of these modalities of treatment are employed. For example, a surgeon may first try to remove as much tumor as possible. Then the patient may undergo several weeks of chemotherapy, possibly followed by radiation therapy, and then more chemotherapy. The prognosis (outcome) with rhabdomyosarcoma depends on the location of the cancer, how far it has spread, the type of rhabdomyosarcoma, how much can be surgically removed, and the type of treatment received.
* * *A malignant neoplasm derived from skeletal (striated) muscle, occurring in children or, less commonly, in adults; classified as embryonal alveolar (composed of loose aggregates of small round cells) or pleomorphic (containing rhabdomyoblasts). SYN: rhabdosarcoma. [rhabdo- + G. mys, muscle, + sarkoma, sarcoma]- embryonal r. malignant neoplasm occurring in children, consisting of loose, spindle-celled tissue with rare cross-striations, and arising in many parts of the body in addition to skeletal muscles.
* * *rhab·do·myo·sar·co·ma 'rab-(.)dō-.mī-ə-sär-'kō-mə n, pl -mas also -ma·ta -mət-ə a malignant tumor composed of striated muscle fibers
* * *n.a rare malignant tumour, usually of childhood, originating in, or showing the characteristics of, striated muscle. Pleomorphic rhabdomyosarcoma occurs in late middle age, in the muscles of the limbs. Embryonal rhabdomyosarcomas, affecting infants, children, and young adults, are classified as botryoid (in the vagina, bladder, ear, etc.), embryonal (most common in the head and neck, particularly the orbit); and alveolar (at the base of the thumb). The pleomorphic and alveolar types respond poorly to treatment; botryoid tumours are treated with a combination of radiotherapy, surgery, and drugs. The embryonal type, if treated at an early stage, can often be cured with a combination of radiotherapy and drugs (including vincristine, dactinomycin, and cyclophosphamide).
* * *rhab·do·myo·sar·co·ma (rab″do-mi″o-sahr-koґmə) [rhabdo- + myo- + sarcoma] a highly malignant tumor of striated muscle derived from primitive mesenchymal cells and exhibiting differentiation along rhabdomyoblastic lines, including but not limited to the presence of cells with recognizable cross striations. It occurs in three forms: pleomorphic r., alveolar r., and embryonal r. Called also rhabdomyoblastoma and rhabdosarcoma.
Medical dictionary. 2011.