Rhabdomyosarcoma is a fast-growing cancer that can develop in soft tissues (such as muscle) almost anywhere in the body.
Rhabdomyosarcomas account for 3 to 4% of cancers in children. Two thirds of these cancers are diagnosed in children younger than 7 years. The cancer is slightly more common among boys than girls and is more common among whites than blacks, mainly because it is less common among black girls.
This cancer develops from cells that would normally develop into muscle cells. The cause is unknown.
Although rhabdomyosarcoma can occur almost anywhere, it tends to occur in the following:
Rhabdomyosarcoma can spread (metastasize) to other parts of the body. But it is usually diagnosed before the cancer has spread.
In most children, the first evidence of the cancer is a firm lump or problems related to an organ affected by the cancer, such as the following:
Limb cancers frequently spread, especially to the lungs, bone marrow, and lymph nodes. Usually, this spread does not cause symptoms.
If a lump is detected, computed tomography (CT) or sometimes magnetic resonance imaging (MRI) is done. The diagnosis is confirmed by taking a sample from the lump and examining it under a microscope (biopsy). Sometimes the entire lump is removed.
To determine whether the cancer has spread, CT of the chest and a bone scan (radionuclide scanning of bones—see see Radionuclide Scanning) are done, and a sample of bone marrow is removed and examined.
Treatment consists of surgery, chemotherapy, and sometimes radiation. The entire cancer is removed if possible. All children are treated with chemotherapy (most commonly, vincristine, actinomycin D, cyclophosphamide, doxorubicin, ifosfamide, and etoposide).
Radiation therapy is typically used if some cancer remains after surgery or if the cancer is considered high risk. Risk (and likelihood of a good outcome) depends on the following:
Last full review/revision January 2009 by David N. Korones, MD