Rhabdomyosarcomas are fast-growing cancers that grow in the muscle tissues anywhere in the body. These tumors develop during childhood. All rhabdomyosarcomas are cancerous (malignant).
Rhabdomyosarcomas can develop anywhere, but the head and neck, genital or urinary tract, and limbs are the most common locations.
Symptoms depend on where rhabdomyosarcomas develop.
Diagnosis involves imaging tests and a biopsy.
Treatment consists of chemotherapy, surgery, and sometimes radiation therapy.
(See also Overview of Childhood Cancer.)
About 350 to 400 cases of rhabdomyosarcoma occur in children in the United States each year. This cancer accounts for 3% of all cancers in children under 15 years of age. Most children are diagnosed before age 10. Sometimes the tumors occur in adolescent males. Rhabdomyosarcomas occur mostly in children but can occur in adults.
This cancer develops from cells that would normally develop into muscle cells. The cause of rhabdomyosarcoma is unknown.
Although rhabdomyosarcoma can occur almost anywhere, it tends to occur most often in the following:
Head and neck (in about 35 to 40% of cases)
Genital or urinary tract (in about 25% of cases)
Limbs (in about 15 to 20% of cases)
Trunk or other miscellaneous sites (in about 20 to 25% of cases)
Rhabdomyosarcoma can spread (metastasize) to other parts of the body that are not muscles, but it is usually diagnosed before the cancer has spread. About 15% of children are diagnosed after the cancer has spread. In these children, the cancer is most commonly found in the bones, bone marrow, or lungs.
Symptoms of Rhabdomyosarcoma
Children do not typically have symptoms such as fever, night sweats, or weight loss, which are common in other cancers. In most children, the first symptom of rhabdomyosarcoma is a firm lump or problems related to an organ affected by the cancer, such as the following:
Eyes: Tearing, eye pain, cross-eyes (strabismus), problems seeing, or a bulging eye
Nose and throat: Nasal congestion, a change in the voice, or a nasal discharge that contains mucus and pus
Urinary tract: Abdominal pain, a lump in the abdomen that can be felt, difficulty urinating, and blood in the urine
Genital tract: Discharge from the vagina that contains mucus and blood or a polyp-like mass that sticks out of the vagina
Genital tract: Painless mass near a testis in the scrotum
Limbs: Firm lumps on the arms or legs
The cancers frequently spread to lymph nodes. Early spread to the lungs, bone marrow, and lymph nodes usually does not cause symptoms.
Diagnosis of Rhabdomyosarcoma
Magnetic resonance imaging (MRI) or computed tomography (CT)
Removal of tumor or biopsy
Other imaging tests
If rhabdomyosarcoma is suspected based on a doctor's examination, the child undergoes an MRI scan. Sometimes doctors may do a CT scan instead of or in addition to an MRI scan.
Doctors confirm the diagnosis by surgically removing the tumor (when possible) or by taking a sample of the tumor and examining it under a microscope (biopsy).
Doctors also do genetic tests of the tumor's cells.
To determine whether the cancer has spread, doctors do a computed tomography (CT) scan of the chest or a special type of positron emission tomography scan (PET-CT or PET-MRI).
Doctors sometimes do a spinal tap (lumbar puncture) to look for cancer cells in a sample of cerebrospinal fluid. They may also remove a sample of bone marrow to look for cancer cells (see Bone Marrow Examination).
Sometimes doctors do an FDG-PET scan to look for cancer cells in the body. For this scan, doctors inject a small amount of a radioactive tracer called fluorodeoxyglucose (FDG) into a person's body. The tracer is absorbed by cancer cells, and the more tracer the cells absorb, the more radiation they give off. The PET scanner then detects and records the radiation given off by the cancer cells. From these recordings, computers produce a series of 2- or 3-dimensional color images that look like slices of the body (called tomographs). Doctors then review the images for cancer.
Treatment of Rhabdomyosarcoma
Chemotherapy
Sometimes surgery
Sometimes radiation therapy
(See also Cancer Treatment Principles.)
Treatment consists of chemotherapy combined with surgery, radiation therapy, or both.
All children are treated with chemotherapy. The most common chemotherapy medications used are vincristine, dactinomycin, cyclophosphamide, doxorubicin, ifosfamide, and etoposide. Topotecan and irinotecan may also be used.
When surgery can be done, doctors remove the entire tumor if possible.
Children are treated with radiation if some cancer remains after surgery or if the cancer is considered intermediate risk or high risk based on its location, size, extent of spread, and specific gene mutations and on the child's age.
Prognosis for Rhabdomyosarcoma
The prognosis is based on several factors:
Where the cancer is located
How much of the cancer can be removed
Whether it has spread
How old the child is
Specific gene mutations of the tumor
Children are considered low risk, intermediate risk, or high risk depending on their combination of factors. About 90% of children whose cancer is low risk survive for at least 5 years, and about 20% of children whose cancer is high risk survive for at least 5 years.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.
American Cancer Society: How to Cope if Your Child Has Cancer
Drug Information for the Topic
