Rhabdomyosarcoma is the 3rd most common extra–central nervous system solid cancer in children Overview of Pediatric Cancer Overall, childhood cancer is relatively rare. In 2021 in the US, an estimated 10,500 children aged 0 to 14 years will be diagnosed with cancer and slightly over 1100 children will die of it... read more (after Wilms tumor Wilms Tumor Wilms tumor is an embryonal cancer of the kidney composed of blastemal, stromal, and epithelial elements. Genetic abnormalities have been implicated in the pathogenesis, but familial inheritance... read more and neuroblastoma Neuroblastoma Neuroblastoma is a cancer arising in the adrenal gland or less often from the extra-adrenal sympathetic chain, including in the retroperitoneum, chest, and neck. Diagnosis is confirmed by biopsy... read more ). About 400 to 500 cases occur in the US each year. Nonetheless, it accounts for only 3% of all childhood cancers (1 General reference Rhabdomyosarcoma is a childhood cancer arising from embryonal mesenchymal cells that have potential to differentiate into skeletal muscle cells. It can arise from almost any type of muscle tissue... read more ). Rhabdomyosarcoma belongs to a group of tumors known as soft-tissue sarcomas and is the most common cancer in this group.
Two thirds of cancers are diagnosed in children < 7 years of age. The disease is more common among whites than blacks (largely because frequency is lower in black girls) and is slightly more common among boys than girls.
There are 2 major histologic subtypes:
Embryonal: Characterized by loss of heterozygosity on chromosome 11p15.5
Alveolar: Associated with translocation t(2;13), which fuses the PAX3 gene with the FOXO1 (FKHR) gene, and t(1;13), which fuses the PAX7 gene with the FOXO1 (FKHR) gene
Although rhabdomyosarcoma can occur almost anywhere in the body, the cancer has a predilection for several sites:
Head and neck region (about 35%), usually in the orbit or nasopharyngeal passages: Most common among school-aged children
Genitourinary system (about 25%), usually in the bladder, prostate, or vagina: Usually occurring in infants and toddlers
Extremities (about 20%): Most common among adolescents
Trunk/miscellaneous sites (about 20%)
About 15 to 25% of children present with metastatic disease. The lung is the most common site of metastasis; bone, bone marrow, and lymph nodes are other possible sites.
Symptoms and Signs of Rhabdomyosarcoma
Children do not typically have systemic symptoms such as fever, night sweats, or weight loss. Usually, children present with a firm, palpable mass or with organ dysfunction due to impingement on the organ by the cancer.
Orbital and nasopharyngeal cancers may cause tearing, eye pain, or proptosis. Nasopharyngeal cavity cancers may cause nasal congestion, a change in voice, or mucopurulent discharge.
Genitourinary cancers cause abdominal pain, a palpable abdominal mass, difficulty urinating, and hematuria.
Extremity cancers appear as firm, indiscrete masses anywhere on the arms or legs. Regional lymph node spread occurs frequently, and metastases in the lungs, bone marrow, and lymph nodes can occur and usually do not cause symptoms.
Diagnosis of Rhabdomyosarcoma
CT or MRI
Biopsy or excision
Masses are evaluated by CT, although head and neck lesions are often better defined by MRI. Diagnosis of rhabdomyosarcoma is confirmed by biopsy or excision of the mass.
The standard metastatic evaluation includes chest CT, positron emission tomography (PET)–CT, bone scan, and bilateral bone marrow aspiration and biopsy.
Prognosis for Rhabdomyosarcoma
Prognosis is based on
Cancer location (eg, prognosis is better with nonparameningeal head/neck and nonbladder/nonprostate genitourinary cancers)
Completeness of resection
Presence of metastasis
Age (prognosis is worse for children < 1 year of age or > 10 years of age
Histology (embryonal histology is associated with a better outcome than alveolar histology)
Combinations of these prognostic factors place children in a low-risk, intermediate-risk, or high-risk category. A complex risk stratification system exists (see the National Cancer Institute's stage information for childhood rhabdomyosarcoma). Treatment intensifies with each risk category, and overall survival ranges from > 90% in children with low-risk disease to < 50% in children with high-risk disease.
Treatment of Rhabdomyosarcoma
Surgery and chemotherapy
Radiation therapy for residual bulk or microscopic disease
Treatment of rhabdomyosarcoma consists of surgery, chemotherapy, and sometimes radiation therapy.
Complete excision of the primary cancer is recommended when it can be done safely. Because the cancer is responsive to chemotherapy and radiation therapy, aggressive resection is discouraged if it may result in organ damage or dysfunction.
Children in all risk categories are treated with chemotherapy; the most commonly used drugs are vincristine, actinomycin D (dactinomycin), cyclophosphamide, doxorubicin, ifosfamide, and etoposide. Topotecan and irinotecan are newer drugs that have activity against this cancer.
Radiation therapy is generally reserved for children with residual bulk disease or microscopic residual tumor after surgery and for children with intermediate-risk or high-risk disease.
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Cancer Institute: Stage information for childhood rhabdomyosarcoma
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