Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents, arising from primitive mesenchymal cells that are committed to skeletal muscle differentiation. The disease can occur virtually anywhere in the body, but the most common primary sites include the head and neck region (including the orbit and parameningeal areas), the genitourinary tract (bladder, prostate, vagina, paratesticular region), and the extremities. The two major histological subtypes are embryonal rhabdomyosarcoma (including the botryoid variant), which is more common in younger children, and alveolar rhabdomyosarcoma, which tends to occur in older children and adolescents and is often associated with characteristic chromosomal translocations involving PAX3-FOXO1 or PAX7-FOXO1 fusion genes. Key symptoms depend on the tumor location and may include a visible or palpable mass, swelling, pain, proptosis (bulging of the eye) for orbital tumors, nasal obstruction or bloody discharge for nasopharyngeal tumors, urinary obstruction or hematuria for genitourinary tumors, and cranial nerve palsies for parameningeal tumors. Metastatic disease can involve the lungs, bone marrow, bones, and lymph nodes. Diagnosis is established through biopsy with histopathological examination, immunohistochemistry (positive for desmin, myogenin, and MyoD1), and molecular testing for characteristic translocations. Treatment for rhabdomyosarcoma is multimodal and typically involves a combination of chemotherapy, surgery, and radiation therapy. Risk-stratified treatment protocols, developed through cooperative group trials (such as those by the Children's Oncology Group and the European Paediatric Soft Tissue Sarcoma Study Group), assign patients to low-, intermediate-, or high-risk groups based on histological subtype, stage, resectability, and molecular features. Standard chemotherapy regimens include vincristine, actinomycin D, and cyclophosphamide (VAC). Prognosis varies significantly by risk group, with 5-year survival rates exceeding 70% for localized embryonal tumors but remaining considerably lower for metastatic or alveolar subtypes with unfavorable fusion status. Research into targeted therapies and immunotherapy approaches is ongoing.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Rhabdomyosarcoma