From the Guidelines
Embryonal rhabdomyosarcoma is a rare and aggressive type of soft tissue cancer that primarily affects children, characterized by cells that appear similar to developing muscle cells in a 7-10 week old embryo, and is typically treated with a multimodal approach including surgery, chemotherapy, and radiation therapy. This cancer most commonly occurs in the head and neck region, particularly around the eyes or in the nasal passages, but can also develop in the urinary tract, reproductive organs, arms, or legs 1. The disease occurs due to genetic mutations that affect normal muscle development, though most cases are not hereditary but occur spontaneously during cell division. Some key points to consider about embryonal rhabdomyosarcoma include:
- It is a type of rhabdomyosarcoma, which is classified into several subtypes, including embryonal, alveolar, and pleomorphic 1
- The embryonal subtype typically occurs in children and young adults, while the pleomorphic subtype typically occurs in older adults 1
- The FOXO1-PAX3/7 gene fusion confers a poorer prognosis and is frequently found in alveolar rhabdomyosarcoma, but not in embryonal rhabdomyosarcoma 1
- Treatment usually involves a combination of surgery, chemotherapy, and radiation therapy, with the specific regimen depending on the tumor's location, size, and whether it has spread 1
- Early diagnosis and treatment are crucial for improving outcomes, as this cancer can grow rapidly and spread to other parts of the body 1. In terms of prognosis, survival rates in localized embryonal rhabdomyosarcoma have improved significantly in recent decades due to cooperative trial groups identifying effective multiagent systemic therapy and adequate local control, with contemporary trials reporting > 80 % survival in those with localized disease 1. However, some patients have worse prognosis, with adverse prognostic factors for localized embryonal rhabdomyosarcoma including incompletely resected tumors occurring at unfavourable sites, age 10 years or older, tumor size larger than 5 cm, and nodal involvement 1. Overall, embryonal rhabdomyosarcoma is a serious and potentially life-threatening disease that requires prompt and aggressive treatment, and patients should be managed by a multidisciplinary team of healthcare professionals, including pediatric oncologists, surgeons, and radiation oncologists 1.
From the Research
Definition and Classification
- Embryonal rhabdomyosarcoma (ERMS) is a malignant soft tissue tumor with morphologic and immunophenotypic features of embryonic skeletal muscle 2.
- Rhabdomyosarcoma is classified into histologic subtypes: embryonal, alveolar, pleomorphic, spindle, and mixed-type, with ERMS being the most common subtype in children and adolescents 3, 2.
Characteristics and Clinical Presentation
- ERMS typically includes a range of differentiation in rhabdomyoblasts from primitive to terminally differentiated forms, and the latter become more prominent after chemotherapy-induced cytodifferentiation 2.
- The disease usually exhibits worse outcomes in adults than in pediatric patients when rhabdomyosarcoma is found in adults 3.
- Clinical presentation can vary, but common symptoms include generalized musculoskeletal pain, unintended weight loss, and excessive night sweats 3.
Treatment and Management
- Recommended treatment includes surgery and chemotherapy with possible radiation therapy if deemed necessary 4.
- The chemotherapy most commonly used for treatment of embryonal RMS is a combination of vincristine, actinomycin D, and cyclophosphamide 3, 4.
- Radiotherapy is also considered a crucial component of multimodality therapy, particularly in high-risk cases, but may result in significant long-term sequelae for survivors 5.
Heterogeneity and Origin
- Single-cell transcriptional profiling has revealed the heterogeneity in embryonal rhabdomyosarcoma, with tumor cells divided into subgroups characterized by different functions and evolutionary trajectories 6.
- The origin of embryonal rhabdomyosarcoma is believed to be from skeletal muscle progenitor cells, as shown in a study of pelvic ERMS 6.