Ewing's sarcoma is a highly aggressive malignant tumor that primarily affects bone and soft tissue, most frequently occurring in children and adolescents
. It is the second most common bone tumor in this age group
Pathology and diagnosis
- Histology: Ewing's sarcoma is characterized by small round cells expressing high levels of CD99
- Genetics: The tumor is defined by balanced chromosomal translocations, most commonly involving the EWSR1 and FLI1 genes, resulting in the EWSR1-FLI1 fusion protein
- Biopsy and pathology: Guidelines recommend obtaining molecular testing to distinguish Ewing's sarcoma from other round cell sarcomas . A biopsy is recommended in the initial work-up of patients with suspected primary bone sarcoma . Cytogenetics and/or molecular testing may be required, potentially necessitating re-biopsy
Clinical presentation
- Ewing's sarcoma most commonly affects the long bones, pelvis, and chest
- It can also occur in rare locations such as the cervical epidural region and the calvarial bone in elderly patients
Management
- Local / locoregional disease: Treatment options include surgery, radiotherapy, and chemotherapy. Complete surgical excision is preferred when feasible . If complete surgical excision is not possible, radiotherapy with definitive intent alone may be offered . Chemotherapy regimens may include vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide
- Advanced / metastatic disease: In patients with metastatic disease, local treatment is attempted, especially in the presence of responding metastatic disease . Wide excision or definitive radiotherapy and chemotherapy are recommended for local control of the primary site
Prognosis
- The prognosis for Ewing's sarcoma varies. The survival rate is 70–80% for patients with standard-risk and localized disease but drops to approximately 30% for those with metastatic disease
In conclusion, Ewing's sarcoma is a highly aggressive malignant tumor primarily affecting bone and soft tissue in children and adolescents. It is characterized by specific genetic translocations and small round cells expressing CD99. Management involves a combination of surgery, radiotherapy, and chemotherapy, with prognosis varying based on the extent of the disease at diagnosis.