Ewing sarcoma
Ewing sarcoma is an aggressive small round blue cell malignancy of neuroectodermal origin arising in the diaphysis of long bones or pelvic flat bones, typically in White males under 15 years, defined by the t(11;22) EWS-FLI1 fusion. It is confirmed on biopsy with cytogenetic or molecular fusion testing and is treated with multiagent chemotherapy plus local control by surgery, radiation, or both.
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What this article covers
- Overview
Aggressive pediatric small round blue cell bone malignancy: Ewing sarcoma is a malignant tumor of anaplastic small round blue cells of neuroectodermal (mesenchymal) origin, arising most often in the…
- Epidemiology
Second most common malignant pediatric bone tumor: after osteosarcoma, Ewing sarcoma is the second most common primary malignant bone tumor in children and adolescents.
- Risk factors
Age under 15 to 20 years: the tumor arises overwhelmingly in children and adolescents, with rare cases in young adults.
- Pathophysiology
EWS-FLI1 fusion oncoprotein as the driving lesion: the t(11;22)(q24;q12) translocation fuses the EWSR1 gene on chromosome 22 with the FLI1 gene on chromosome 11, producing an aberrant transcription…
- Clinical features
Progressive localized bone pain and a palpable enlarging mass is the hallmark presentation: the diagnosis is suspected clinically from progressive, often worse-at-night bone pain with an enlarging…
- Differential diagnosis
Osteomyelitis: fever, elevated inflammatory markers, and bone pain with periosteal reaction can closely mimic Ewing sarcoma radiographically and clinically; distinguish by biopsy with culture and…
- Diagnosis
Diagnosis is confirmed by biopsy demonstrating small round blue cells with the t(11;22) EWS-FLI1 fusion, obtained through an ordered first-imaging-then-biopsy sequence: first obtain plain radiographs…
- Management
First step, multidisciplinary treatment planning before any intervention: because Ewing sarcoma requires coordinated systemic chemotherapy and local control, refer to a pediatric or sarcoma oncology…
- Complications
Early metastatic spread: a strong tendency toward early hematogenous metastasis, most commonly to lungs, other bones, and bone marrow, is the dominant driver of mortality.
- Prognosis
Localized disease has a favorable long-term survival with current multimodal therapy: 5-year survival for localized, non-metastatic Ewing sarcoma treated with combined chemotherapy and local control…
- Prevention
No established primary prevention: Ewing sarcoma has no confirmed environmental, lifestyle, or heritable risk factor to modify, so there is no screening test or preventive intervention for the general or high-risk population.
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