Write a Review
x
Feedback Orthopedics

Ewing sarcoma

  • Small cell round sarcoma

Epidemiology

  • Most common in patients 5-25 years of age; slight male preponderance
  • Second most common malignant bone tumour in children
  • Sites – pelvis, distal femur, proximal tibia, femoral diaphysis, proximal humerus

Etiology

  • Genetics – t(11;22) translocation
    • Leads to formation of fusion protein (EWS-FLI1)

Pathogenesis

  • The EWS-FLI1 fusion protein acts as an aberrant transcription factor – facilitates oncogenesis

Clinical features

  • Pain and fever (can mimic an infection)
  • Swelling
  • Local tenderness
  • Fatigue, weight loss, decreased appetite

Diagnosis

 X-ray – large destructive lesion in the diaphysis/metaphysis, with a permeative moth-eaten appearance

  • Tc99 bone scan – shows very hot lesion
  • MRI
  • CT – to look for pulmonary metastases
  • Bloods – elevated ESR, WBC, LDH
  • Immunostaining – CD99 positive in 95% of cases

Treatment

  • Chemotherapy and radiation – for non-resectable tumours
  • Chemotherapy and limb salvage resection – most common
    • For tumours that can be completely removed
    • Drugs – vincristine, doxorubicin, cyclophosphamide

Differential diagnosis

  • Other small cell round tumours
    • Neuroblastoma/leukemia <5 years
    • Lymphoma >30 years
    • Myeloma >50 years
  • Osteosarcoma
  • Osteomyelitis

Complications

  • Secondary neoplasms – bone sarcoma (from radiation); AML/MDS (from chemotherapy)
  • Recurrence/progression
  • Metastases
Feedback