Ewing sarcoma

Background

• Highly aggressive malignant bone or soft tissue tumor arising from cells of the neuroectoderm
• One-fourth of patients will have metastasis at the time of presentation
  • It is assumed that almost all patients have subclinical metastasis
• Presence and location of metastasis is the major prognostic factor for survival
• Metastasis is most frequently seen in bone (spine most common) and lungs
• Around 70 to 80 percent survival in those with non-metastatic disease
• More common in males

Clinical Features

• Constant pain for months over site of malignancy
  • Worse with exercise and at night
• Site will be edematous and tender to palpation
  • Mass can sometimes be appreciated
• Most often found in pelvis, axial skeleton, or diaphysis of femur with a small minority arising in soft tissues
• Pelvic tumors are more regularly associated with metastatic disease
• Fever, weight loss, fatigue, night sweats occur in less than 20 percent of patients
• Pathological fractures can occur

Differential Diagnosis

Malignant

• Multiple myeloma
• Chondrosarcoma
• Paget disease
• Osteosarcoma
• Giant cell tumor
• Adamantinoma
• Chordoma
• Primary bone lymphoma
• Fibrosarcoma
• Myosarcoma
• Abscess

Benign

• Chrondroblastoma
• Enchondroma
• Langerhans cell histiocytosis of bone
• Osteoblastoma
• Osteochondroma
• Osteoid Osteoma

Evaluation

• Appearance on plain radiographs often described as “onion peel” or “moth-eaten” appearance referring to the respective periosteal bone formation and osseous destruction
• LDH is a prognostic factor
• Definitive diagnosis is made with biopsy
• Work-up often includes PET scan for metastatic disease
• t(11;22) translocation is often seen

Management

• Pain control
• Neoadjuvant and adjuvant chemotherapy
• Surgery and/or radiation therapy for local control of disease

Disposition

• Home with outpatient follow up
• Admission if necessary for pain control or significant disease burden