Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Ewing Sarcoma

Basics
Description
  • Ewing sarcoma is a malignant bone tumor of the long bones, pelvis, and spine usually seen in childhood.
  • Bone pain is the most common finding.
  • Fever and an elevated white blood cell count and ESR sometimes are found.
  • Nerve root irritation may be noted in patients with spinal lesions.
  • It most commonly involves the diaphysis or metaphysis of long bones.
  • Classification:
    • Classified according to the system of the Musculoskeletal Tumor Society (known as the Enneking system)
    • Most are stage II-B (high-grade, extracompartmental tumors), but up to 20-25% of children present with lung or bone metastases.
  • Synonym: Round cell sarcoma
Epidemiology
Incidence
  • The second most common malignant bone tumor of childhood, after osteosarcoma
  • Affects males more often than females
  • Is most common in persons <25 years old but rarely occurs in children <3 years old
  • Rare in non-Caucasion individuals
Risk Factors
Genetics
Reciprocal translation t(11;22)(q24;q12) [fusion transcription factor EWS/FL1-1 product]
 
Etiology
The causes of this tumor are not known.
 
Diagnosis
Signs and Symptoms
  • A localized mass with pain and tenderness for several weeks or months is common.
  • The patient often presents with systemic symptoms of fever, malaise, and weight loss.
  • Occasionally, the tumor is associated with a pathologic fracture.
Physical Exam
  • In the early course of the disease, the physical examination is normal.
  • As the soft-tissue component of the tumor grows, a soft-tissue mass may be palpated.
Tests
Lab
  • Complete blood count
  • Electrolyte determinations
  • ESR
  • Bone marrow aspiration and biopsy:
    • Biopsy of the soft-tissue portion of the lesion (if present) avoids the need to penetrate the bone.
Imaging
  • Plain radiographs are indicated.
    • Often show a large lytic lesion that usually affects the diaphysis or metaphysis of long bones (frequently the fibula)
    • May show a variable amount of reactive new bone formation
    • May show a periosteal reaction, with a characteristic onion skin appearance
    • May show tumor invading the soft tissue
    • May appear normal in the early stage of the disease
  • Patients with lesions suspected of being Ewing sarcoma should undergo staging studies, including:
    • MRI of the primary lesion
    • Chest radiography
    • Chest CT
    • Bone scanning
    • Bone marrow aspiration
Pathological Findings
  • Numerous small, round cells are blue on hematoxylin and eosin staining.
  • The uniform, densely packed cell population has scant cytoplasm.
  • The outlines of cells and nuclei are indistinct and may appear out of focus.
  • Special immunochemical stains are used to confirm the diagnosis (e.g., HBA-71).
Differential Diagnosis
  • Most commonly confused with osteomyelitis
  • Histologically similar to:
    • Metastatic neuroblastoma (especially in patients <5 years old)
    • Lymphoma (especially in patients <5 years old)
    • Rhabdomyosarcoma
  • One must also consider EOG and metastatic disease (especially in patients >30 years old).
  • If the patient is <5 years old, lymphoma and metastatic neuroblastoma must be excluded.
Treatment
General Measures
  • Multiagent chemotherapy and external beam irradiation
  • Wide surgical resection in certain cases, especially when the bone is expendable, such as the fibula, iliac wing, and clavicle
Special Therapy
Radiotherapy
External beam irradiation can be used definitively for local control or as an adjunct to surgery.
 
Physical Therapy
Physical therapy is used to maintain ROM and muscle strength.
 
Medication
Drugs of choice are various chemotherapeutic agents, according to the most current protocols.
 
Surgery
  • Surgery has become an important modality for achieving local control.
  • If surgery is indicated, a wide surgical margin is necessary.
  • Limb salvage is performed in almost all cases.
Follow-up
Prognosis
  • 5-year survival of 60-70% with current treatment
  • Less favorable outcome with tumors in the pelvis or spine
Complications
  • Postirradiation sarcomas may occur 2-5 years after external beam irradiation.
  • After treatment with chemotherapy and external beam irradiation:
    • Fracture: The proximal femur is the most at-risk bone.
    • Osteonecrosis of the hip in patients with pelvic or proximal femur lesions
Patient Monitoring
  • Metastasis:
    • May develop in 30-40% of patients (4)
    • Pulmonary:
      • CT scans are obtained every 3-4 months for 2-3 years, then every 6 months up to 5 years, annually thereafter
    • Bone:
      • Technetium bone scans are used to detect bone metastaseas and are obtained every 3-6 months for 2-3 years, then annually
  • Local recurrence:
    • May develop in 10-30% of patients treated with irradiation and chemotherapy and in 5-10% of patients treated with chemotherapy and surgery
    • MRI/CT is used when a prosthesis is not present.
    • Radiographs and serial physical examinations are used for patients with prosthetic devices.
Miscellaneous
Codes
ICD9-CM
170.9 Ewing sarcoma
 
Patient Teaching
  • Patients and family members are taught the importance of systemic chemotherapy to prevent metastasis.
  • Protected weightbearing is important during induction chemotherapy.
  • Compliance with posttreatment surveillance is necessary to monitor for metastasis and local recurrence.
FAQ
Q: Is surgery better for local control than radiation therapy?
A: Surgery to remove the tumor has the advantage of a better local control rate, and it obviates the risk of a postirradiation sarcoma. Compared with chemotherapy, surgical resection may not be associated with a survival benefit.
 
Q: Can patients still be cured if they present with metastatic disease?
A: Although the prognosis is much worse for such patients, 10-25% can still be cured.

1 comment to Ewing Sarcoma

  • Terry Nosis

    Hello!! Dr Kevin. I’ve been diagnosed with Ewing Sarcoma and needed treatment at your hospital. What would be the cost of it. Thanks!