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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Ewing's Sarcoma


- See: Bone Tumor Menu

- Discussion:
    - prevalence:
         - it represents approx 7% of all primary bone malignancies; 
         - second most common primary malignant bone tumor (behind osteosarcoma) (2.1 per 1 million children)
         - Ewing's sarcoma is more common in males and is rare in blacks;
    - source:
         - uncertain origin;
         - may arise from primitive reticulum cells of marrow;
         - common karyotypic translocation between chromosomes 11 and 22;
    - age:
         - it is a tumor of children & young adults, w/ most cases occurring between ages of 10 and 20 years;
         - 3% of Ewing's sarcoma occurs in children less than 3 years of age;
         - 64% of Ewing's sarcoma occur in the second decade;
    - genetics:
         - expresses p30/32 MIC2 antigen (cell surface glycoprotein);
         - 85% contain chromosomal translocation at the t(11;22)(q24;q12);
    - prognosis:
         - potentially the most lethal of all the bone tumors;
         - most important adverse prognostic factor was metastatic disease detectable at the time of diagnosis;
         - it almost always presents as a stage IIb lesion;
         - before routine use of adjuvant chemo, pts w/ Ewing's were treated w/ XRT alone, & 5 year survival rate was no more than 15%;
         - w/ use of adjuvant chemo, 5 year survival rate to more than 60%;
         - w/ non metastatic Ewing's, disease free survival is 55-70% versus 22-33% for metastatic;
         - pts require careful follow-up, due to post-XRT osteosarcoma;
         - pelvic ewing's:
               - tumors in pelvis are typically detected later & are therefore larger, with a poorer prognosis;
               - 5 year survival rate is about 25%;
    - differential diagnosis:
         - osteomyelitis, osteolytic osteosarcoma, & EOG, & neuroblastoma;
         - in infants and young children, it is necessary to rule out neuroblastoma (only 2% of patients with ewings sarcoma are less than 5 years of age);
               - ewing's sarcoma will stain positve for PAS (cytoplasmic glycogen) and will have a positive vimentin stain;
               - neuroblastoma stains negative for PAS and has a negative vimentin stain, but neuroblastoma is positive for neuron-specific enolase and neurofilament;
         - midshaft lesion w/ large, assoc soft-tissue swelling suggests either infection or Ewing's sarcoma;
         - osteogenic sarcoma tends to be more metaphyseal;
         - ref: Ewings sarcoma masquerading as osteomyelitis


- Clinical Presentation:
    - may mimic osteomyelitis w/ fever, elevated WBC, & sed rate, wt loss, anemia;
    - enlarging, tender, bony prominence w/ an associated soft tissue mass;
    - sites:
           - femoral diaphysis > pelvis, tibia,  humerus, fibula & ribs;
                  - develops in axial skeleton in large proportion of pts (about 40 %);
           - tumors in pelvis are typically detected later & are therefore larger, with a poorer prognosis;
           - lesion also has peculiar predilection for shaft of fibula
           - an area containing little or no hematopoietic marrow;
           - it occasionally arises in extraosseous sites ("soft-tissue, Ewing's").
           - distant metastases are noted at diagnosis in about 20% of cases;


- Radiographs:
    - permeative diaphyseal tumor w/ mottled, or patchy density;
    - cortical involvement may produce periosteal reaction, "onion skin" pattern;
    - references:
         - Is PET Useful in Detecting Occult Nonpulmonary Metastases in Pediatric Bone Sarcomas?


- Microscopic Features:


- Treatment:
    - treatment consists of chemotherapy, surgical resection & possible XRT;
           - w/ combined therapy pt survival has improved.
           - reference: Outcomes and Prognostic Factors for Ewing-Family Tumors of the Extremities
    - some authors recommend bone marrow aspiration and biopsy at two or more sites for staging purposes;
    - radiotherapy:
           - approx 75-85 % of primary ewing's tumors are sensitive, depending primarily on tumor size and site;
           - poor to fair results are expect w/ large tumors located in axial skeleton;
           - obviously XRT is not desirable in children because of its effect on the growing limb and because of the possibility for causing 
                     secondary tumors (can be up to 20%);
    - chemotherapy:
           - vincristine, doxorubicin, cyclophosphamide, adriamycin, ifosfamide, and etoposide;
           - addition of chemotherapy with surgery increases survival to greater than 70% at 5 years;
    - wide surgical excision:
           - preferred over XRT if:
                   - involved bone is expendable (eg fibula, rib, clavicle);
                   - if XRT would damage growth plate (XRT may cause premature closure of growth plate);
                   - if there is pathologic frx;
           - limb salvage w/ insertion of long stem tibial component:

             



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References

Tumor volume as a predictor of necrosis after chemotherapy in Ewing's sarcoma.

Local and systemic control in Ewing's sarcoma of the femur treated with chemotherapy, and locally by radiotherapy and/or surgery.

Is PET Useful in Detecting Occult Nonpulmonary Metastases in Pediatric Bone Sarcomas?



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Clifford R. Wheeless, III, MD on Monday, July 28, 2014 6:59 pm