Ewing sarcoma is the third most common bone malignancy in children and adolescents. It arises from mesenchymal stem cells and most commonly affects the long bones of the legs. Presentation includes bone pain that worsens over time. Imaging shows an aggressive bone lesion with soft tissue involvement. Biopsy is required for diagnosis. Treatment involves chemotherapy along with surgery or radiation. Prognosis is best when the cancer has not metastasized at diagnosis.

2. EWING SARCOMA
• third most common nonhematologic primary
malignancy of bone,
• second most common (after osteosarcoma) in
patients younger than 30 years of age and the
• most common in patients younger than 10 years
of age.
• The incidence is less than 1 per 1 million per year,
accounting for about 9% of primary malignancies
of bone.
• Most occur in patients 5 to 25 years old.

3. • arise from mesenchymal stem cells in the bone
marrow
• Closely related to other tumours such as primitive
neuroectodermal tumour of soft tissues,
peripheral neuroepithelioma and Askin tumour.
• This highly malignant tumour occurs more
frequently in males, typically between 10 and 20
years of age,
• diaphyseal long-bone location but is equally as
common in flat bones.
• The femur is the most common long-bone site,
followed by the tibia, humerus and fibula, but
overall the pelvis accounts for the majority of
cases.

4. Presentation
• Pain , Usually the onset is insidious, may be of long
duration before the patient seeks medical attention.
• The pain may be only mild and intermittent initially
and may respond to initial conservative treatment.
• The average delay reported to be 34 weeks.
• may have fever, erythema, and swelling, suggesting
osteomyelitis.
• Laboratory studies may reveal an increased WBC , ESR ,
and an CRP level.
• needle aspirate may grossly resemble pus,

5. • Radiographically, an aggressive, permeative,
poorly defined osteolytic lesion with cortical
destruction, periosteal reaction and large, radiolucent
soft-tissue mass may be found.
• Periosteal reaction is common in young patients with
the lamellar ‘onionskin’ appearance causing fusiform
bone enlargement (Figure 9.29).
• This may mimic infection or eosinophilic granuloma in
young patients; subtle bone involvement with a large
soft-tissue mass could mimic primary bone lymphoma
in older patients

6. • Regardless of the location, MRI of the entire bone
should be ordered to evaluate the full extent of
the lesion, which typically extends beyond the
abnormality apparent on plain films.
• MRI is also useful to evaluate the extent of the
soft-tissue mass,
• radiograph and CT of the chest - site of
metastases.
• A bone scan - site of metastases.
• bone marrow aspirate - diffuse systemic disease.

7. • Histologically, Ewing sarcoma consists of small
blue cells with very little intercellular matrix.
• Cytogenetic or immunohistochemical studies
often are required to differentiate Ewing
sarcoma from other small blue cell tumors.
• Ewing sarcomas usually are periodic acid–
Schiff positive (owing to intracellular glycogen)
and reticulin negative.

8. worst prognostic factor
• presence of distant metastases.
• Even with aggressive treatment, patients with metastases have only
a 20% chance of long-term survival.
• Histologic grade is of no prognostic significance because all Ewing
sarcomas are considered high grade.
• Fever, anemia, and elevation of laboratory values (white blood cell
count, erythrocyte sedimentation rate, lactate dehydrogenase) have
been reported to indicate more extensive disease and a worse
prognosis.
• Older age at presentation (with a cutoff around 12 to 15 years old)
and male gender also have been reported to be associated with a
worse prognosis.
• As with osteosarcoma, histologic response to neoadjuvant
chemotherapy has been shown to be prognostically important.
• Greater than 90% necrosis after preoperative chemotherapy
indicates a good prognosis.

9. Treatment
• neoadjuvant or adjuvant chemotherapy, or both,
• Before the use of multiple-agent chemotherapy, long-term
survival was less than 10%.
• Today, most centers report long-term survival rates of 60%
to 75%.
• Local treatment of the primary lesion is more controversial.
• Ewing sarcoma is radiosensitive,
• Increased rate of overall survival with wide resection of the
primary
tumor. T
• large, central, unresectable tumors often are treated with
radiation, whereas smaller, more accessible lesions (which
inherently have a better prognosis) are more likely to be
treated with surgery.

10. • Repeat staging studies should be obtained
after neoadjuvant chemotherapy.
• The repeat radiographs often show increased
ossification, and repeat MRI often shows a
marked decrease in the soft-tissue mass.
• expected function after amputation, limb
salvage surgery, or radiation and the inherent
short-term and long-term risks involved with
each option.

11. • Disease relapse is associated with a poor
prognosis despite aggressive treatment of the
relapse with further surgery, radiation, and
chemotherapy.
• Patients with local recurrence have been
reported to have about a 20% 5-year survival
rate,
• Patients who relapse within the first year after
primary treatment have a worse prognosis than
patients who have an extended disease-free
interval.