Ewing Sarcoma is the third most common primary tumor of bone and the second most common malignant bone tumor of late childhood and early adulthood (1 % of childhood cancers).
Ewing Sarcoma belongs to the small, round, blue-cell tumors that are thought to arise from primitive mesenchymal cells.
EWS gene on chromosome 22
Reciprocal translocation on FL11 gene on chromosome 11t (11,22)
Primitive Neuroectodermal tumor (PNET) of bone tumor
Male: Female::1.4:1
For the First two decades
Site: Most frequent site of involvement
[Pelvis > Long bone > Ribs > Vertebral Column]
Clinical Features
Most common clinical symptoms: Pain and swelling
10 % of patients: Pathological fractures
Tumor is confused with infection
MRI is excellent at describing lesions: Describing in the marrow
X-Ray shows typical Onion Peel appearances
Trisomy-8, CD 99 (+), PAS (+), MIC 2 (+), T (11,22)
Laboratory Investigations
Anemia, Leukocytosis, Increase LDH (Have prognostic significance)
Staging workup: Chest CT
The lungs are the most common site for metastasis
Bone marrow biopsy: Mandatory ( to look for disseminated disease)
Approximately: 25 % of patients present with metastasis
Pathology
Meta diaphysis and diaphysis predominantly
Extensive invasion of medullary bone, destruction of endosteum and cortex
Extend for a greater distance in the medulla (than is apparent n X-rays)
Grayish-white tumors; Encapsulated by fibrous tissues
Microscopic Examinations
Monomorphic cells, small, round, blue cells
Rosette formulation: PNET
Periodic acid Schiff ( PAS is positive)
CD 99 (MIC 2), an immunohistochemistry marker (Positive) for Ewing sarcoma
EWS translocation detection (by PCR or FISH) is mandatory in clinical and pathological presentation is unusual and histological diagnosis is doubtful.
Treatment
Multidisciplinary Actions
Multiagent Chemotherapy
Surgery
Radiation
See also: Musculoskeletal Malignancy: Management
6 cycles of initial chemotherapy
10-12 months duration
In 3 weeks of interval
Myeloablative Therapy and Stem cell transplantation: Uncertain values
Surgery + Radiotherapy are the Principle mode of treatment
Chemotherapeutic Agents
- Doxorubicin
- Cyclophosphamide
- Ifosfamide
- Vincristine
- Etoposide
- Dactinomycin
See also: Osteosarcoma
See also: Limb Salvage Surgery: Principles
