Ewing's Sarcoma is a rare, highly malignant bone tumor made of small round cells of unknown origin.

Ewing's Sarcoma

pathology slide of ewing's sarcoma, Mass General Orthopaedic Oncology Service

Ewing's Sarcoma pathology

xray of foot without ewing's sarcoma, Mass General Orthopaedic Oncology Service

X-ray showing foot after the Ewing's Sarcoma was removed

Ewing's Sarcoma is a rare, highly malignant bone tumor made of small round cells of unknown origin. It is distinguished from other round cell tumors such as malignant lymphoma of bone, myeloma, neuroblastoma, rhabdomyosarcoma, small cell osteosarcoma and metastatic small cell carcinoma of the lung. Ewing's sarcoma is rare in black populations and usually occurs between the ages of 10-20. Males are affected more frequently than females. Any bone may be involved, but the pelvis and lower extremities are the most common sites. The patient usually presents with pain, swelling, a mass and occasionally fevers, weight loss and fatigue for a few months. Blood tests may reveal anemia (low red blood cell count, low hemoglobin or hematocrit) or show an increase in the sedimentation rate (detects inflammatory, neoplastic/cancer, infectious and necrotic/cell breakdown decay processes). Pathologic fractures may be present. X-rays show a destructive lesion in the bone, a soft tissue mass, and destruction of the cortex which elicits a host response/new bone giving an 'onion skin' look around the tumor. Tumor tissue examined under the microscope shows the closely packed, small round cells.

Treatment for Ewing's sarcoma involves chemotherapy and surgical resection. Radiation therapy has also been used but with caution in young children with growth plate involvement to prevent significant growth deformity. The prognosis (outlook for survival) is now quite good due to advances in chemotherapy. Lung metastases may occur in 20-25% of patients at diagnosis or subsequently and are managed with different chemotherapy, radiation, resection or at times, stem cell transplants.