Overview
Signs and symptoms
Early signs are typically localized pain and swelling over the affected bone or soft tissue. A palpable mass may develop, and systemic symptoms such as fevers and weight loss are sometimes reported. Tumor growth can weaken bone and lead to a pathologic fracture. Symptoms often progress over weeks to months and may be mistaken for injury or infection.
Characteristics and common sites
On imaging and pathology the tumor shows features distinct from other bone cancers. It most frequently involves the diaphysis (shaft) of long bones and the pelvis, with common locations including:
- Femur (thigh bone)
- Tibia and fibula (lower leg)
- Humerus (upper arm)
- Pelvis and ribs
Diagnosis
Evaluation begins with radiographs and advanced imaging—MRI for local extent, CT or PET for staging. Characteristic radiologic patterns may suggest the diagnosis but a tissue biopsy is required. Under the microscope Ewing's sarcoma is a small, round, blue‑cell tumor; definitive diagnosis often uses molecular tests to detect gene fusions involving EWSR1 and partner genes.
Treatment and prognosis
Management is multimodal. Most patients receive systemic chemotherapy to treat microscopic disease, combined with surgery, radiation therapy, or both to control the primary tumor. The overall outlook depends on factors such as tumor size, location and whether there is metastatic spread at diagnosis. Early detection and coordinated care at specialist centers improve outcomes.
History, epidemiology and notable distinctions
Ewing's sarcoma is rare compared with other childhood cancers and shows a male predominance. It must be distinguished from osteosarcoma, lymphoma, and osteomyelitis, which can present similarly. Advances in imaging, chemotherapy regimens and molecular diagnostics have clarified its biology and improved survival over the past decades, but research continues into targeted and immunologic treatments.