Second most common primary bone tumor in children and adolescents, after osteosarcoma
Etiology
Pathophysiology
Clinical features
Localization
Primary tumor: often diaphyses of long bones (particularly femur, tibia, fibula, and humerus) and bones of the pelvis
Metastasis: lungs, skeletal system, bone marrow
Frequently first manifests with localized pain (progressive, worsens at night), hyperthermia, and swelling after trauma to the bone (tissue mass that is tender to palpation and accompanied by erythema)
B symptoms are common.
Diagnostics
Conventional X-ray
Lytic bone lesions
Onion skin appearance of the periosteum
Biopsy
Anaplastic small-blue-round-cell malignancy
Tumor cells resemble lymphocytes.
Differential diagnoses include lymphoma and chronic osteomyelitis.
Chromosomal translocation t(11;22)(q24;q12) which leads to expression of fusion protein EWS-FLI1
