Ewing's sarcoma accounts for approximately 10% of malignant bone tumors. The male: female ratio is 3:2. Clinically presents as pain with swelling and a palpable mass. Back pain and parathesias can be associated with paraspinal or pelvic tumors. Common nonspecific systemic manifestations include fever, fatigue, weight loss, and anemia mimicking acute or chronic infection. Additional symptoms and signs depend on the specific location of the tumor. Ewing's sarcoma can affect all bones, but is slightly more common in tubular bones. The flat bones most often involved are the ilium, ischium, rib, and scapula. More than 50% of patients have a soft tissue component. Ewing's sarcoma is one of the few bone sarcomas that affect the bones of the hands and feet, although in less than 5% of patients. Hematogenous dissemination is frequent to the lung, bones, and bone marrow. Extraosseous extension is common. On plain radiographs classic appearance is an intramedullary lesion with aggressive permeative or moth-eaten bone destruction. Periosteal new bone can be laminated or interrupted with a "sunburst" appearance. A Codman's triangle is less commonly seen. A characteristic, but not specific, appearance is subperiosteal extension with subperiosteal bone destruction producing a concave "saucerization" defect.
After going through literature on ES of ilium and surfing through pubmed data base, no case of ES of the ilium mimicking inflammatory arthritis hip has been reported to the best of our knowledge. Although ES ilium mimicking sacroiliitis have been reported [7, 8]. The radiologic appearance of inflammatory and tumorous lesions in the iliac bone is characterized by destructive alterations and consolidations simultaneously. This pattern is nonspecific. The value of plain films of this area is compromised by the anatomy of the iliac bone and by overlying structures. Therefore MRI, computer tomography and bone scans are necessary [10]. CT is helpful in defining the tumor of ES by showing the pattern of bone destruction and the associated soft-tissue mass. MRI is more sensitive than CT in showing soft-tissue involvement and bone marrow metastases. Definitive diagnosis is by an open biopsy and histological examination combined with immunochemistry and cytogenetics.
Before starting treatment patients should be evaluated by specialists from all disciplines (e.g., radiologist, chemotherapist, pathologist, surgeon or orthopedic oncologist, and radiation oncologist) as early as possible. The surgeon or orthopedic oncologist who will perform the definitive surgery should be involved prior to or during the biopsy so that the incision can be placed in an acceptable location. The successful treatment of patients with Ewing family of tumors (EFT) requires systemic chemotherapy in conjunction with either surgery or radiation therapy or both modalities for local tumor control. In general, patients receive preoperative chemotherapy prior to instituting local control measures. Multidrug chemotherapy for EFT always includes vincristine, doxorubicin, ifosfamide, and etoposide. Most protocols use cyclophosphamide as well. We did not use cyclophosphamide in our patient. Duration of primary chemotherapy ranges from 6 months to approximately 1 year. While surgery is effective and appropriate for patients who can undergo complete resection with acceptable morbidity, children who have unresectable tumors or who would suffer loss of function are treated with radiation therapy alone. Those who undergo gross resections with microscopic residual disease may benefit from adjuvant radiation therapy. Prognosis depends on extent of the disease, size and location of the tumor, presence or absence of the tumor metastasis, tumor response to therapy, age,and disease relapse. Most centers today report long term survival of 60% to 70%. The worst prognostic factor is the presence of distant metastasis. Even with aggressive treatment, patients with metastasis have only a chance of 20% long term survival. Histological grades are of no prognostic significance. As already mentioned fever, anemia and elevation of WBC, ESR and lactate dehydrogenase have been reported to indicate more extensive disease and a worse prognosis.