A case of pelvic Ewing sarcoma misinterpreted as osteomyelitis: diagnostic and clinical implications

Ewing sarcoma of the bone is a highly aggressive malignancy that necessitates immediate chemotherapy upon diagnosis. Its clinical and radiological features often resemble those of osteomyelitis, leading to potential misdiagnosis. Such errors can significantly impact treatment outcomes and prognosis. Misinterpreting Ewing sarcoma as osteomyelitis is uncommon, and documented case reports are rare. This report describes a 24-year-old woman with stage IV Ewing sarcoma of the left pelvis, initially misdiagnosed as osteomyelitis based on imaging findings. The accurate diagnosis was ultimately confirmed through biopsy of a mediastinal metastatic lesion. This case highlights the diagnostic challenges in distinguishing Ewing sarcoma from osteomyelitis and underscores the importance of thorough evaluation, while also summarizing imaging features that may help differentiate the 2 conditions.