Patients typically seek medical attention due to pain. Common symptoms include localized swelling and pain in the tumor area, intermittent fever, decreased appetite, and weight loss. If the disease affects the lungs, symptoms such as pleural effusion (fluid accumulation around the lungs) and shortness of breath may occur. Involvement of the spinal cord can lead to nerve compression, resulting in numbness, tingling, or weakness. In some cases, Ewing sarcoma is discovered incidentally after a fall or accident, when a bone weakened by the tumor fractures easily. Differential diagnoses include other malignant bone tumors and osteomyelitis (bone infection), which also presents with redness and fever. Approximately 25% of cases show metastasis at the time of diagnosis. Metastatic spread most frequently involves the lungs, bones, and/or bone marrow. Less common sites include the central nervous system and lymph nodes.