No Identifiable Primary, Only Metastases: Case Report of a Small Round Blue Cell Tumor Consistent With Ewing Sarcoma Presenting With Multisystem Spread in a Young Woman

Ewing sarcoma is the second most common malignant bone tumor in children and adolescents but remains rare and highly aggressive. We present the case of a 31-year-old woman with widespread metastatic disease suggestive of Ewing sarcoma, including lung, spinal, and brain involvement at presentation; however, no dominant primary lesion was identified despite extensive imaging. The patient’s clinical course was complicated by neuropathic pain, seizures, and severe treatment-related infections. She was managed with multi-agent chemotherapy and supportive care but ultimately left against medical advice due to socioeconomic constraints. This case illustrates the diagnostic and therapeutic challenges of Ewing sarcoma in low-resource settings and underscores the importance of early detection, molecular confirmation, and multidisciplinary management.