Massive Pulmonary Ewing Sarcoma Mimicking Pulmonary Embolism: A Diagnostic Challenge

While classic Ewing sarcoma targets bone, the extra-skeletal variant develops in soft tissues, with a rare incidence of 0.4 per million. Although the chest wall is a recognized site for extra-skeletal Ewing sarcoma, primary pulmonary Ewing sarcoma is exceptionally rare, representing less than 1% of all extra-skeletal Ewing sarcoma cases. An 18-year-old female experienced dyspnea, tachycardia, and cough for 5 months. After not responding to symptomatic therapy, she presented to the emergency department for acute worsening of dyspnea and tachycardia, raising clinical suspicion for pulmonary embolism. Computed tomography revealed a massive pulmonary mass and a pleural effusion. Immunostaining findings were consistent with Ewing sarcoma. She was treated with chemotherapy as per protocol VDC/IE (Vincristine, Doxorubicin, Cyclophosphamide/Ifosfamide, Etoposide). She responded well to therapy, with a marked reduction in tumor size. Pulmonary Ewing sarcoma remains a rare and diagnostically challenging condition requiring a high index of suspicion and multidisciplinary management. This case highlights the need for further research to optimize diagnostic and therapeutic strategies.