A Case of Ewing’s Sarcoma of the Mediastinum in a 63‐Year‐Old Woman Initially Misdiagnosed as Non‐Small‐Cell Lung Cancer Successfully Treated With Chemotherapy and Radiation With a Durable Response

Mediastinal Ewing’s sarcoma is an exceptionally rare malignancy, with an incidence of approximately 0.3%. Due to the rarity of the tumor and challenges such as limited tissue availability, diagnosis can be difficult. Curative treatment typically requires a multimodal approach, including intensive chemotherapy, surgery, and radiation therapy. In cases of unresectable or metastatic disease, the prognosis is poor, and treatment generally involves chemotherapy, with or without radiation. We present the case of a 63‐year‐old woman with multiple comorbidities who was initially misdiagnosed with non‐small‐cell lung cancer. Using molecular studies, the correct diagnosis of Ewing’s sarcoma was established. She underwent concurrent chemoradiation therapy followed by maintenance chemotherapy, resulting in an excellent response. She has maintained this response and has been off therapy for nearly 24 months.