Pulmonary Ewing Sarcoma Mimicking Small Cell Lung Cancer

• Ewing sarcoma, also known as peripheral neuroectodermal tumor, may closely resemble small cell lung cancer (SCLC) in its morphology and immunohistochemistry profile. • Ewing sarcoma typically affects pelvis and long bones; however, Ewing sarcoma of chest wall, known as Askin-Rosai tumor, and pulmonary Ewing sarcoma have been described in literature. • We reported a lifelong non-smoking patient with pulmonary Ewing sarcoma, initially misdiagnosed as SCLC. • -Subsequently, next generation sequencing (NGS) revealed a rearrangement in EWSR1, establishing the correct diagnosis. • -When SCLC is diagnosed in non-smokers, NGS can be useful to rule out the possibility of Ewing sarcoma. © 2022 Elsevier Inc.