When the unexpected strikes the pleura: A case of Ewing Sarcoma

Pleural Ewing Sarcoma

Abstract

ABSTRACT

Background: Ewing sarcoma (ES) is a highly aggressive malignant small round blue cell tumor that primarily affects the bones of children and young adults, while its extraosseous form, known as extraskeletal Ewing sarcoma (EES), arises from soft tissues without bone involvement and is exceedingly rare. Primary pleural EES is an exceptional presentation that often mimics other pleural diseases, leading to diagnostic challenges.
Case Presentation: We report the case of a 23-year-old female athlete who presented with persistent left-sided chest pain and dyspnea following chest trauma. Contrast-enhanced CT of the chest revealed a pleural-based soft tissue mass, which was surgically excised. Histopathological examination showed sheets of uniform small round blue cells with diffuse membranous CD99 positivity and nuclear FLI-1 and NKX2.2 expression, confirming the diagnosis of Ewing sarcoma. Postoperative PET/CT demonstrated faint FDG uptake at the excision site, likely representing postoperative changes, and the patient remains under close follow-up.
Conclusion: This case highlights the rarity of primary pleural EES and emphasizes the importance of considering it in the differential diagnosis of pleural-based lesions in young adults. Early recognition through a multidisciplinary approach integrating imaging, histopathology, immunohistochemistry, and molecular testing is crucial for accurate diagnosis and optimal management.