CRA87 EXTRAOSSEOUS EWING SARCOMA PRESENTING AS MEDIASTINAL MASS IN AN ADULT: A DIAGNOSTIC CHALLENGE

MR Sulaiman^1,3, WA Wan Ahmed^{1, 3} and WFWA Rahman^{2, 3}.

¹Department of Radiology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
²Department of Pathology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
³Hospital Pakar Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.

Ewing sarcoma (ES) is a malignant bone tumour that typically seen in children and adolescents. While the primary lesions commonly arise in the long bones and pelvis, extraosseous presentations, particularly in the mediastinum are extremely rare, especially in adults. We present the case of a 52-year-old male who presented with progressive dyspnoea and cough. Contrast-enhanced computed tomography (CECT) of the thorax demonstrated a large, heterogeneous, lobulated, soft tissue mass in the mediastinum, without evidence of primary bone lesion. A CT-guided core needle biopsy was performed, and histopathology confirmed the diagnosis of mediastinal Ewing sarcoma. This case emphasizes the diagnostic challenge of mediastinal Ewing sarcoma in adults, which can mimic more common mediastinal tumours on imaging. It reinforces the importance of including rare entities in differential diagnosis and the necessity of early histopathological analysis for accurate diagnosis. Early recognition and management of highly aggressive tumour are essential for better prognosis, even more so in critical regions such as mediastinum.

Keywords: Ewing sarcoma, primary mediastinal Ewing sarcoma, mediastinal mass, extraosseous Ewing sarcoma.