Pulmonary Ewing Sarcoma Presenting As Chronic Cough.

Ewing sarcoma is an aggressive malignant small round cell tumour primarily affecting bone and soft tissue in young individuals. Pulmonary involvement is commonly seen in metastatic disease, while late recurrence after a prolonged disease-free interval is uncommon and may pose a diagnostic challenge. We report a 26-year-old male with previously treated non-metastatic Ewing sarcoma of the left fibula, who presented four years later with persistent chronic cough. Imaging revealed a large heterogeneously enhancing mass in the left lower lobe with bronchial cutoff, raising suspicion for primary lung malignancy. However, histopathology demonstrated small round blue cells, and immunohistochemistry confirmed Ewing sarcoma, consistent with late primary recurrence. This case underscores the importance of maintaining a high index of suspicion for recurrence in patients with prior malignancy presenting with non-specific respiratory symptoms. It highlights the potential for atypical presentations and the need for timely imaging and tissue diagnosis to guide appropriate management.