Primary Ewing sarcoma of the lung diagnosed on cytology: Case report with review of literature.

: Primary Ewing sarcoma (ES) of the lung is anecdotally rare, with few cases reported in literature. This report describes a 46 year-old man who presented with cough and chest pain. CT Thorax revealed a lesion in the right lung. Ultrasound guided fine-needle aspiration of the mass and subsequent cytologic examination exhibited a small round cell morphology. Immunohistochemistry done on the cell block revealed CD 99 and FLI-1 positivity, confirming the diagnosis of ES. FISH supported the diagnosis, showing the EWSR1 rearrangement. Radiologic investigations ruled out a primary tumour elsewhere, confirming the diagnosis of primary pulmonary ES. The patient was started on chemotherapy.