Abstract
BACKGROUND: Ewing sarcoma rarely arises in the gastrointestinal (GI) tract, and rectosigmoid presentations are exceptionally uncommon. CASE PRESENTATION: 36-year-old man with rectosigmoid mass showing small round blue cells with pseudorosettes, CD99 and FLI1 positive, diagnosed as Ewing sarcoma; managed with surgical resection followed by chemotherapy. CONCLUSION: Primary EES of rectosigmoid is extremely rare; diagnosis requires morphology, IHC and molecular testing wherever possible; early biopsy allows neoadjuvant chemo before surgery.