A 21-year-old man with anemia and gastrointestinal bleeding caused by jejunal EBV-associated T/natural killer-cell lymphoproliferative disorder.

We report a 21-year-old man who developed abdominal pain, bleeding, and anemia caused by a rare Epstein-Barr virus-related T/NK-cell lymphoproliferative disorder in the small intestine. Initial endoscopy detected ulcers in the duodenum and jejunum, but the cause was unclear from the clinical and imaging findings alone. Biopsy later showed abnormal lymphoid cell growth, and further testing, including immunohistochemistry and EBER staining, confirmed EBV-associated disease limited to the gastrointestinal tract. The patient began combination chemotherapy and remains under follow-up. This case highlights that such EBV-positive lymphoid disorders can be easily overlooked because their symptoms and endoscopic features are nonspecific. Careful tissue evaluation and timely treatment are crucial due to their aggressive behavior and uncertain prognosis.