Extramedullary hematopoiesis is rarely found in the gastrointestinal tract. A patient with postpolycythemic myeloid metaplasia who previously underwent splenectomy presented with recurrent, protracted gastrointestinal tract hemorrhage. Elaborate workup failed to reveal the source of bleeding. Intraoperative endoscopy with transillumination disclosed multiple submucosal lesions along the entire small bowel, which proved to be extramedullary hematopoiesis. After institution of hydroxyurea therapy, the rate of bleeding diminished considerably.
Schreibman D, Brenner B, Jacobs R, Ben-Arieh Y, Tatarsky I, Alroy G. Small Intestinal Myeloid Metaplasia. JAMA. 1988;259(17):2580-2582. doi:10.1001/jama.1988.03720170056034