Tumefactive extramedullary hematopoiesis of the stomach.

A 3 X 4 cm submucosal gastric mass of extramedullary hematopoeitic tissue occurred in a patient with chronic myelogenous leukemia. Such stomach masses have been misinterpreted as malignant tumor. Tumefactive extramedullary hematopoiesis of the stomach is an infrequent occurrence in patients with extramedullary hematopoiesis but should be considered in the differential diagnosis of patients known to have this condition.