Pulmonary leukostasis without hyperleukocytosis: a clinicopathologic study of 16 cases

Pulmonary leukostasis is a serious, almost always fatal, complication usually reported to occur in patients with acute granulocytic leukemias when the peripheral white blood cells exceed 50,000/mm3. We report a clinicopathologic study of 16 leukemic patients with pulmonary leukostasis and with less than 50,000/mm3 circulating leukocytes. The results demonstrated that hyperleukocytosis per se cannot be the cause of pulmonary leukostasis, but that other factors, such as the presence of circulating blasts and the affinity of neoplastic cells for the pulmonary endothelium, may be related to the development of acute respiratory distress in patients with leukemia.