Leukostasis caused by hyperleukocytosis secondary to childhood leukemia

Abstract

Leukostasis is a severe complication of hyperleukocytosis secondary to childhood leukemia. Although increased leukocyte counts tend to induce the occurrence of leukostasis, additional factors may be involved in the pathogenesis of leukostasis, such as the size and deformability of blast cells, and the expression levels of adhesion molecules. Such factors might explain why the incidence of leukostasis differs among acute myeloid leukemia, acute lymphoblastic leukemia, and chronic myeloid leukemia. Leukostasis is associated with an increased risk of early death, and is considered to involve blast cell aggregates and thrombi in the circulation, inducing tissue hypoxia. The central nervous system and lungs are the most common sites for leukostasis. Although the pathological definition of leukostasis is clear, its clinical diagnosis is rarely made with high confidence. Because leukostasis is an oncological emergency, leukapheresis may prove beneficial in cases manifesting severe leukostatic symptoms, and immediate initiation of chemotherapy for this chemosensitive disease should not be delayed.