The activity of valproic Acid in the treatment of refractory hyperleukocytosis in a child with acute lymphoblastic leukemia.

Hyperleukocytosis may be associated with an early morbidity and mortality due to leukostasis. Cytoreductive therapies-such as steroids, hydroxiurea, exchange transfusion, and leukapheresis-have been used for the prevention of leukostasis. Herein, the valproic acid used for the treatment of the hyperleukocytosis did not respond to known therapies in a child; lymphoblastic lymphoma developed bone marrow relapse under the treatment is discussed.