Differentiation of Extramedullary Acute Promyelocytic Leukemia by All-Trans-Retinoic Acid

Abstract
The effect of all-trans-retinoic acid (ATRA) on extramedullary acute promyelocytic leukemia (APL) has not been fully delineated. We report an unusual case of APL in which a patient relapsed in the skin and central nervous system. Cytodifferentiation of leukemic cells from these extramedullary sites was demonstrated following treatment with ATRA.