Extramedullar central nervous system blast crisis – rare occurrence in chronic myeloid leukemia

Abstract

Chronic myelogenous leukemia (CML) is a myelo­pro­li­fe­rative neoplasm characterized by the presence of the Philadelphia chromosome. CML is classified into chronic, accelerated and blast phases. The blast crisis is characterized by the rapid expansion of a population of myeloid or lymphoid differentiation-arrested blast cells. Extramedullary blast crisis is defined as blast infiltration in other sites regardless of bone marrow blast proliferation. We report the case of a 59-year-old woman diagnosed with blast phase CML. Initially, the patient had an optimal response to tyrosine kinase inhibitors, but later she developed central nervous system blast crisis.