Philadelphia-chromosome-negative chronic myelogenous leukemia with lymphoid stem cell blastic transformation

A patient is described who had blastic transformation of Ph1 negative chronic myelogenous leukemia (Ph1 - CML). Characterization of the leukemic cells revealed a population with a lymphoid stem cell phenotype (cALL-, TdT+, Ia+, cIgM-). This particular phenotype may be responsible for the refractoriness to vincristine and prednisone and the rapid downhill course.