Lymphoid blast crisis at the onset of chronic myelogenous leukaemia: molecular evidence

A patient with a typical haematological pattern of acute lymphoblastic leukaemia with BCR and IgH rearrangements was brought into complete remission by treatment. A few weeks later she developed the typical peripheral and bone marrow pattern of chronic myelogenous leukaemia (CML) with persistence of the BCR rearrangement and disappearance of the IgH rearrangement, suggesting that this case is an example of CML presenting in blast crisis without a detectable chronic phase.