Simultaneous occurrence of tetrasomy 21 and trisomy 8 in a patient with early blastic metamorphosis of chronic myeloproliferative disorder

Abstract
We report an unusual hyperdiploid karyotype characterized by the simultaneous occurrence of tetrasomy 21 and trisomy 8 detected during early blastic evolution of a BCR‐ABL‐negative chronic myeloproliferative disorder. Blast cells from this patient showed a striking response to all‐trans‐retinoic acid (ATRA)‐induced differentiation as evaluated by CD15 expression following in vitro exposure to this inducer. Our report represents the first description of such a composite karyotype in human hematologic malignancies.