Refractory anaemia with hypereosinophilia and clonal abnormal metaphases detected only in the neutrophilic granulopoietic series.

We report a case with refractory anaemia terminating in an acute leukaemia, which showed from the very beginning an intense eosinophilia that lasted for the whole disease, and in which the eosinophilic metaphases, as documented by the 'Morphology, Antibody, Chromosome' technique, were normal. An unusual karyotypic anomaly in the setting of a myelodysplastic syndrome could only be detected in the neutrophilic series. A general approach to detect structural aberrations of specific human chromosomes in metaphase cells by chromosomal in situ suppression hybridization of DNA libraries from sorted human chromosomes has been applied for chromosomes 11, 3 and 2, in order to identify an extra copy of chromosome 2.