Pentasomy 13q in a case of acute myelogenous leukemia (Mo)

A case of acute myelogenous leukemia Mo FAB subtype with a pentasomy 13q (associated with a trisomy 19 in a subclone) in the initial bone marrow metaphase cells is reported. The pentasomy 13q is the result of the presence of double isochromosome 13q and one normal chromosome 13. In our case, this abnormality had a poor prognosis.