Development of acute myeloblastic leukaemia in a case of aplastic anaemia treated with granulocyte colony-stimulating factor.

We report a case of aplastic anaemia (AA) treated with granulocyte colony-stimulating factor (G-CSF) terminating as acute myeloblastic leukaemia (AML). Because of severe pneumonia, 250 micrograms of G-CSF was administered for 30 d to promote neutrophil recovery. Following G-CSF therapy, myeoblasts appeared, and the diagnosis of AML was then made. The myeloblasts proliferated in response to G-CSF in vitro and in vivo. In AA, development of AML after treatment with G-CSF is rare. Therefore a careful observation for leukaemic transformation is necessary in long-term administration of G-CSF for AA.