Recurrent spleen enlargement during cyclic granulocyte-macrophage colony-stimulating factor therapy for myelodysplastic syndrome.

A 65-year-old woman with refractory anemia with excess of blasts received sequential courses of granulocyte-macrophage colony-stimulating factor therapy (GM-CSF) and low-dose cytosine arabinoside. Each course of GM-CSF induced a rapid and tremendous increase in leukocyte count as well as in spleen size, 111indium chloride scanning suggested a myeloid metaplasia of the spleen. This observation suggests that in some patients the granulopoietic response to the myeloid growth factor stimulation may be predominant in the spleen.