Massive extramedullary disease progression in a patient with stable multiple myeloma during G-CSF priming for peripheral blood progenitor mobilization

High dose therapy followed by autologous peripheral blood progenitor cell ( PBPC) transplantation has recently become an encouraging treatment option f or younger patients with multiple myeloma (MM). The influence of the growth factors used for progenitor mobilization on myeloma cells is not known. We report on a patient suffering from IgG kappa myeloma who had been in stabl e, very good partial remission for seven months after standard therapy unti l PBPC mobilization with granulocyte-colony stimulating factor (G-CSF, Filg rastim) was initiated. Massive extramedullary disease progression occured c oincidentally with the administration of G-CSF. The case suggest the possib ility of myeloma stimulation by G-CSF during PBPC mobilization.