Filgrastim induced thrombocytopenia.

Drug-induced thrombocytopenia (DITP) is suggested by severe thrombocytopenia with subsequent recovery of platelet count after removal of the offending drug. The diagnosis is ascertained when there is reproducibility of thrombocytopenia with repeated exposure. Filgrastim is used during peripheral blood progenitor cell harvest during autologous stem cell transplantation in the setting of multiple myeloma to prolong event-free survival and overall mortality. The following case illustrates all of the suggestive features of DITP after filgrastim exposure during elective stem cell harvest. Due to the inability to tolerate filgrastim, autologous stem cell transplant was aborted in this patient and he was maintained on induction chemotherapy.