[The significance of myelodysplasia in untreated patients with multiple myeloma].

Microscopic analysis of bone marrow smears from ten untreated patients with multiple myeloma (MM) revealed that seven patients had myelodysplastic changes. Of these, five patients had anemia alone while the other two had anemia and leucopenia. The myelodysplastic changes seen in MM were less extensive than those seen in myelodysplastic syndrome (MDS). Moreover, the dysplastic changes in MM were determined to be limited to two or three lineage cells. Dysplastic changes were observed even after clinical signs of MM had improved due to therapy. We consider that the myelodysplastic changes seen in MM can be attributed to MM itself, rather than to the coexistence of MDS and MM. Such findings suggest that the pathogenesis of MM involves a common stem cell which differentiates into multiple lineage cells.