Chromosomal abnormalities and dyserythropoiesis in the preleukaemic phase of multiple myeloma.

Two patients with multiple myeloma and one patient with a plasma-cytoma are reported in whom acute leukaemia developed following long-term treatment with melphalan. Each patient had a complete remission of the plasma cell disorder during which time the bone marrow was moderately to severely hypoplastic. The end of the clinical remission was heralded by a dyserythropoietic anaemia which persisted several months before the emergence of the terminal acute leukaemia. Marked chromosomal abnormalities were observed in marrow cells during the dyserythropoietic phase.