[Plasmocytoma, alkylating agents, and acute myeloid leukemia (author's transl)].

Two cases of the development of acute myeloid leukemia (AML) after treatment with alkylating agents are reported. In Case 1, melphalan and then cyclophosphamide had been given for multiple myeloma. 46 months after onset of cytostatic treatment AML occurred, as confirmed cytochemically and by qualitative determination of urinary lysozyme. In Case 2, cyclophosphamide had been given for rheumatoid arthritis. After a latency of 34 months 'smouldering leukaemia' developed with an atypical monocytic leukaemic cell population. In a third case, multiple myeloma and monocytic leukaemia developed synchronously. The causative role of melphalan and cyclophosphamide in the development of AML seems securely established. Despite the risk of alkylating agents in the treatment of multiple myeloma or Hodgkin's disease causing AML, they should not be replaced, as other drugs have been shown to be less beneficial. On the other hand, alkylating agents should be used with great caution in the treatment of non-malignant diseases.