Relapse of aggressive myeloma after complete remission in secondary acute leukemia: coincidence or consequence?

We describe a patient with multiple myeloma who developed secondary acute myelomonocytic leukemia after long-term melphalan treatment. Following two courses of low-dose cytarabine, complete remission of the A.M.L. was achieved. Shortly thereafter an aggressive relapse of the quiescent myeloma occurred with acute renal failure and massive infiltration of bone marrow with multinucleated giant plasma cells. Although it is well known that administration of melphalan to patients with multiple myeloma increases the likelihood of A.M.L., this case demonstrates that treatment of A.M.L. in a patient with multiple myeloma may perhaps influence the course of multiple myeloma.