[Erythroleukemia in multiple myeloma. A case report].

Since the beginning of the seventies there have been an increasing number of reports of second malignancies in patients treated with cytotoxic agents. The commonest of these malignancies are acute nonlymphocytic leukemias. Such occurrences are also known in patients with multiple myeloma treated with melphalan. In a 74-year-old female with multiple myeloma treated with melphalan for 19 months, erythroleukemia developed 23 months after the start of treatment. The second malignancy has almost entirely displaced the myeloma cells in the marrow. In consequence, the paraprotein gradient in electrophoresis diminished in size.