The morphology of dyserythropoiesis in a patient with acute erythroleukaemia associated with multiple myeloma.

A patient with multiple myeloma in whom acute erythroleukaemia developed 5 years following treatment with irradiation and melphalan is reported. Immunoglobulin synthesis and immunofluorescence investigations provided evidence that the blast cells in the peripheral blood did not belong to the plasma cell series; ultrastructure examination demonstrated their myeloid origin. Chromosomally abnormal cells were observed in both the bone marrow and peripheral blood. Light-and electron microscopy of erythropoiesis in this case showed distinct features of dyserythropoiesis, similar to those described in other entities. The erythroid cell abnormalities are discussed in the light of their being either indications of malignancy or of a reactive process.