The Diagnostic Challenge of Therapy-Related Pure Erythroid Leukemia Arising in the Setting of Multiple Myeloma

Abstract

We report two interesting cases of patients with multiple myeloma, who developed a therapy-related myeloid neoplasm in the form of pure erythroid leukemia. In both cases, it was difficult to differentiate the erythroid blasts from plasma blasts by morphology alone. The diagnostic picture was further confounded by the presence of a hyperdiploid karyotype (case 1), which is a frequent cytogenetic abnormality in multiple myeloma but distinctly uncommon in acute myeloid leukemia. These cases highlight the diagnostic challenge encountered with pure erythroid leukemia in the setting of multiple myeloma, and underscore the importance of immunohistochemistry, cytogenetics, and gene rearrangement studies in resolving the diagnostic conundrum. To the best of our knowledge pure erythroid leukemia with a hyperdiploid karyotype arising in a background of pre-existing multiple myeloma, has not previously been reported.