No major differences in outcomes between the initial and relapse episodes in patients with thrombotic thrombocytopenic purpura: The experience from the Ohio State University Registry

Pure erythroid leukemiaTo the Editor: Mea culpa.Wang et al. 1 are quite right to point out that in the 2016 WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues pure erythroid leukemia that evolves from a myelodysplastic syndrome (MDS) is not recognized as acute myeloid leukemia (AML) with myelodysplasia-related changes, because it does not meet the criterion of having at least 20% peripheral blood or bone marrow blasts.Since this condition is recognized as AML and evolves from MDS, this is somewhat puzzling.Perhaps how it is best categorized should be reconsidered in the next revision of the WHO classification.The valuable data of Wang et al. 1,2 will help to better define the nature of this rare condition.Meanwhile, it does seem that cases that are therapy related are indeed classified as therapy-related myeloid neoplasm rather than as pure erythroid leukemia.