Dysplastic changes in smears from NPM1-mutated AML. (A) Dysgranulopoiesis (DysG) in a case of NPM1-mutated AML showing myeloid cells with hypogranulated cytoplasm and pseudo-Pelger cells. Bone marrow; Pappenheim staining. (B) Dyserythropoiesis (DysE) in a case of NPM1-mutated AML showing nuclear irregularity with fragmentation and multinucleation of red precursors. Bone marrow; Pappenheim staining. (C) Dysmegakaryopoiesis (DysM) in a case of NPM1-mutated AML showing 2 dysplastic megakaryocytes with multiple nuclei; Pappenheim staining. All images were collected using a Zeiss Axio Imager A1, 63×/1.4 oil objective Plan-Apochromat; 10×/23 eyepiece Sony camera 3CCD HD, and Model MC-HD 1/3 Horn imaging DHS solution. (D) LightCycler-based melting curve analyses showing different NPM1 mutation types in AML with MLD changes: type A (nt959insTCTG), type D (nt959insCCTG), type I (nt959insCTTG), type X (nt959insTTCC), and wild-type patients. (E-F) Expression of CD34 by multiparameter flow cytometry. A case with NPM1 mutation and MLD changes shows a lack of expression of CD34 (panel E, note the different levels of CD33 expression between myeloblasts and monoblasts). A different AML MLD⁺ case without NPM1 mutation shows a strong expression of CD34 with a part of the population lacking CD33 expression (F).