Figure 1.

Clinical cases: hematologic changes in 3 patients with dysplastic, macrocytic anemia. (A–E) Hematologic parameters of Case 1 are shown. Blue arrow: palbociclib start; red arrow: last date of palbociclib treatment. (A) Hemoglobin decreases with palbociclib use. (B) Mean corpuscular volume (MCV) increases with palbociclib (plateau after 4–5 cycles and correlates with lower hemoglobin level), and returns to baseline 4 cycles after palbociclib discontinuation. (C) Red cell distribution width (RDW) initially increases but returns to normal after 4 cycles of palbociclib initiation, and increases upon palbociclib discontinuation. (D) Absolute neutrophil count with slight decrease over time with palbociclib use. (E) Platelet count shows normal values during palbociclib treatment. (F–M) Peripheral smears and bone marrow aspirates from our 3 index cases (Case 1, Case 2, and Case 3). (F) Granulocytes with karyorrhexis 100X, (G) giant band 100X, (H) bilobed neutrophil with hypogranular cytoplasm, Wright-Geimsa 100X, (I) nucleated red cell and dysplastic neutrophil, Wright-Geimsa 100X, (J) dysplastic hypogranular neutrophils, Wright-Geimsa100X, and (K) macrocytic red blood cells and dysplastic neutrophils, Wright-Geimsa100X. (L) Bone marrow aspirate with binucleated red cell and nuclear irregularity in erythroid precursors, Wright stain 100X. (M) Beginning of erythroid nuclear fragmentation, Wright stain 100X.