A 75 year-old woman presented with fevers, night sweats and weight loss four months after completing a course of adjuvant chemotherapy for ovarian cancer. A CBC showed normocytic anemia (hemoglobin 56 g/L), thrombocytopenia (34 × 109/L) and leukocytosis (16.6 × 109/L) with a granulocyte left-shift and 11% blasts. The peripheral blood findings seen in this patient illustrate the different manifestations of myelodysplasia in the granulocytes: cells with ring nuclei (Figure 1, panels A and B), christened “donut cells”; cells with abnormal cytoplasmic granules (pseudo Chediak-Higashi granules; panel C), and bi-lobed nuclei (pseudo Pelger-Huet cells; panel D and panel E, arrow). Platelets were large and agranular (panel D, arrow) which are also part of the underlying dysplasia. Nucleated RBCs were also present in the peripheral blood suggesting trilineage dysplasia (panel F).
The bone marrow was hypercellular with trilineage dysplasia and 22% myeloblasts with a complex karyotype (including del-5q and del-7).  She was treated with four cycles of decitabine, resulting in resolution of fevers, eradication of bone marrow blasts, and restoration of normal hematopoiesis. Evidence for a salutary effect of the hypomethylating agent in this patient was seen also by restoration of normal peripheral blood cells morphology (panels G–I).
This case illustrates several unique morphological changes in dysplastic granulocytes on a peripheral blood smear in one patient with secondary acute myeloid leukemia.