Chronic myelomonocytic leukemia as a transformation from polycythemia vera

Abstract The hallmark of Polycythemia vera (PV) is the presence of JAK2 V617F mutation and increased RBC mass. Chronic myelomonocytic leukemia (CMML) is defined as persistent blood absolute monocyte count (AMC) >/= 1 × 10 9 /L for at least 3 months with myeloid cell dysplasia. Few cases of evolved CMML from PV have been described. We present a case of PV that progressed to CMML. We demonstrated the CMML clone was most likely derived from PV- JAK2 V617F clone. This clone carried a complex genetic mutations of ASXL1, RUNX1, SRSF2 and TET2, NRAS, KRAS , plus CMML cells were of the classical phenotype CD14 + CD16 − by flow cytometry.