Myelodysplastic/myeloproliferative disorders

Although myelodysplastic syndromes and myeloproliferative disorders appear to have entirely different pathophysiological mechanisms, the existence of conditions with overlapping features is well established. The World Health Organization (WHO) classification of the myeloid neoplasms introduced the category of myelodysplastic/myeloproliferative diseases, which includes myeloid disorders that have both dysplastic and proliferative features at the time of initial presentation and that are difficult to assign to either the myelodysplastic or myeloproliferative group of diseases. The following disorders belong to this category: chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia, juvenile myelomonocytic leukemia, and myelodysplastic/myeloproliferative disease, unclassifiable (MDS/MPD, U).