Adult Myeloproliferative Disorders/Myelodysplastic Syndromes/Overlap Syndromes

Myelodysplastic syndromes and myeloproliferative neoplasms are clonal hematopoietic disorders characterized by distinct clinical features, bone marrow findings and a variable clinical course (with a variable risk of progression to AML). The myelodysplastic syndromes (MDS) are a diverse group of marrow failure syndromes and typically present with cytopenias. These may have a relatively indolent clinical course spanning a few years to one which is rapidly fatal. On the other hand, myeloproliferative neoplasms (MPN) are characterized by clonal proliferation of myeloid precursors in the marrow and extramedullary hematopoiesis. These disorders typically present with normal to elevated blood counts. A small fraction of patients have disorders which have overlapping features of MDS and MPN; these are called overlap syndromes. In this chapter, we discuss the epidemiology, clinical features, approach to diagnosis and risk stratification-based management of these disorders. We also discuss their outcomes with the currently available therapies. Chronic myeloid leukemia (CML) is not discussed here and is discussed in a separate chapter. At the end of the chapter, we summarize the way we manage our patients at our center.