The nomenclature and classification of myeloid malignancies and our understanding of how these disorders are and are not related to each other continue to evolve. As discussed in Chapter 10, the diagnosis of acute myeloid leukemia (AML) is relatively straightforward and is based largely on the percentage of blasts in the bone marrow and on their morphologic, immunohistochemical, and immunophenotypic features. Similarly, the myeloproliferative diseases (MPDs), discussed in Chapter 8, are characterized by the clonal expansion of malignant hematopoietic stem cells that retain the capacity to differentiate into mature blood cells. The association of recurring cytogenetic abnormalities with specific disease . . . [Full Text of this Article]