Schematic representation of our current understanding of the pathophysiology of myelodysplasia. In this example, the founding driver mutation is assumed to occur in a hematopoietic cell located in the bone marrow of the right ilium, and the sternum is shown as an anatomically separated bone marrow district to illustrate the concept of mutated stem cell migration through peripheral blood. Bone marrow microphotographs: magnification from 600×, courtesy of Erica Travaglino.