Myeloproliferative disorders are a group of diseases where the bone marrow produces too many blood cells. Histologically, these disorders often show hypercellularity of the bone marrow with an increase in one or more types of blood cells. For instance, in polycythemia vera, there is an overproduction of red blood cells, whereas in chronic myeloid leukemia (CML), there is an excess of granulocytes.
