[ACUTE MYELOGENOUS LEUKEMIA, M0, BLOOD]. A myeloblast of an AML-M0 is compared to a medium-sized normal lymphocyte. Note the presence of only very scant cytoplasm in a blast and finer evenly-distributed chromatin in comparison to a lymphocyte. The high nuclear to cytoplasmic ration (N/C ratio) is a common albeit not a required feature of blasts. The single defining morphologic feature of a blast is it’s finely distributed nuclear chromatin.