When stained with the usual dyes, the
cytoplasm is distinctly
basophilic and relatively more abundant than in
myeloblasts or
promyelocytes, even though myelocytes are smaller cells. Numerous cytoplasmic
granules are present in the more mature forms of myelocytes. Neutrophilic and eosinophilic granules are
peroxidase-positive, while basophilic granules are not. The nuclear
chromatin is coarser than that observed in a promyelocyte, but it is relatively faintly stained and lacks a well-defined membrane. The nucleus is fairly regular in contour (not indented), and seems to be 'buried' beneath the numerous cytoplasmic granules. (If the nucleus were indented, it would likely be a
metamyelocyte.)
Measurement There is an internationally agreed method of counting blasts, with results from M1 upwards. ==Development==