Myeloblast and promyelocyte in bone marrow smear (human)

Stain: May-Grnwald-Giemsa (MGG). The myeoloblast (1) measures 12-20 m and has a high nucleus-cytoplasm ratio and a round to oval nucleus. The nucleus has a fine disperse diffuse chromatin and one to five prominent nucleoli. The cytoplasm is pale blue (basophilic) with no or only scarce numbers of azurophilic granules. The promyelocyte (2) is larger than the myeloblast (15-25 m), has a lower nucleo-cytoplasmic ratio and the cytoplasm is usually more basophilic but contains also many primary or azurophilic granules arranged around the pale Golgi area. Chromatin is more condensed than in the myoblast. Cellular maturation is associated with progressive chromatin condensation. (3) a neutrophilic granulocyte with a banded nucleus, a more condensed chromatin, and very fine dust-like granules (sometimes hardly visible).