Band and segmented neutrophil. Marrow film. The band neutrophil has the same cytoplasmic appearance as its predecessor, the neutrophilic metamyelocyte, that is a tan coloration throughout the cytoplasm, reflecting the neutral staining properties of the neutrophilic granules, not individually discernible because they are less than 0.5 μm in diameter. The sole distinguishing feature of this state of maturation is the sausage shaped nucleus with a thickness that is nearly identical from one end of the nucleus to the other with no hint of segmentation. A segmented neutrophil sits adjacent to the band neutrophil. Note the clear segmentation with one lobe being connected to the remainder of the nucleus by a very thin strand. Note irregularities in the main body of the nucleus with minor and major constrictions and another developing segment apparent at the right end of the nucleus. The nuclear chromatin is more condensed and darker than that of the band neutrophil. A small lymphocyte is at the bottom of the field. In supravital preparations nuclear segmentation is a dynamic event with changing lobe numbers and areas of segmentation.
Basophilic myelocyte. Marrow film. Composite of four basophilic myelocytes at different stages of maturation. Each has a high nuclear to cytoplasm ratio. Each has as yet only scant basophilic granulation.
Eosinophilic metamyelocytes. (A and B). Marrow film. Two eosinophilic metamyelocytes. Note reniform nucleus. Neutrophilic myelocyte in (B). Note marked distinction of cytoplasmic coloration of eosinophil (orange-red) compared to neutrophil (tan). (C) Segmented eosinophil. The transition from metamyelocyte to segmented eosinophil is rapid, making identification of band forms infrequent in normal marrow. Normal eosinophils rarely have more than two nuclear segments.
Eosinophilic myelocyte. Marrow film. The field contains two cells: an eosinophilic (left) and a neutrophilic (right) myelocyte. This eosinophilic myelocyte has a circular, non-segmented nucleus and a nearly full complement of cytoplasmic eosinophilic granules.
Eosinophilic myelocytes, early. Marrow film. (A–C). Three early myelocytes with cytoplasm partially filled with eosinophilic granules. Note also the relatively immature nuclei with little condensation of chromatin, especially in (A) and (B). This is the earliest stage of marrow eosinophilopoiesis identifiable by light microscopy. A band neutrophil is also present in (C).