Normal Cells of the Blood

 

Fig. 1 Early erythropoiesis. a The earliest recognizable red cell precursor is the large dark proerythroblast with loosely arranged nuclear chromatin (1). Below are two orthochromatic erythroblasts (2), on the right a metamyelocyte (3). b Proerythroblast (1). c Proerythroblast (1) next to a myeloblast (2) (see p. 34); lower region of image shows a promyelocyte (3). Toward the upper left are ametamyelocyte (4) and a segmented neutrophilic granulocyte (5).

Fig. 2. The density of the nuclear chromatin is similar in lymphocytes (1) and erythroblasts (2), but in the erythroblast the cytoplasm is wider and similar in color to a polychromatic erythrocyte (3). e Normal red blood cell findings with slight variance in size of the  erythrocytes. A lymphocyte (1) and a few thrombocytes (2) are seen. The erythrocytes are slightly smaller than the nucleus of the lymphocyte nucleus.

 

Fig. 3. Granulocyte precursors. a The least mature precursor in granulopoiesi is themyeloblast, which is released into the blood streamonly under pathologica conditions. A largemyeloblast is shown with a fine reticular nuclear structure and a narrow layer of slightly basophilic cytoplasmwithout granules. bMyeloblast and neutrophilic granulocytes with segmented nuclei (blood smear from a patien with AML). c Myeloblast (1), which shows the start of azurophilic granulation (arrow), and a promyelocyte (2) with copious large azurophilic granules, typically in a perinuclear location. d Large promyelocyte (1), myelocyte (2), metamyelocyte (3), and polychromatic erythroblast (4).

Fig 4. Myelocytes and metamyelocytes. a Early myelocyte. The chromatin structure is denser than that of promyelocytes. The granules do not lie over the nucleus (as can be seen by turning the fine focus adjustment of themicroscope to and fro). The blood smear is froma case of sepsis, hence the intensive granulation. b Slightly activated myelocyte (the cytoplasm is still relatively basophilic). c Typical myelocyte (1) close to a segmented neutrophil (2). d This metamyelocyte is distinguished from a myelocyte by incipient lobe formation.

 

Fig. 5. Neutrophils (neutrophilic granulocytes). a Transitional form between a metamyelocyte and a band cell. b Copious granulation in a band cell (1) (toxic granulation) next to band cells (2) with Döhle bodies (arrows). c Two band cells. d Band cells can also occur as aggregates. e Segmented neutrophilic granulocytes. f Segmented neutrophilic granulocyte after the peroxidase reaction.g Segmented neutrophilic granulocyte after alkaline leukocyte phosphatase (ALP) staining.

 Fig. 6. Variations of segmented neutrophilic granulocytes. a Reactive state wit toxic granulation of the neutrophilic granulocytes, more visibly expressed in the cell on the left (1) than the cell on the right (2) (compare with non activated cells). b Sepsis with toxic granulation, cytoplasmic vacuoles, and Döhle bodie (arrows) in band cells (1) and a monocyte (2). c Pseudo-Pelger cell looking lik sunglasses (toxic or myelodysplastic cause). d Döhle-like basophilic inclusion (arrow) without toxic granulation. Together with giant thrombocytes this suggest May–Hegglin anomaly.

 Fig. 7. continued. e Hypersegmented neutrophilic granulocyte (six or more segments). There is an accumulation of these cells in megaloblastic anemia. f Drumstick (arrow 1) as an appendage with a thin filament bridge to the nucleus (associated with the X-chromosome), adjoined by a thrombocyte (arrow 2). g Very large granulocyte from a blood sample taken after chemotherapy. h Segmented neutrophilic granulocyte during degradation, often seen as an artifact after prolonged sample storage (more than eight hours).

 Fig. 8. Eosinophilic and basophilic granulocytes. a–c Eosinophilic granulocytes with corpuscular, orange-stained granules. d In contrast, the granules of neutrophilic granulocytes are not round butmore bud-shaped. e Basophilic granulocyte. The granules are corpuscular like those of the eosinophilic granulocyte but stain deep blue to violet. f Very prominent large granules in a basophilic granulocyte in chronic myeloproliferative disease.

 

Fig. 9. Monocytes. a–c Range of appearances of typical monocytes with lobed, nucleus, gray–blue stained cytoplasm and fine granulation. d Phagocytic monocyte with plasma vacuoles. e Monocyte (1) to the right of a lymphocyte with azurophilic granules (2). f Monocyte (1) with nucleus resembling that of a band neutrophil, but its cytoplasm stains typically gray–blue. Lymphocyte (2). g A monocyte that has phagocytosed two erythrocytes and harbors them in its wide cytoplasm (arrows) (sample taken after bone marrow transplantation). h Esterase staining, a typical marker enzyme for cells of the monocyte lineage.

Fig. 10.Lymphocytes a–c Range of appearance of normal lymphocytes (some of them adjacent to segmented neutrophilic granulocytes). d In neonates, some lymphocytes froma neonate show irregularly shaped nuclei with notches or hints of segmentation. e A few larger lymphocytes with granulesmay occur in a normal person. f Occasionally, and without any recognizable trigger, the cytoplasm may widen. g A smear taken after infection may contain a few plasma cells, the final, morphologically fully developed cells in the B-lymphocyte series (for further activated lymphocyte forms).

 Fig. 11. Megakaryocytes and thrombocytes. aMegakaryocytes in a bonemarrow smear. The wide cytoplasm displays fine, cloudy granulation as a sign of incipient thrombocyte budding. b Normal density of thrombocytes among the erythrocytes, with little variation in thrombocyte size. c and d Peripheral blood smears with aggregations of thrombocytes. When such aggregates are seen against a background of apparent thrombocytopenia, the phenomenon is called “pseudothrombocytopenia” and is usually an effect of the anticoagulant EDTA.

 

The bone marrow contains a mixture of all the hematopoietic cells

 

Fig. 12. Bonemarrow cytology. a Bonemarrow cytology of normal cell density in a young adult (smear froma bonemarrow spicule shown at the lower right;magnification !100). b More adipocytes with large vacuoles are present in this bone marrow preparation with normal hematopoietic cell densities; usually found in older patients. c Normal bone marrow cytology (magnification !400). Even this overview shows clearly that erythropoiesis (dense, black, round nuclei) accounts for only about one-third of all the cells.

 

Fig. 13 Normal bone marrow findings. a Normal bone marrow: megakaryocyte (1), erythroblasts (2), andmyelocyte (3). b Iron staining in the bonemarrow cytology: iron-storingmacrophage. c Normal bonemarrow with slight preponderance of granulocytopoiesis, e.g., promyelocyte (1), myelocyte (2), metamyelocyte (3), and band granulocyte (4). d Normal bone marrow with slight preponderance of erythropoiesis, e.g., basophilic erythroblast (1), polychromatic erythroblasts (2), and orthochromatic erythroblast (3). Compare (differential diagnosis) with the plasma cell (4) with its eccentric nucleus.

 

Fig. 14. Bone marrow stroma. a Spindle-shaped fibroblasts form the structural framework of the bone marrow (shown here: aplastic hematopoiesis after therapy for multiple myeloma). b A macrophage has phagocytosed residual nuclear material (here after chemotherapy for acute leukemia). c Bone marrow osteoblasts are rarely found in the cytological assessment. The features that distinguish osteoblasts from plasma cells are their more loosely structured nuclei and the cloudy, “busy” basophilic cytoplasm. d Osteoclasts are multinucleated giant cells with wide, spreading cytoplasm.