Normal Hematopoiesis


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Normal Hematopoiesis

  1. 1. Normal hematopoiesis Cytological and histological aspects
  2. 2. The normal pathways of hematopoiesis
  3. 3. Red cells <ul><li>Normal aspect of red cells (erythrocytes). </li></ul><ul><li>Red cells are anucleated discoid shaped cells, with a diameter of 7-8  . </li></ul><ul><li>They have a central thinner region, viewed microscopically as a lighter central area. </li></ul>
  4. 4. Red cells <ul><li>Reticulocytes are young red cells, just arrived in the peripheral blood from the bone marrow after losing their nucleus. </li></ul><ul><li>They are larger than mature red cells, displaying a reticullum inside the cytoplasm. </li></ul><ul><li>On this slide, there is an excess of reticulocytes, signifying increased regeneration. </li></ul>
  5. 5. Red cell precursors - erythroblasts <ul><li>Erythropietic precursors (erythroblasts) viewed on a bone maroow smear. </li></ul><ul><li>Several forms are observed: the most immature, proerythroblasts (green arrow), then the maturing forms, namely the basophilic (blue arrow), polychromatophil (red arrow) and oxyphil erythroblasts (orange arrow). </li></ul>
  6. 6. Neutrophils and monocytes <ul><li>Neutrophil granulocytes (neutrophils) are the mature cells of the granulocytic lineage, normally appearing on the peripheral smear. </li></ul><ul><li>They are characterized by granular, neutrophilic (neither red , nor blue) cytoplasm and multilobed, segmented nuclei. </li></ul><ul><li>On this image, a monocyte (second from left) is also seen. Monocytes are characterized by hypogranular cytoplasm and an irregular shaped nuclei. </li></ul>
  7. 7. Eosinophils <ul><li>Eosinophilic granulocytes are characterized by a cytoplasm filled with red-orange granules and a nucleus with two or three lobes. </li></ul><ul><li>Increased eosinophilia is characteristic for allergic conditions, parasitic infestations and certain malignancies. </li></ul>
  8. 8. Basophils <ul><li>A neutrophil and a basophil. </li></ul><ul><li>Basophils are characterized by a cytoplasm filled with dark-blue granules and a bilobate nucleus. </li></ul><ul><li>Basophils are rare on the normal peripheral smear (<0.5%). An increased basophil count is characteristic for chronic myeloproliferative diseases, especially chronic myeloid leukemia (CML). </li></ul>
  9. 9. Granulocyte precursors <ul><li>Bone marrow smear showing the maturation stages of the granulocytic lineage: bands (orange arrow), metamyelocytes (red arrow), myelocytes (blue arrow) and promyelocytes (green arrow) are evident on this image. </li></ul><ul><li>Normally, these forms are only found in the bone marrow. In case of increased production such as in sepsis, or in myeloid leukemias, these forms can be also seen on the peripheral blood smear. </li></ul>
  10. 10. Platelets <ul><li>Normal platelets (thrombocytes) are small, 1-3  diameter corpuscles, which are nor really cells, as they have no nuclear material. </li></ul><ul><li>Platelets are actually fragments of megakaryocyte cytoplasm. </li></ul>
  11. 11. Megakaryocytes <ul><li>Megakaryocytes are huge, 20-50 µ diameter cells, with irregular shaped nucelus and abundant, light-eosinophilic cytoplasm, which, by fragmentation gives birth to platelets. </li></ul><ul><li>Megakaryocytes are polyploid cells (possess several sets of chromosomes), as a result of endomytosis. Endomytosis leads to cell growth without division. </li></ul>
  12. 12. Lymphocytes <ul><li>Mature lymphocytes, normally seen on the peripheral smear are small, round cells, with round nucleus and scarce, basophilic cytoplasm. </li></ul><ul><li>Cytologically they are not distinguishable from the neoplastic lymphocytes seen in chronic lymphocytic leukemia. </li></ul>
  13. 13. Plasma cells <ul><li>Plasma cells are easily recognizable, as lymphoid cells with round, off-center placed nucleus and abundant basophilic cytoplasm. </li></ul><ul><li>Normally, plasma cells comprise less than 5% of marrow cellularity. </li></ul>
  14. 14. Bone marrow histology <ul><li>Normal bone marrow histology picture, showing bone trabeculae, adipose cells and the actual marrow (hematopoietic tissue). </li></ul><ul><li>The percentage of fat is variable, amounting to 30-70% of the total surface. </li></ul>
  15. 15. Lymph-node histology <ul><li>A normal, reactive lymph node with benign follicular hyperplasia. </li></ul><ul><li>B-lymphocytes, present in the follicular centers are stained brown, with the anti-CD20 monoclonal antibody. </li></ul>