Megakaryoblast
| Megakaryoblast | |
|---|---|
Haematopoiesis | |
Bone marrow smears of acute megakaryoblastic leukemia, with May-Grün-wald-Giemsa staining, ×100. (A) Cytoplasmic blebs (black arrow) and binucleated cell. (B) Cell cluster giving a pseudo-solid tumor aspect of AMKL. | |
| Identifiers | |
| TH | H2.00.04.3.05002 |
| FMA | 84235 |
| Anatomical terms of microanatomy | |
A megakaryoblast (from mega- 'large' karyo- 'cell nucleus' and -blast 'precursor cell') is a precursor cell to a promegakaryocyte. During thrombopoiesis, the promegakaryocyte matures into the form of a megakaryocyte. From the megakaryocyte, platelets are formed. The megakaryoblast is the beginning of the thrombocytic series or platelet forming series.
Megakaryoblasts typically have a large oval-shaped nucleus or a nucleus that is lobed with many nuclei. The megakaryoblast resembles the myeloblast or lymphoblast morphologically; however the megakaryoblast varies in phenotype and the structure viewed with electron microscopy.
Increased amounts of megakaryoblasts in the bone marrow may indicate a disease state. An example of this is acute megakaryoblastic leukemia, which occurs when the level of megakaryoblasts in the bone marrow exceeds 20%.