[5] The megakaryocyte develops through the following lineage: The megakaryoblast is derived from colony forming units (CFU-Meg) of hematopoietic stem cells found in red bone marrow.

[7] Once formed, megakaryoblasts become promegakaryocytes through one or two cycles of endomitosis, which is the division of chromosomes without the cell dividing via cytokinesis.

The promegakaryocytes continue the process of endomitosis, which results in the formation of granular megakaryocytes as the nucleus forms lobes with increased volumes.

[11] Compared to megakaryoblasts, promegakaryocytes and granular megakaryocytes are both larger and contain less basophilic cytoplasm with granules.

Promegakaryocytes are usually about 15μm to 30μm in diameter with a lobed nucleus and some azurophil granules within moderately basophilic cytoplasm.

Granular megakaryocytes are typically 40μm to 60μm in diameter with a large multi-lobed nucleus and an abundance of azurohpil granules within slightly basophilic cytoplasm.