Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Normal
Myelocyte*
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Additional Image 1
![](/images/scope_icon.gif) › Microscopic Features:- 2-3x larger than a mature RBC
- Intermediate nuclear to cytoplasmic ratio (more cytoplasm than promyelocyte)
- Eccentrically placed oval Nucleus (no nuclear indentation) with more mature chromatin (clumped)
- Perinuclear clearing is common
- Nucleoli are absent (Note: absent nucleoli from this stage onward)
- More cytoplasm with only rare or absent primary (azurophilic) granules
- Secondary (specific) granules of neutrophilic (lilac), eosinophilic (red-orange), or basophilic (blue) color are present based on precursor type
![](/images/normal_icon.gif) › Normal % blood-PB, marrow-BM, lymphoid tissue-LN:- PB: None
- BM: Scattered (~10%)
- LN: None
![](/images/resemble_icon.gif) › May Resemble:
![](/images/ddx_icon.gif) › Differential Diagnoses:
If in blood or increased numbers in bone marrow: Chronic Myelogenous Leukemia (CML) Leukemoid reaction Post-GCSF therapy Chronic Neutrophilic Leukemia |
![](/images/immuno_icon.gif) › Classic Immunophenotype:- CD34-
- CD117-
- HLA-DR-
- CD13+
- CD33+
- CD15+
- CD11b+/-
- CD16-
![](/images/cartoon_icon.gif) › Cartoon Image:
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![RBC](/images/rbc_clear.gif) for direct comparison![](/images/misc_icon.gif) › Misc:- Myelocyte bulge (increased myelocytes) is commonly noted in CML patients
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