Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Myeloid ›› Megakaryocytes & Precursors ›› Abnormal
Dyslobated (Abnormal Lobation) Megakaryocyte
›Microscopic Features:
- 10-30x larger than a mature RBC
- Lower nuclear to cytoplasmic ratio because of increased cytoplasm
- Multilobated Nucleus (2-8 lobes on top of each other) with mature chromatin (clumped) but with disconnected lobe(s) (usually on the polar opposite end)
- Nucleoli are absent
- Cytoplasm is abundant and light blue and usually lacks granules
›Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
- PB: None
- BM: None
- LN: None
›May Resemble:
- Megakaryocyte (normal)
- Osteoclast
- Histiocytes and macrophages (specially multinucleated forms)
- Hodgkin Lymphoma Reed Sternberg cell
- Metastatic tumor cells
›Differential Diagnoses:
Associated with:
MDS
Post Chemotherapy
Toxin-induced
MDS
Post Chemotherapy
Toxin-induced
›Classic Immunophenotype:
- CD41+
- CD42+
- CD61+
›Cartoon Image:
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for direct comparison
for direct comparison
›Misc:
For Megakaryocytes with polar disconnected lobes think of MDS
For Megakaryocytes with Staghorn shape think of Essential Thrombocythemia (a Myeloproliferative neoplasm)
For Megakaryocytes with Staghorn shape think of Essential Thrombocythemia (a Myeloproliferative neoplasm)