Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Myeloid ›› Megakaryocytes & Precursors ›› Abnormal
Staghorn-shaped Megakaryocyte
›Microscopic Features:
- 10-30x larger than a mature RBC
- Lower nuclear to cytoplasmic ratio because of increased cytoplasm
- Multilobated Nucleus (6-10 lobes with a Staghorn configuration)
- Nucleoli are absent
- Cytoplasm is abundant and light blue which 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:
Myeloproliferative neoplasm (specifically Essential Thrombocythemia)
Post Chemotherapy
MDS (rarely)
Myeloproliferative neoplasm (specifically Essential Thrombocythemia)
Post Chemotherapy
MDS (rarely)
›Classic Immunophenotype:
- CD41+
- CD42+
- CD61+
›Cartoon Image:
Click and drag
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)