Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Myeloid ›› Megakaryocytes & Precursors ›› Abnormal
Megakaryoblast (Increased)
›Microscopic Features:
- 3-4x larger than a mature RBC
- High nuclear to cytoplasmic ratio
- Round Nucleus with immature chromatin (not clumped)
- Prominent nucleoli
- Cytoplasm is pale blue with occasional cytoplasmic blebs (want-to-be platelets)
›Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
- PB: None
- BM: Rare (<1%)
- LN: None
›May Resemble:
›Differential Diagnoses:
If in blood or increased numbers in bone marrow:
Acute Megakaryoblastic leukemia (AML-M7)
Transient Myelopoeisis (usually asosciated with some newborns with Down Syndrome)
Acute Megakaryoblastic leukemia (AML-M7)
Transient Myelopoeisis (usually asosciated with some newborns with Down Syndrome)
›Classic Immunophenotype:
- CD41+
- CD42+
- CD61+
›Cartoon Image:
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›Misc:
Transient Myelopoeisis shows increased megakaryoblasts in blood and/or marrow of a newborn down syndrome patient and may mimic an AML-M7 (Acute Megakaryoblastic Leukemia)