Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Abnormal

Micro-Megakaryocyte*


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› Microscopic Features:

• 3-6x larger than a mature RBC
• Lower nuclear to cytoplasmic ratio because of increased cytoplasm
• Many are hypolobated (1-2 lobes) with a mature (clumped chromatin) nucleus
• 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) [Compare]
• Osteoclast
• Histiocyte
• Monocyte [Compare]
• Osteoblast
• Metastatic tumor cells
• Myelocyte [Compare]

› Differential Diagnoses:

Usually sssociated with: MDS Post Chemotherapy Etc.

› Classic Immunophenotype:

• CD41+
• CD42+
• CD61+

› Cartoon Image:


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for direct comparison
› Misc:

• May be associated with a myelodysplastic syndrome (MDS)