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

Erythroid Leukemia (AML M6)*


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Additional Image 1

› Microscopic Features:

• Marked increase in immature erythroid precursors
• Background of increased erythroid precursors with dysplastic features is also common (Note: the multinucleated erythroid precursor on the left side of the image)

› Normal % blood-PB, marrow-BM, lymphoid tissue-LN:

• PB: None
• BM: None
• LN: None

› May Resemble:

• Myeloblast [Compare]
• Erythroid hyperplasia

› Differential Diagnoses:

AML (other subtypes) MDS

› Classic Immunophenotype:

• Pure Eythroid-type:
• CD34-
• HLADR-
• CD117+/-
• CD235a (Glycophorin A)+
• Hemoglobin A +
• MPO-
• ---------------------------
• Erythroid/Myeloid type
• *Erythroblasts are usually:
• CD235a (Glycophorin A)+
• Hemoglobin A +
• CD71 dim or -
• MPO-
• *Myeloblasts may be:
• CD34+
• CD117+
• MPO-/+

› Cartoon Image:


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for direct comparison
› Misc:

• 2 types: In "Pure Erythroid"-type (less common) the bone marrow is comprised of 80% or more erythroid precursors while the "Erythroid/Myeloid" type has 50% or more erythroid precursors in the bone marrow with 20% or more myeloblasts (% myeloblasts is calculated in the non-erythroid cells) Note: As opposed to other AMLs which usually have 20% or more myeloblasts (as calculated from the total number of nucleated cells), in the Erythroid/Myeloid type of AML-M6: %myeloblasts are calculated after subtracting the background erythroid precursors.