WHO Classification (2008):
As of 2008, acute myeloid leukemias have been classified into different subcategories based on the type of genetic abnormalities, type of myeloid cell type affected, and by cell characteristics:1
Acute myeloid leukemia with recurrent genetic abnormalities
Acute myeloid leukemia with myelodysplastic changes
Therapy related myeloid neoplasms
Acute myeloid leukemia, not otherwise specified (NOS)
Myeloid Proliferations related to Down syndrome
Blastic plasmacytoid dendritic cell neoplasm
Affected Age: Adults.2
Cells of myeloid lineage are affected:1
- Dendritic cells
AML Blasts Cell Features:3
Size: Myeloblasts are usually larger compared to lymphoblasts and have a consistent appearance.
Nucleoli: Prominent, 1-4 present
Chromatin: Loose open chromatin
Cytoplasm: Often abundant and granules may be visible
Auer Rods: may be present (stained faint pink with Wright’s stain)
Auer Rods are thought to be fused primary granules and are only found in myeloblasts. Presence of auer rods is distinctive of AML and can be used to differentiate the condition from ALL if it is present.1
Laboratory Results for AML:1,4,5
Myeloblasts ± Auer rods
May see hypogranular PLT, Giant PLT
Neutropenia (Can appear dysplastic)
May see Basophilia, Eosinophilia, Monocytosis
≥20% Myeloblasts ± Auer rods
Depending on the subgroup, cells may be positive for:
CD11b, CD13, CD14, CD33, CD34, CD117
1. Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, et al. editors. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues Volume 2. 4th ed. International Agency for Research on Cancer (IARC); 2008.
2. McKenzie SB. Introduction to hematopoietic neoplasms. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 424-45.
3. Gatter K, Cruz F, Braziel R. Introduction to leukemia and the acute leukemias. In: Clinical hematology and fundamentals of hemostasis. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 331-370.
4. Roquiz W, Gandhi P, Kini AR. Acute leukemias. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 543-60.
5. Bentley G, Leclair SJ. Acute Myeloid Leukemias. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 500-21.