AML (M1)

Acute Myeloblastic Leukemia

• Predominantly poorly differentiated myeloblasts.
  
  
• Nucleus has fine lacy chromatin pattern. Distinct nucleoli. Moderate amount of cytoplasm, but may vary.
  
  
• FAB criteria less than 10% of leukemic cells have azurophilic granules (primary granules) when observed on Romanowsky stained smear.
  
  
• Peroxidase or Sudan Black B reaction must demonstrate at least 3% positivity (in the population of abnormal cells) to exclude lymphoblastic leukemia and less than 50% positivity to keep leukemia within M1 subgroup.
  
  
• NSE reaction positive in less than 20% of cells.
  
  
• When present, Auer rods helpful in distinguishing M1 from ALL (L2 variant).

PROGNOSIS

Poor