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General Pediatric Leukemia


What is Leukemia?

Leukemias are due to proliferation of malignant blast cells.

Malignancy of blood-forming tissue, typically the white blood cells.

From Greek:  “leuk”  = white   “emia” = blood

“Blast”refers to a malignant leukemia cell

However, normal bone marrow can have a few normal blasts that are not malignant.

  • Under 5% blasts can be normal
  • Leukemia has by definition > 25% blasts at diagnosis.


The diagram below shows the normal development of the different blood cell lines from bone marrow stem cells:


Blasts in leukemia:  

  • Fail to mature but keep replicating and dividing
  • Crowd out the normal cells
  • Appear “Monomorphic”  - all cells look similar


Bone marrow aspirate in ALL (the purple cells are leukemic blast cells):



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