The World Heath Organization (WHO) developed criteria for the diagnosis of mast cell leukemia.


Criteria for the diagnosis of mast cell leukemia:

(1) meets the criteria for systemic mastocytosis

(2) biopsy shows a diffuse infiltration by atypical, immature mast cells, usually showing an interstitial pattern

(3) bone marrow aspirate shows >= 20% mast cells


Percent Mast Cells in Peripheral Blood


>= 10%

mast cell leukemia

< 10%

aleukemic mast cell leukemia



• The percent bone marrow mast cell is one of the minor criteria for systemic mastocytosis.


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