Genes involved in the pathogenesis of mast cell leukemia include KIT D816V and non-KIT D816V.^[1][2][3] There are no characteristic findings of mast cell leukemia on gross pathology.^[4] On microscopic histopathological analysis, multifocal sheets and clusters of mast cells in bone marrow sections are findings of mast cell leukemia.^[5]

• Mutation of KIT is a hallmark of the mast cell leukemia.
• Adult-type human mastocytosis is characterized by mutations in c-KIT at codon 816, which cause constitutive activation of KIT kinase.
• Different classes of activating KIT mutations respond differentially to KIT inhibitors depending on the site and type of mutation.
• D816V c-KIT mutation is the most frequent mutation, found in more than 80% of adult patients with systemic mastocytosis especially in the aggressive forms with a frequency of more than 95% in mast cell leukemia patients.^[1]
• Mutations in SRSF2, ASXL1 or RUNX1 are founded in mast cell leukemia patient.^[6]
• The majority patients with mast cell leukemai have signs of organ damage.^[6]

Genes involved in the pathogenesis of mast cell leukemia include:^[1][2][3]

• KIT D816V
• non-KIT D816V

Mast cell leukemia may be associated with systemic mastocytosis.^[2]

There are no characteristic findings of mast cell leukemia on gross pathology. Gross specimens are not seen typically.^[4]

On microscopic histopathological analysis, findings of mast cell leukemia include:^[5]

• Multifocal sheets of mast cells
• Clusters of mast cells

• 
  _{Peripheral blood showing mast cell leukemia.^[7]}

• Atypical mast cells express multiple surface antigens such as:^[1]

• CD117
• CD11c
• CD13
• CD29
• CD33
• CD44
• CD45
• CD63
• CD68
• CD71
• CD2
• CD22
• CD25
• CD54

• The role of these antigens is however not yet understood.
• CD2 and CD25 antigens are important markers.

• Their positivity on the surface of mast cells constitute minor criteria for the diagnosis of mast cell disease.

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