9742/3 Mast cell leukaemia


Tumours of haematopoietic and lymphoid tissues
ICD-O-3 topography code: C42 and C77
ICD10: C94.3

/span>ast cell leukaemia (MCL) meets the diagnosic criteria criteria for systemic mastocytosis (SM). Bone marrow biopsy shows a diffuse infiltration, usually compact, by atypical, immature mast cells. Bone marrow aspirate smears show 20% or more mast cells. In typical MCL, mast cells account for 10% or more of peripheral blood white cells.
Rare variant: aleukaemic mast cell leukaemia ? as above, but <10% of white blood cells are mast cells. Usually without skin lesions.