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Table 3 World Health Organization criteria for systemic mastocytosis

From: Critical care management of systemic mastocytosis: when every wasp is a killer bee

Major criterion

- The existence of 15 or more multifocal mast cell clusters in the bone marrow or in other tissue biopsies

Minor criteria

- Basal tryptase level of more than 20 ng/mL

- Either (a) more than 25% of mast cells in infiltrates of bone marrow or other extracutaneous organs are atypical or spindle-shaped or (b) more than 25% of mast cells in bone marrow aspirate are immature or atypical.

- Co-expression of CD117 with CD25 or CD2 (or both) on mast cells

- Codon 816 mutation in the C-KIT gene

  1. To establish the diagnosis of systemic mastocytosis, either one major and two minor or three minor World Health Organization criteria have to be fulfilled. Patients who have a history of mast cell activation symptoms without skin lesions but who do not fully meet diagnostic criteria for systemic mastocytosis are classified as having mast cell activation syndrome [9, 17]
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Critical Care

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