Table 3. Diagnostic criteria for systemic mastocytosis.

Adapted from Valent P et al. [13]

MCs - mast cells, BM - bone marrow

Major criterion

Multifocal, dense MCs infiltrates in BM or other extracutaneous organs (>15 MCs in aggregates)

Minor criteria

BM with >25% of all MC infiltrates are immature MCs or with atypical morphology

Activating cKIT mutation (D816V) in blood/BM/extracutaneous organ

Increased persistent serum tryptase >20 ng/ml (in the absence of associated myeloid neoplasm)

MCs in BM/blood/extracutaneous organ express one or more of CD25 and/or CD2 and/or CD30