Table 1.

Diagnostic criteria for systemic mastocytosis

Major	Multifocal dense infiltrates of mast cells in bone marrow or other extracutaneous organ sections (>15 mast cells aggregating)
Minor	>25 % mast cells in tissue sections or bone marrow aspirate smears that are spindle-shaped, immature or have atypical morphology
	C-kit point mutation at codon 816 V detected in bone marrow, blood, or another extracutaneous organ
	Expression of CD2 and/or CD25 in neoplastic mast cells
	Baseline serum tryptase persistently >20 ng/mL (not valid in presence of another non–mast cell clonal disorder)