Table 3.

Criteria for the diagnosis of systemic mastocytosis^* (adapted from [10])

Major criterion

Multifocal dense infiltrates of mast cells in bone marrow and/or other extracutaneous organs

Minor criteria More than 25% of the mast cells in the bone marrow smears or tissue biopsy sections are spindle shaped or display atypical morphology Detection of a codon 816 c-kit point mutation in blood, bone marrow, or lesional tissue Mast cells in the bone marrow, blood, or other lesional tissue expressing CD25 or CD2 Baseline total tryptase level persistently greater than 20 ng/ml

^*One major and one minor; or three minor criteria are needed for the diagnosis of systemic mastocytosis