Table 4.

Diagnostic criteria for SM by 2022 ICC and the WHO 5th Edition (Adopted from [9,10,49]).

	2022 ICC	WHO 5th Edition
Major criterion	Multifocal dense infiltrates of tryptase- and/or CD117 positive MCs (≥15 MCs in aggregates) detected in sections of bone marrow and/or other extracutaneous organ(s).	Multifocal dense infiltrates of MCs (≥15 MCs in aggregates) in bone marrow biopsies and/or in sections of other extracutaneous organ(s).
Minor criteria	In bone marrow biopsy or in section of other extracutaneous organs, >25% of MCs are spindle shaped or have an atypical immature morphology.	At least 25% of all MCs are atypical cells (type I or type II) on bone marrow smears or are spindle-shaped in MC infiltrates detected in sections of bone marrow or other extracutaneous organs.
	KIT D816V mutation or other activating KIT mutation detected in bone marrow, peripheral blood, or other extracutaneous organs.	Activating KIT point mutation(s) at codon 816 or in other critical regions of KIT in bone marrow or another extracutaneous organ(s).
	MCs in bone marrow, peripheral blood, or other extracutaneous organs express CD25, CD2, and/or CD30, in addition to MC markers.	MCs in bone marrow, blood, or another extracutaneous organs express one or more of the following: CD2 and/or CD25 and/or CD30.
	Elevated serum tryptase level, persistently >20 ng/mL. In cases of SM-AMN, an elevated tryptase does not count as an SM minor criterion.	Baseline serum tryptase concentration > 20 ng/mL (in the case of an unrelated myeloid neoplasm, an elevated tryptase does not count as an SM criterion. In the case of a known HαT, the tryptase level should be adjusted).
NOTE:	The major criterion alone is enough, or in the absence of the major criterion, at least 3 of the 4 minor criteria must be present.	The major plus at least 1 minor, or 3 minor criteria must be fulfilled for diagnosis of SM.