Treatment refractory mast cell leukemia with dominant gastrointestinal manifestation and concomitant skin symptoms: A case report

Table 2 Systemic mastocytosis diagnostic criteria

Criteria	Description
Major criterion	Multifocal dense infiltrates of mast cells MCs (≥ 15 MCs in aggregates) in bone marrow trephine biopsies and/or in sections of other extracutaneous organ(s)
Minor criteria	(1) Presence of atypical mast cells in bone marrow smears or spindle-shaped mast cells in biopsies of internal organs (except skin) constituting > 25% of all types of mast cells
	(2) Presence of KIT gene mutation in the bone marrow or another extracutaneous organ(s)
	(3) MCs in bone marrow, blood, or other extracutaneous organs expressing CD25 and/or CD2 and/or CD30
	(4) Serum tryptase concentration > 20 ng/ml (does not apply to patients with other malignancies of the hematopoietic system accompanying mastocytosis)
According to WHO 2022, a major and one minor OR at least three minor SM criteria must be fulfilled to establish a diagnosis
According to ICC 2022, a major criterion or at least 3 minor SM criteria must be fulfilled to establish a diagnosis

MCs: Mast cells; SM: Systemic mastocytosis; ICC: International consensus classification; OR: Odds ratio; WHO: World Health Organization.