Introduction
Mast Cell Origin and Development
Mast Cell Tissue Homing
Mast Cell Mediators and Receptors
Stem Cell Factor
SCF-KIT Interaction and Mediated Signaling
Molecular Mechanisms
Symptoms of Mediator Release
MCAS
Clinical Classification
Variant term | Subvariants | Features |
---|---|---|
Cutaneous mastocytosis (CM) | Prevalence ~85% Organ involved: skin [66] Molecular abnormality: KIT D816F, KIT E839K, KIT D816Y [3] | |
Urticaria pigmentosa (UP) | Characterized by fixed, reddish brown lesions which occur as maculo-papules, plaques, nodules or blisters [99]. | |
Maculopapular CM (MPCM) Adulthood-onset mastocytosis Childhood-onset mastocytosis | Small monomorphic lesions | |
Diffuse CM (DCM) | Rare, severe, variant which occurs mainly in infants. Blistering generalized erythroderma, nodules, and plaques are observed [100]. | |
Skin mastocytoma | ||
Indolent systemic mastocytosis (ISM) | Smoldering SM | No evidence of organ dysfunction [68]. Therapy: antimediator therapy [3] Prevalence ~10% [5] |
Isolated bone marrow mastocytosis | ||
Systemic mastocytosis with an associated clonal hematologic non-mast cell Lineage disease (SM-AHNMD) | SM-AML | Prevalence ~1% [5] |
SM-MDS | ||
SM-MPD | ||
SM-CMML | ||
SM-NHL | ||
Aggressive systemic mastocytosis (ASM) | Impairment of organ function, organomegaly (particularly splenomegaly), cachexia or osteolyses [76]. Therapy: chemotherapy and stem cell transplantation [3] Prevalence ~5% [5] | |
Mast cell leukemia (MCL) | Aleukemic MCL | Very aggressive [68]. Prevalence <1% [5] Therapy: chemotherapy and stem cell transplantation [3] |
Mast cell sarcoma | Aggressive neoplasm composed of cytologically malignant MCs presenting as a solitary mass [101]. Prevalence <1% [5] | |
Extracutaneous mastocytoma | Unifocal MC tumor with low-grade cellular atypia and non-destructive features [68] Prevalence <1% [5] |
Major | Multifocal infiltrates of MC in bone marrow sections or other extracutaneous organ(s) (>15 MCs in aggregate) |
---|---|
Minor | • More than 25% of BMMC or MCs of extracutaneous organ(s) are spindle-shaped. • KIT mutation at codon 816 in extracutaneous organ(s) • Presence of CD2+ and/or CD25+ BMMCs • Basal serum tryptase >20 ng/ml (not for patients with AHNMD-type disease) |