. 2021 Oct 19;22(20):11270. doi: 10.3390/ijms222011270

Table 1.

Classification of Disorders Associated with Mast Cells.

1.
MASTOCYTOSIS
- a.
  Cutaneous Mastocytosis *
  1. Diffuse cutaneous mastocytosis
  2. Maculopapular mastocytosis (Urticaria Pigmentosa)
  3. Cutaneous mastocytoma
- b.
  Systemic Mastocytosis *
  1. Indolent systemic mastocytosis (ISM) [includes bone marrow mastocytosis]
  2. Smoldering systemic mastocytosis (SSM)
- c.
  Advanced Systemic Mastocytosis *
  1. Aggressive systemic mastocytosis (ASM)
  2. Mastocytosis with associated hematological neoplasia (SM-AHN)
  3. Mast cell leukemia (including aleukemic leukemia)
- d.
  Nonclonal disorders: Mast cell sarcoma
2.
MAST CELL ACTIVATION SYNDROME (MCAS)
- a.
  Primary Mast cell Activating Syndrome/Monoclonal Mast Cell Activating Syndrome (MMAS)/Clonal Mast Cell Activating Syndrome (CMCAS) *
- b.
  Secondary Mast Cell Activating Syndrome (IgE-mediated allergy, autoim-munity, chronic infection, nematode infestation, underlying neoplasia)
- c.
  Idiopathic Mast Cell Activation Syndrome (no obvious etiology)
- d.
  Combined primary disorder with allergy-triggered mast cell activation
3.
IDIOPATHIC ANAPHYLAXIS (IA)
1. No obvious allergens (cryptic allergens and mammalian meat allergy to be excluded)
2. Idiopathic anaphylaxis associated with bone marrow mastocytosis and clon-ality *
3. IA associated with CMCAS and/or hereditary alpha-tryptasemia *
4.
REACTIONS TO HYMENOPTERA VENOM AND CLONAL MAST CELL DIS-EASE
1. Associated with bone marrow mastocytosis and clonality *
2. Associated with MCAS and/or clonality *
5.
BONE MARROW MASTOCYTOSIS
6.
HEREDITARY ALPHA TRYPTASEMIA
1. Isolated condition
2. Associated with CMCAS, SM and variants and IA
7.
COMBINED DISORDERS (Various combination of above conditions)

* = Associated with clonality (D816V mutation, other mutations or associated with aberrant mast cell expression of CD2 or CD25 on cell surface).