Mastocytosis & Mast Cell Disorders Definition Signs & Symptoms Diagnosis Treatment Symptom Management Related Conditions FAQ
Mastocytosis is defined as a myeloproliferative neoplastic (mpn) stem cell disorder, caused by an over-abundance of good immune system cells called mast cells and the release of mast cell mediators. These cells may also be misshapen or malformed, further contributing to their dysfunction.1 Mastocytosis presents in cutaneous (skin) and systemic (internal) forms. Patients of all ages and genders may present with one or both forms of the disease. The World Health Organization (WHO) has classified mastocytosis as having 7 variants with 13 subvariants2 & 3. See table below (Note: we have linked to photographic images of our members photos of cutaneous forms):-

Mastocytosis Variant Mastocytosis Subvariant
Cutaneous mastocytosis (CM)
  • Maculopapular CM (MPCM) / Urticaria Pigmentosa (UP) (*common form)
  • Telangiectasia macularis eruptiva perstans (TMEP)  (*rarest skin form)
  • Diffuse CM (DCM)  (*rare infant/child form)
  • Mastocytoma (*infant/child form)
  • Indolent systemic mastocytosis (ISM)
  • Smouldering SM (SSM)
  • Isolated bone marrow mastocytosis (BMM)
  • Systemic mastocytosis with an associated clonal hematological non-mast cell lineage disease (SM-AHNMD/SM-AHD)
  • SM-Acute myeloid leukemia
  • SM-Myelodysplastic syndromes
  • SM-Chronic myelomonocytic leukemia
  • SM-Non Hodgkin Lymphoma
  • SM-Myeloproliferative disease
  • SM-Hypereosinophilic syndrome
  • Aggressive systemic mastocytosis (ASM)  
    Mast cell leukemia (MCL) Aleukemic MCL
    Mast cell sarcoma  
    Extracutaneous mastocytosis  
    Mast Cell Activation Syndrome (MCAS) is constantly under discussion with ongoing research in the medical community worldwide. The current definition is that MCAS is caused by abnormal mast cells4 and/or abnormal mast cell activity5. We recommend viewing the Mast Cell Activation medical lecture we hosted in June 2011 at University of Toronto, Ontario, Canada. See our Physicians & Emergency Literature page to view here.

    Idiopathic Anaphylaxis (IA) is defined as anaphylaxis which occurs without an identifiable trigger6. Photographic images of our members in the throes of anaphylaxis may be viewed here.

    1. Arock,M - Laboratory of Cellular and Molecular Hematology, Faculty of Pharmacy, Paris:  Mastocytosis: classification, laboratory diagnosis and treatment   Annals de Biologie Clinique, Epileptic Disorders. Volume 62, Number 6, 657-69 November-December 2004. [Open Access - French]
    2. McNeill,O., Katelaris,C.:  Disease Summaries - Mastocytosis: Where are we now? World Allergy Organization July 2011. [Open Access]
    3. Nguyen,N.:  Pathology: Mastocytosis (Mast Cell Diseases). The University of Texas, Health Science Center at Houston 2012. [Open Access]
    4. Molderings,G., Brettner,S., Homann,J., Afrin,L.:  Mast cell activation disease: a concise practical guide for diagnostic workup and therapeutic options. J Hematology & Oncology March 2011. [Open Access]
    5. Valent.P., Horny,H-P., Triggiani.M., Arock,M.:   Clinical and Laboratory Parameters of Mast Cell Activation as Basis for the Formulation of Diagnostic Criteria Int Arch Allergy Immunol 2011;156:119-127. May 2011. [Open Access]
    6. Greenberger,P.A:  Idiopathic anaphylaxis Immunol Allergy Clin North Am.;27(2):273-93, vii-viii. May 2007. [Abstract]

    Copyright  2011-2014 Mastocytosis Society Canada. All Rights Reserved.
    Charity Registration Number: 848190062RR0001

    Disclaimer, Privacy & Copyright