Cited by 317Mast cells and histamineGastrointestinal Tumor Research and TreatmentHistiocytic Disorders and Treatments

Updated Diagnostic Criteria and Classification of Mast Cell Disorders: A Consensus Proposal

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Valent, Peter, Akin, Cem, Hartmann, Karin, Alvarez-Twose, Ivan, Brockow, Knut, Hermine, Olivier, Niedoszytko, Marek, Schwaab, Juliana +32 more·2021·HemaSphere

Abstract

Mastocytosis is a hematologic neoplasm characterized by expansion and focal accumulation of neoplastic mast cells (MC) in diverse organs, including the skin, bone marrow (BM), spleen, liver, and gastrointestinal tract. The World Health Organization classification divides the disease into prognostically distinct variants of cutaneous mastocytosis (CM) and systemic mastocytosis (SM). Although this classification remains valid, recent developments in the field and the advent of new diagnostic and prognostic parameters created a need to update and refine definitions and diagnostic criteria in MC neoplasms. In addition, MC activation syndromes (MCAS) and genetic features predisposing to SM and MCAS have been identified. To discuss these developments and refinements in the classification, we organized a Working Conference comprised of experts from Europe and the United States in August 2020. This article reports on outcomes from this conference. Of particular note, we propose adjustments in the classification of CM and SM, refinements in diagnostic criteria of SM variants, including smoldering SM and BM mastocytosis (BMM), and updated criteria for MCAS and other conditions involving MC. CD30 expression in MC now qualifies as a minor SM criterion, and BMM is now defined by SM criteria, absence of skin lesions and absence of B- and C-findings. A basal serum tryptase level exceeding 20 ng/mL remains a minor SM criterion, with recognition that hereditary alpha-tryptasemia and various myeloid neoplasms may also cause elevations in tryptase. Our updated proposal will support diagnostic evaluations and prognostication in daily practice and the conduct of clinical trials in MC disorders.

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Crossref · 10.1097/hs9.0000000000000646

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  • Well-differentiated SM (WDSM) is not recognized as an independent subtype according to 2022 ICC and WHO 5th Edition.

    “Well-differentiated SM (WDSM) is a variant of systemic mastocytosis not recognized as an independent subtype according to 2022 ICC and WHO 5th Edition.”

    From Defining “Normal” basal serum tryptase levels: a context-dependent approach to improve diagnostics in systemic mastocytosis (2025) · cites this paper as [10]

    The ‘Impact of WD MC morphology’ section says well-differentiated morphology can occur across forms of systemic mastocytosis and should be appended to the diagnosis and WHO variant, rather than treated as an independent subtype. But this 2021 consensus proposal does not establish what the 2022 ICC or WHO 5th Edition classifications recognize. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • A recent proposal suggested normalizing BST value by dividing it by the number of extra copies of the TPSAB1 gene plus one.

    “A recent proposal (10), also received by the 5th WHO classification (8), suggested normalizing BST value by dividing it by the number of extra copies of the TPSAB1 gene, encoding alpha tryptase, plus one.”
  • If another hematological neoplasm is present, the baseline serum tryptase ≥ 20 ng/mL minor criterion for systemic mastocytosis is no longer valid, and in the case of HαT, the tryptase level should be adjusted.

    “Importantly, if another hematological neoplasm is present, this criterion is no longer valid, and in the case of HαT, the tryptase level should be adjusted [56].”
  • Tryptase is correlated with disease severity since tryptase serves as a B-finding if it is above 200 ng/mL (adjusted for TPSAB1 status).

    “It is however correlated with disease severity since tryptase serves a B-finding if it is above 200 ng/mL (adjusted for the TPSAB1 status) [56,72].”
  • Mastocytosis was diagnosed using current World Health Organization criteria.

    “A diagnosis of mastocytosis was obtained using current World Health Organization criteria.17,18”

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Research works printed but not linked: 3

  1. [7]Valent P Horny H-P Li CY. Mastocytosis (mast cell disease). In: Jaffe ES Harris NL Stein H Vardiman JW, eds. World Health Organization (WHO) Classification of Tumours. Pathology & Genetics. Tumours of Haematopoietic and Lymphoid Tissues. Lyon, France: IARC Press Lyon; 2001: 291– 302.
  2. [8]Horny HP Akin C Metcalfe DD. Mastocytosis (mast cell disease). In: Swerdlow SH Campo E Harris NL, eds. World Health Organization (WHO) Classification of Tumours. Pathology & Genetics. Tumours of Haematopoietic and Lymphoid Tissues. Lyon, France: IARC Press; 2008; 54– 63.
  3. [9]Horny HP Akin C Arber D. Mastocytosis. In: Swerdlow SH Campo E Harris NL, eds. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. Lyon, France: IARC Press; 2017: 62– 69.

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Authors
Valent, P., Akin, C., Hartmann, K., Alvarez-Twose, I., Brockow, K., Hermine, O., Niedoszytko, M., Schwaab, J., Lyons, J. J., Carter, M. C., Elberink, H. O., Butterfield, J. H., George, T. I., Greiner, G., Ustun, C., Bonadonna, P., Sotlar, K., Nilsson, G., Jawhar, M., Siebenhaar, F., Broesby-Olsen, S., Yavuz, S., Zanotti, R., Lange, M., Nedoszytko, B., Hoermann, G., Castells, M., Radia, D. H., Muñoz-Gonzalez, J. I., Sperr, W. R., Triggiani, M., Kluin-Nelemans, H. C., Galli, S. J., Schwartz, L. B., Reiter, A., Orfao, A., Gotlib, J., Arock, M., Horny, H.-P., & Metcalfe, D. D.
Affiliations
  • Ludwig Boltzmann Institute for Hematology and Oncology (AT)
  • University of Michigan (US)
  • University of Basel (CH)
  • Instituto de Estudios de Mastocitosis de Castilla La Mancha (CLMast) and CIBERONC, Hospital Virgen del Valle, Toledo, Spain
  • Technical University of Munich (DE)
  • Hôpital Necker-Enfants Malades (FR)
  • Gdańsk Medical University (PL)
  • University Medical Centre Mannheim (DE)
  • National Institutes of Health (US)
  • University Medical Center Groningen (NL)
  • Mayo Clinic (US)
  • Hospital Virgen del Valle (ES)
  • Division of Hematology, Oncology and Cell Therapy, Department of Medicine, The Coleman Foundation Blood and Marrow Transplant Center at Rush University Medical Center, Chicago, Illinois, USA
  • Azienda Ospedaliera Universitaria Integrata Verona (IT)
  • Paracelsus Medical University (AT)
  • Karolinska University Hospital (SE)
  • Humboldt-Universität zu Berlin (DE)
  • Department of Dermatology and Allergy Centre, Odense University Hospital, Odense, Denmark
  • Department of Dermatology, Venereology and Allergology, Medical University of Gdansk, Poland
  • Munich Leukemia Laboratory (Germany) (DE)
  • Brigham and Women's Hospital (US)
  • Guy's and St Thomas' NHS Foundation Trust (GB)
  • Servicio Central de Citometria, Centro de Investigacion del Cancer (IBMCC; CSIC/USAL) Instituto Biosanitario de Salamanca (IBSAL) and Department of Medicine, University of Salamanca, Spain
  • University of Salerno (IT)
  • Department of Haematology, University Medical Center Groningen, University of Groningen, The Netherlands
  • Stanford Medicine (US)
  • Virginia Commonwealth University (US)
Corresponding author
Valent, Peter
Venue
HemaSphere
Publisher
Wiley
Published
2021-10-13
Volume
5
Issue
11
Pages
e646
ISSN
2572-9241 (ISSN-L)
OpenAlex
W3206166311
Cited by
317
References
107
Citations by year
2026: 42 · 2025: 75 · 2024: 71 · 2023: 79 · 2022: 48 · 2021: 1
FWCI
5.10
Type
journal article
Language
en
Open access
Locations
  • HemaSphere (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • University of Southern Denmark Research Portal (University of Southern Denmark) (publishedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • edoc (University of Basel) (submittedVersion)
  • mediaTUM – the media and publications repository of the Technical University Munich (Technical University Munich) (submittedVersion)
  • mediaTUM – the media and publications repository of the Technical University Munich (Technical University Munich) (submittedVersion, other-oa)
  • University of Groningen research database (University of Groningen / Centre for Information Technology) (submittedVersion, cc-by-nc-nd)
Funders
  • Austrian Science Fund (P32470‐B, #F4704-B20, P 32470)
  • Cancerfonden
  • Vetenskapsrådet
  • National Institute of Allergy and Infectious Diseases
  • NHLBI Division of Intramural Research
Topics
  • Life Sciences › Immunology and Microbiology › Immunology › Mast cells and histamine
  • Health Sciences › Medicine › Gastroenterology › Gastrointestinal Tumor Research and Treatment
  • Health Sciences › Medicine › Physiology › Histiocytic Disorders and Treatments
Keywords
mastocytosis, mast cell disease, diagnostic criteria, classification, cutaneous mastocytosis, systemic mastocytosis, mast cell activation syndrome, bone marrow mastocytosis, CD30 expression, serum tryptase, hereditary alpha-tryptasemia, prognostic criteria

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