2. Academic Validation
  3. Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal

Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal

  • Ann Oncol. 2014 Sep;25(9):1691-1700. doi: 10.1093/annonc/mdu047.
P Valent 1,  K Sotlar 2,  W R Sperr 3,  L Escribano 4,  S Yavuz 5,  A Reiter 6,  T I George 7,  H C Kluin-Nelemans 8,  O Hermine 9,  J H Butterfield 10,  H Hägglund 11,  C Ustun 12,  J L Hornick 13,  M Triggiani 14,  D Radia 15,  C Akin 16,  K Hartmann 17,  J Gotlib 18,  L B Schwartz 19,  S Verstovsek 20,  A Orfao 4,  D D Metcalfe 21,  M Arock 22,  H-P Horny 2
Affiliations

Affiliations

  • 1 Division of Hematology, Department of Medicine I, Medical University of Vienna, Vienna, Austria. Electronic address: [email protected].
  • 2 Institute of Pathology, Ludwig-Maximilians-University, Munich, Germany.
  • 3 Division of Hematology, Department of Medicine I, Medical University of Vienna, Vienna, Austria.
  • 4 Servicio Central de Citometria, Centro de Investigacion del Cancer (IBMCC; CSIC/USAL) and Department of Medicine, University of Salamanca, Salamanca, Spain.
  • 5 Division of Hematology, Department of Internal Medicine, University of Istanbul, Turkey.
  • 6 III. Medizinische Klinik, Universitätsmedizin Mannheim, Universität Heidelberg, Mannheim, Germany.
  • 7 Department of Pathology, University of New Mexico, Albuquerque, USA.
  • 8 Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
  • 9 Imagine Institute Université Paris Descartes, Sorbonne, Paris Cité, Centre national de référence des mastocytoses, Paris, France.
  • 10 Division of Allergic Diseases, Mayo Clinic, Rochester, USA.
  • 11 Hematology Center Karolinska, Karolinska University Hospital, Stockholm, Sweden.
  • 12 Division of Hematology-Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis.
  • 13 Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
  • 14 Division of Allergy and Clinical Immunology, University of Salerno, Salerno, Italy.
  • 15 Department of Haematology, Guys and St Thomas' NHS Foundation Trust, Guys Hospital, London, UK.
  • 16 Division of Allergy and Immunology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
  • 17 Department of Dermatology, University of Cologne, Cologne, Germany.
  • 18 Stanford Cancer Center, Stanford University School of Medicine, Stanford.
  • 19 Department of Internal Medicine, Division of Rheumatology, Allergy & Immunology, Virginia Commonwealth University, Richmond.
  • 20 Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston.
  • 21 Laboratory of Allergic Diseases, NIAID, NIH, Bethesda, USA.
  • 22 LBPA CNRS UMR8113, Ecole Normale Supérieure de Cachan, Cachan, France.
PMID: 24675021 DOI: 10.1093/annonc/mdu047
Abstract

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. In a subset of patients, circulating MCs are detectable. A major differential diagnosis to MCL is myelomastocytic leukemia (MML). Although criteria for both MCL and MML have been published, several questions remain concerning terminologies and subvariants. To discuss open issues, the EU/US-consensus group and the European Competence Network on Mastocytosis (ECNM) launched a series of meetings and workshops in 2011-2013. Resulting discussions and outcomes are provided in this article. The group recommends that MML be recognized as a distinct condition defined by mastocytic differentiation in advanced myeloid neoplasms without evidence of SM. The group also proposes that MCL be divided into acute MCL and chronic MCL, based on the presence or absence of C-Findings. In addition, a primary (de novo) form of MCL should be separated from secondary MCL that typically develops in the presence of a known antecedent MC neoplasm, usually aggressive SM (ASM) or MC sarcoma. For MCL, an imminent prephase is also proposed. This prephase represents ASM with rapid progression and 5%-19% MCs in BM smears, which is generally accepted to be of prognostic significance. We recommend that this condition be termed ASM in transformation to MCL (ASM-t). The refined classification of MCL fits within and extends the current WHO classification; and should improve prognostication and patient selection in practice as well as in clinical trials.

Keywords

KIT D816V; leukemia; mast cells; mastocytosis; prognostication; tryptase.

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