Table 1. WHO 2008 classification of mastocytosis.

Category of Mastocytosis	Abbreviation	Subvariants / subclasses
Cutaneous mastocytosis	CM	Urticaria pigmentosa (UP) Maculopapular CM (MPCM) Diffuse CM Mastocytoma of skin (MIS)
Indolent mastocytosis	ISM	Smoldering SM (SSM) Isolated bone marrow mastocytosis Well differenciated mastocytosis
Systemic mastocytosis with associated non-hematological mast cell disease	SM-AHNMD	SM-acute myeloid leukemia (SM-AML) SM-myelodysplastic syndrome (SM-MDS) SM-myeloproliferative neoplasm (SM-MPN) SM-chronic myelomonocytic leukemia (SM-CMML) SM-chronic eosinophilic leukemia (SM-CEL) SM-non-Hodgkin lymphoma (SM-NHL) SM-myeloma
Aggressive systemic mastocytosis	ASM	Lymphadenopathic SM with eosinophilia
Mast cell leukemia	MCL	Aleukemic MCL
Mast cell sarcoma	MCS
Extracutaneous Mastocytoma	ECM

Adapted and complied from Horny HP, Metcalfe DD, Bennett JM, et al. Mastocytosis. In: Swerdlow SH, Campo E, Harris NL, et al editors. WHO Classification of tumors of haematopoietic and lymphoid tissues. Lyon (France): IARC Press; 2008. p. 54–63, and from Bibi S, Langenfeld F, Jeanningros S, Brenet F, Soucie E, Hermine E, Damaj G, Dubreuil P, Arock M, Molecular Defects in Mastocytosis KIT and Beyond KIT, Immunol Allergy Clin N Am 2014. p. 239–262