Aggressive mature natural killer cell neoplasms: from epidemiology todiagnosis

Table 1 Natural killer cell neoplasms according to the World Health Organizationclassification of tumors of hematopoietic and lymphoid tissues

WHO classification, 2008	Disease entities	Putative cells of origin	Orphanet numbers	Synonyms in the Orphanet data base	ICD codes		Prevalence categories (/1.000.000)	[References]
					ICD-10	ICD-O-3
NK-cell neoplasms	Extranodal NK/T-cell lymphoma (NKTCL), nasal type	Mature NK-cells	86879	NK/T-cell lymphoma; Nasal T/natural killer-cell lymphoma;Angiocentric T-cell lymphoma; Lethal midline granuloma	C86.0	9719/3	<1-9	[19, 22–24]
NK-cell neoplasms	Aggressive NK-cell leukemia (ANKCL)	Mature NK-cells	86873	Aggressive NK-cell leukemia; Aggressive NK-cell lymphoma; NK-cellLGL leukemia; NK-cell large granular lymphocyte leukemia	C94.7	9948/3	<1-9	[20, 22–24]
Provisional entities	Chronic lymphoproliferative disorders of NK-cells (CLPD-NK)	Mature NK-cells	Not available	NK-cell LGL leukemia; NK-cell large granular lymphocyte leukemia(considered together with ANKCL)	Not available (C94.7)*	Not available (9831/3)**	Unknown	[21–24]
	NK-cell lymphoblastic leukemia / lymphoma	NK-, T- and/or myeloid precursor cells	Not available	Not available	Not available	Not available	Unknown	[22–25]

Abbreviations: ICD-10 International Statistical Classificationof Diseases and Related Health Problems (formerly designatedInternational Classification for Diseases), 10th revision, 2010, WorldHealth Organization (available in:http://apps.who.int/classifications/icd10/browse/2010/en;accessed in 2 February 2013); ICD-O-3 International StatisticalClassification of Diseases and Related Health Problems, for Oncology(formerly designated International Classification of Diseases forOncology, 3rd edition, 2000, World Health Organization (available in:http://www.who.int/classifications/icd/adaptations/oncology/en/index.html;accessed in 2 February 2013); WHO World HealthOrganization.
Blastic plasmacytoid dendritic cell neoplasm, also known asCD4⁺ CD56⁺ hematodermic neoplasm andpreviously designed blastic NK-cell lymphoma (Orpha:86870; ICD-10:C86.4, still referred as blastic NK-cell lymphoma; ICD-O: 9727/3) arisesfrom plasmacytoid dendritic cells and should no longer be considered aNK-cell malignancy [26].
* Considering the synonymous list, CLPD-NK, which include chronic NK-cellLGL leukemia cases, are considered together with ANKCL; ** According tothe proposal of the WHO classification, 2008, CLPD-NK should beconsidered together with T-LGLL in the ICD-O.

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