Aggressive mature natural killer cell neoplasms: from epidemiology todiagnosis

Table 4 Clinical staging systems used for aggressive NK-cell neoplasms

Staging system	Stages	Staging criteria	[References]
Ann Arbor staging system*	Stage I	Confined to one lymph node site-	[63, 64]
	Stage II	Confined to more than one lymph node site but on one side ofthe diaphragm.
	Stage III	Confined to lymphatic tissue or spleen but on both sides ofthe diaphragm.
	Stage IV	Bone marrow or liver involvement or extranodal sites withwidespread involvement.
Tumor staging used as a complement to the Ann Arbor stagingsystem for nasal NKTCL	T1	Confinement to the nasal cavity.	[65]
	T2	Extension to the maxillary antra, anterior ethmoid sinus orhard palate.
	T3	Extension to posterior ethmoid sinus, sphenoidal sinus,orbit, superior alveolar bone, cheeks, or superiorbuccinators space.
	T4	Involvement of the inferior alveolar bone, inferiorbuccinators space, infratemporal fossa, nasopharynx, orcranial fossa.

Abbreviations: NK natural-killer cells, NKTCLNK/T-cell Lymphoma, nasal type.
* Subscripts: A or B: absence (A) or presence (B) of constitutionalsymptoms; E: “extranodal” disease; X: largest tumor>10 cm large (“bulky disease”), or mediastinumwider than 1/3 of the chest on a chest X-ray; S: spleen involvement.NKTCL are usually extranodal lymphomas; thus, the subscript Eapplies to the vast majority of cases.

ISSN: 1750-1172