Table 2

Lugano system for staging of lymphomas (79)

Stage of disease	Traits of stage
Stage I	Tumour confined to the GI tract, single primary site or multiple noncontinuous lesions
Stage I₁	Tumour does not exceed the mucosa and submucosa
Stage I₂	Tumour infiltrates into muscularis propria and/or subserosa and/or serosa
Stage II	Tumour extends into abdomen from primary GI site
Stage II₁	Local lymph node involvement^*
Stage II₂	Distant lymph node involvement^†
Stage IIE	Penetration of serosa with involvement of adjacent organs/tissues^‡
Stage IV	Disseminated disease with involvement of extranodal sites, or primary GI lesion plus supradiaphragmatic nodal involvement

GI = gastrointestinal.
↵* Perigastric nodes are considered regional for gastric lymphoma.
↵† Mesenteric nodes are considered distant for gastric lymphoma.
↵‡ The actual site of involvement must be enumerated, e.g., IIE_(pancreas). In cases where there is both nodal and extranodal involvement beyond that of the primary site, this is denoted using both the final E and subscript, e.g., IIE1_(pancreas).