Clinicopathologic features of surgically resected primary gastric lymphoma

Table 1 Musshoff’s modified Ann-Arbor stage

Stage	Definition
Ie	Involvement of a single extralymphatic organ or site1
Ie1	Involvement of mucosa or submucosa
Ie2	Involvement of more than submucosa
IIe	Involvement of two or more lymph node regions on the same side of the diaphragm
	with localized involvement of an extralymphatic organ and site1,2
IIe1	Involvement of regional lymph nodes
IIe2	Involvement of other lymph nodes beyond regional area
IIIe	Localized involvement of a single extralymphatic organ or site with involvement of lymph node regions on
	both sides of the diaphragm (IIIe) or involvement of the spleen (IIIs) or both (IIIe+s)1,2
IVe	Involvement of extranodal site(s) beyond that designated as “e” more than one extranodal
	deposit at any location, any involvement of liver or bone marrow1,2
E	localized, solitary involvement of extralymphatic tissue, excluding liver and bone marrow
1	Direct spread of a lymphoma into adjacent tissues or organs does not influence stage. Multifocal involvement of a single extralymphatic organ is classified as stage IE and not stage IV. Involvement of two or more segments of the gastrointestinal tract, isolated and not in continuity, is classified as stage IV (disseminated involvement of one or more extralymphatic organs).
2	The definitions of regional lymph nodes for individual sites of extranodal lymphomas are identical to the definitions of regional lymph nodes for individual sites of gastrointestinal carcinomas. For example, the regional lymph nodes for a primary gastric lymphoma are the perigastric nodes along the lesser and greater curvatures and the nodes located along the left gastric, common hepatic, splenic, and celiac arteries.