In gastric extranodal marginal zone lymphoma, the frequency of nodal involvement and its pattern varies depending whether there is a large cell component to the lymphoma and on the depth of invasion1
Frequency of nodal involvement:
|
|
cases with involved nodes |
proportion of nodes involved |
|
||||||||||||
|
pure MALToma |
2/13 |
2/408 (0.5%) |
|
||||||||||||
|
MALToma with a minor large B-cell lymphoma |
5/6 |
21/253 (8%) |
|
||||||||||||
|
large B-cell lymphoma with MALT lymphoma |
9/12 |
149/429 (35%) |
|
||||||||||||
|
pure large B-cell lymphoma |
6/6 |
27/223 (12%) |
|
||||||||||||
|
Overall |
22/27 |
199/1313 (15%) |
|
Pattern of nodal involvement:
|
|
most common pattern |
lymph nodes involved |
sinusoidal |
sinusoidal and subsinusoidal |
sinusoidal |
sinusoidal and follicular |
follicular |
sinusoidal and diffuse |
subsinusoidal and diffuse |
follicular and diffuse |
diffuse |
|
pure MALToma |
mainly sinusoidal / subsinusoidal |
2/409 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
|
MALToma with a minor large B-cell lymphoma |
mainly sinusoidal / subsinusoidal |
21/249 |
4 |
13 |
0 |
0 |
1 |
0 |
0 |
1 |
2 |
|
large B-cell lymphoma with MALT lymphoma |
mainly diffuse |
149/430 |
2 |
26 |
6 |
3 |
12 |
0 |
5 |
14 |
81 |
|
pure large B-cell lymphoma |
mainly follicular or diffuse |
27/225 |
1 |
2 |
2 |
1 |
6 |
2 |
2 |
4 |
7 |
|
Overall |
199/1313 |
7 |
42 |
8 |
4 |
19 |
2 |
7 |
19 |
91 |
Despite the frequency of colonisation of follicles within the primary MALToma, a follicular pattern is uncommon in the nodal metastases.
Differential diagnoses:
sinusoidal pattern: sinus histiocytosis. CD20 highlights the B-cells of sinusoidal involvement.
follicular pattern: follicular hyperplasia. Neoplastic follicles lack a mantle, tingible body macrophages and CD21-positive follicular dendritic cells and are CD10 negative.
References