| Grade | Description | Histologic features |
| 0 | Normal | Scattered plasma cells in lamina propria; no lymphoid follicles |
| 1 | Chronic active gastritis | Small clusters of lymphocytes in lamina propria; no lymphoid follicles; no LELs |
| 2 | Chronic active gastritis with florid lymphoid follicle formation | Prominent lymphoid follicles with surrounding mantle zone and plasma cells; no LELs |
| 3 | Suspicious lymphoid infiltrate in lamina propria, probably reactive | Lymphoid follicles surrounded by small lymphocytes that infiltrate diffusely in lamina propria and occasionally into epithelium |
| 4 | Suspicious lymphoid infiltrate in lamina propria, probably lymphoma | Lymphoid follicles surrounded by CCL cells that infiltrate diffusely in lamina propria and into epithelium in small groups |
| 5 | Marginal zone lymphoma | Presence of dense diffuse infiltrate of CCL cells in lamina propria with prominent LELs |
