The sine qua non of the histologic diagnosis of a gastric pseudolymphoma is:

C. A germinal center in the gastric lesion.

DISCUSSION: Pseudolymphoma represents approximately 10% of all gastric lymphomas. These are benign conditions involving mostly the mucosa without evidence of nodal disease and without extragastric extension. The sine qua non for the diagnosis is a germinal center within the gastric lesion. These are premalignant lesions but can be cured completely with conservative resection.