Pathologic features of the gastric mucosa adjacent to primary MALT-lymphomas.

The frequency of reported cases of primary gastric mucosa-associated lymphoid tissue (MALT)-lymphoma is increasing worldwide. Helicobacter pylori plays a preponderant role in its pathogenesis. Gastric MALT-lymphoma arises from nonrecirculating centrocytelike cells located at the periphery of reactive lymphoid follicles, which are common in patients infected with this microorganism. Histopathologic features other than lymphoid follicles have not been well described. In this study the authors describe the morphologic changes in the gastric mucosa adjacent to MALT-lymphomas. From the files of the departments of pathology at the Instituto Nacional de Cancerologia and the Instituto Nacional de la Nutricion in Mexico City, primary gastric MALT-lymphomas were retrieved. Patients with hematoxylin-eosin-stained histologic sections, including the overt neoplasia and the neighboring gastric mucosa, were selected. Lymphoid follicles as well as intestinal metaplasia, atrophy, and eosinophils were evaluated as present or absent and graded as proposed by the Updated Sydney System for gastritis. Fifty-one patients were eligible for analysis. There were 35 low-grade and 16 high-grade primary MALT-lymphomas. Forty-seven patients (92.6%) showed reactive lymphoid follicles in the neighboring mucosa, 32 patients (69.5%) had intestinal metaplasia, and 26 patients (54.1%) demonstrated atrophy. In 41 patients (73.8%) there was an increased number of eosinophils. Our findings suggest that lymphoid follicles, intestinal metaplasia, atrophy, and eosinophils in an endoscopic biopsy are markers of both gastric lymphoma and carcinoma.