Ulcerative gastric MALT lymphoma with marked eosinophilic infiltration: a case report.

Primary gastric lymphoma (PGL) is a rare form of non-Hodgkin lymphoma, mainly comprising mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBCL). The clinical significance of marked eosinophilic infiltration in gastric MALT lymphoma remains unclear. We report a 50-year-old male with a two-year history of recurrent abdominal pain. Endoscopy revealed a large ulcerative lesion in the middle of the greater curvature of the gastric corpus. Histopathology showed Helicobacter pylori (H. pylori) infection with marked eosinophilic infiltration, leading to initial diagnostic uncertainty. The patient underwent H. pylori eradication therapy, but persistent symptoms required further evaluation with magnifying endoscopy and repeat biopsy. Immunohistochemistry confirmed gastric MALT lymphoma. After a second course of eradication therapy, the lesion size decreased, mucosal healing was observed, and symptoms resolved. This case highlights that gastric MALT lymphoma should be considered in patients with ulcerative lesions accompanied by prominent eosinophilic infiltration, and emphasizes the importance of combined endoscopic and histopathological evaluation for accurate diagnosis.