ORAL COMMUNICATION | When a functional disorder is not functional and an ileitis is not ileitis: a case of gastrointestinal MALT lymphoma

Introduction. A 50-year-old woman with a past diagnosis of nervous gastritis presented with a 10-day history of epigastric pain and appetite loss, initially attributed to emotional stress. She later developed a fever and occasional diarrhea.

Description. Initial blood tests were unremarkable, except for mildly elevated C-reactive protein (3 mg/dL). Stool studies excluded infection but revealed markedly increased fecal calprotectin (>1000 µg/g). Abdominal ultrasound and CT imaging demonstrated ileitis. Suspecting inflammatory bowel disease, endoscopy with biopsies from the stomach, colon, and ileum was performed. Histology revealed lymphoepithelial lesions with small- to medium-sized lymphocytes across all sites. Immunohistochemistry confirmed extranodal marginal zone B-cell lymphoma (MALT), positive for CD20 and Bcl-2, with a Ki-67 index of 2%. Helicobacter pylori was detected in gastric biopsies. The patient started eradication therapy with proton pump inhibitors and combined antibiotics. She was also referred to hematology for further management. She achieved complete remission without the need to start chemotherapy.

Conclusions. H. pylori-positive MALT lymphomas are indolent neoplasms driven by chronic antigenic stimulation and often regress after successful eradication, as in this patient. Additional treatments are reserved for refractory or advanced disease. Although initially appearing trivial, this case underscores how thorough diagnostic evaluation is essential, even in mild presentations, to ensure timely identification of clinically relevant conditions.