S6396 An Unusual Presentation of Gastric Diffuse Large B-Cell Lymphoma

Introduction: Lymphomas account for about 5% of gastric cancers, most commonly mucosa-associated lymphoid tissue (MALT) lymphoma and primary gastric diffuse large B-cell lymphoma (PG-DLBCL). While Helicobacter pylori (HP) is strongly linked to MALT lymphoma, its role in DLBCL remains less clear. PG-DLBCL arise de novo or from untreated MALT, and it most commonly presents in the sixth decade of life in males. We present a rare case of PG-DLBCL in a young woman with HP infection. Case Description/Methods: A 34-year-old woman from Turkey presented with months of worsening epigastric pain radiating to the right shoulder and rare vomiting. There were no constitutional symptoms. Her exam revealed epigastric tenderness, and pain resolved promptly with omeprazole. Labs noted mild iron deficiency anemia. Computed tomography (CT) abdomen showed focal hypoattenuating mucosal wall thickening of the gastric body prompting referral to gastroenterology. Esophagogastroduodenoscopy (EGD) revealed a large ulcerated and friable fungating mass in the gastric body and a smaller polypoid mass in the antrum with diffuse erosive gastropathy. Biopsies from both lesions were morphologically similar and consistent with PG-DLBCL (positive for CD20, PAX5, and BCL6). Additional biopsies showed gastric intestinal metaplasia, chronic inflammation, and HP infection. PET-CT staging showed localized disease to the stomach and perigastric lymph nodes (Stage II, Lugano classification). Her International Prognostic Index (IPI) score was 2, indicating low-intermediate risk. She was treated with quadruple therapy for HP eradication (HPE) and recommended to undergo 4-6 cycles of R-CHOP. Discussion: This case offers several clinical insights including the clinical importance of understanding HP prevalence and virulence factors. While the patient presented for care in the United States, she originates from Turkey, a highly endemic country where 1 nationally representative study found 82.5% of asymptomatic individuals screened with the C-Urea breath test were positive for HP. Additionally, Turkey has a higher prevalence of virulent genotypes (estimated 71% cagA-positive strains), which are known to increase the risk of gastric cancer. Finally, while emerging data suggests HPE alone may lead to remission in up to 66% of localized PG-DLBCL, the standard of care for treatment of extra-nodal DLBCL remains systemic chemoimmunotherapy, like R-CHOP in medically fit patients, with excellent prognosis (overall and progression free survival of >85%).