An Aggressive MALT Lymphoma Despite Negative Helicobacter pylori Testing

Abstract

Purpose: MALT lymphoma is a form of non-Hodgkin B cell lymphoma (NHL) involving the mucosa-associated lymphoid tissue (MALT); however, the occurrence of Helicobacter pylori-negative lymphoma of the stomach—a primary gastric lymphoma, is not very common. Methods: We report a case of a 49-year-old Hispanic female with complaints of intermittent gastric pain, nausea and occasional vomiting for 2 years. The patient stated her pain was dull and went away with food and admitted to weight loss. She denied any significant past medical history or any familial gastrointestinal issues. Her lab values were within normal limits, except for mild anemia. Her physical exam was notable for epigastric tenderness. Subsequently, the patient was scheduled for upper endoscopy which demonstrated superficial ulceration, limited distensibility and rigidity. Extensive biopsies of the antrum and proximal stomach revealed necrotic debris with acute leucocytic exudation and extranodal marginal zone B cell lymphoma. Giemsa staining and serology for H. pylori was negative. The patient was then empirically started on triple antibiotic therapy (Amox/clav/PPI) for H. pylori eradication, and scheduled for endoscopic ultrasound (EUS). The EUS demonstrated excellent 5 layer echopattern throughout the stomach. The MALT lymphoma appeared to be confined to the superficial antral mucosa without peri gastric lymph node involvement. The patient underwent repeat endoscopy with multiple biopsies 4 weeks later which showed histologic persistence of MALT lymphoma. She was therefore referred to an oncologist for systemic chemotherapy. Results: Presently, 12 clinical studies with almost 400 patients and case reports have shown that a cure of H. pylori infection is associated with complete remission in approximately 80% of patients with low-grade MALT lymphoma in an early clinical stage. However, what can be done if the patient is found to be H. pylori negative? Rates of about 7-15% of H. pylori-negative gastric MALT lymphoma patients have been reported. The reason for the occurrence of a maltoma without the evidence of H. pylori is unknown. Perhaps multiple etiological factors are at fault for the pathogenesis of MALT lymphoma. Conclusion: Eradication strategies may not entirely preclude the risk for neoplastic transformation. H. pylori negative associated MALT may indeed represent a different clinical entity with more aggressive characteristics. Though rates are low, they remain significant. Despite directed HP treatment, our patient demonstrated persistent malignacy and ultimately needed systemic chemotherapy.