Colonic Marginal Zone B-Cell Lymphoma (MALT Lymphoma) in a Patient Negative for H. pylori: Case Report

Abstract

Introduction: 80-year-old female found to have 30-mm uT4 uN3 sigmoid Marginal Zone B-cell lymphoma during colonoscopy and subsequent EUS with negative H. pylori antigen testing and EGD tissue biopsy. Case Description:During routine colonoscopy a patient was found to have a large non-obstructing sigmoid mass 30-cm proximal to the anus (figure 1). Four days later, EUS examination revealed a 30-mm mass evading through the muscularis propria into the serosa (figure 2). The mass was suspicious for adenocarcinoma and staged via EUS as uT4 uN3 tumor. However, the pathology was positive for Marginal B-Cell Lymphoma. The patient was sent for H. pylori stool antigen testing, EGD examination and referred to colorectal surgery. EGD showed a non-bleeding gastric ulcer along with chronic gastritis. Multiple biopsies including that of duodenal bulb, antrum and gastro-esophageal junction showed normal mucosa negative for H. pylori. After 12 weeks of PPI therapy, repeat EGD showed resolution of the gastric ulcer. As the patient remained asymptomatic, no further treatment modalities were initially pursued. However, given the association between MALT lymphoma and H. pylori infection, the patient was empirically started on triple therapy and will have a repeat colonoscopy for further assessment of the mass at the completion of therapy. Discussion: MALT lymphomas are usually defined as low grade B-Cell lymphoma that can occur in variety of extranodal organs though the most common site is the stomach with the colon and rectum accounting for <10% of the cases. Colonic MALT lymphomas are usually an incidental finding on colonoscopic examination or coinciding with a GI bleed. Currently, a treatment consensus is lacking. There have been case reports in which patient negative for H. pylori have improved after eradication antibiotic therapy due to the elimination of an unknown luminal organism. Radiation, surgical resection, chemo and immunotherapy, and endoscopic removal of the colonic lesions have also been described as fairly successful treatment modalities without any evidence of recurrence. At present, prognosis of non-gastric MALT is usually poor with a 5-10-year survival rate with disseminated lymphoma being implicated as the cause of death 20-50% of the time. It is prudent that clinicians and researcher alike remain aware of non-gastric MALT lymphoma and their associated outcomes in pursuit of improving treatment algorithms for these tumors in the future.1630_A Figure 1. Non-obstructing sigmoid mass 30 cm proximal to the anus.1630_B Figure 2. The 30-mm sigmoid mass breaking through the muscularis propria into the serosa examined via EUS (Endoscopic Ultrasound)