Background:
Extranodal marginal zone B-cell lymphoma mucosa-associated lymphoid tissue (MALT lymphoma) most frequently affects the stomach and is linked to Helicobacter pylori infection, which promotes chronic antigenic stimulation and lymphoid proliferation (1,2). Colon involvement is rare, and synchronous gastric and colonic MALT is extremely rare, with less than 20 cases reported worldwide. Because clinical manifestations mimic inflammatory or benign colonic disease, diagnosis may be delayed (3-4). The few documented cases present make the underlying mechanisms unclear, and the diagnostic approach remains challenging (3-4). We report a case of synchronous gastric and sigmoid colon MALT lymphoma associated with H. pylori infection in a 50-year-old man being treated with eradication therapy, periodic imaging, and endoscopic surveillance.
Case Description:
A 50-year-old man with no significant past medical history presented with several months of intermittent abdominal pain, bloating, constipation, and mucus discharge per rectum. Clinical examination revealed small internal haemorrhoids and mild left lower-quadrant tenderness. Esophagogastroduodenoscopy (OGD) demonstrated a crater-like ulcer in the mid-gastric body with surrounding irregular mucosa. Histopathology revealed a low-grade B-cell lymphoma consistent with gastric MALT type. Given persistent lower abdominal discomfort, a colonoscopy was performed, revealing a 40mm hemi-circumferential ulcerated and oedematous lesion in the sigmoid colon. Biopsies revealed dense lymphoid infiltrates with features of marginal zone lymphoma.
Outcome:
The patient received two courses of H. pylori eradication therapy. Follow-up upper endoscopy showed marked regression of the gastric lesion into a fibrotic scar. Biopsies from this area, however, continued to demonstrate residual morphological and immunophenotypic features consistent with MALT lymphoma, while the lesion appeared endoscopically inactive. The patient remained asymptomatic, and imaging was stable, leading to a “watch-and-wait” strategy, including periodic imaging and joint endoscopic surveillance by gastroenterology and haematology services.
Conclusion:
Synchronous gastric and colonic MALT lymphoma is an exceedingly rare presentation of extranodal marginal zone lymphoma (5). This case highlights the diagnostic importance of correlating imaging, endoscopic, and histopathologic findings in patients with nonspecific gastrointestinal symptoms, as is the therapeutic impact of H. pylori eradication. A conservative approach with histological reassessment and close follow-ups is the most reasonable for localized, indolent disease.