Gastric Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue and Signet Ring Cell Carcinoma, Synchronous Collision Tumour of the Stomach: A Case Report

OBJECTIVE: To report a rare case of synchronous marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) signet ring cell carcinoma occurring as a collision tumour in the stomach. CLINICAL PRESENTATION AND INTERVENTION: A 53-year-old man was diagnosed initially with signet ring cell carcinoma of the stomach. The microscopy of the subsequent total gastrectomy revealed a collision tumour of MALT lymphoma and signet ring cell carcinoma associated with Helicobacter pylori gastritis. CONCLUSION: This case highlighted the importance of a careful evaluation of the accompanying lymphoid population in the biopsy samples of gastric adenocarcinoma and underlined the need for multiple endoscopic biopsies to detect these rare synchronous tumours.