S4420 Primary Esophageal Mucosa-Associated Lymphoid Tissue Lymphoma Masquerading as a Benign Tumor

Introduction: Primary gastrointestinal lymphomas represent only 10–15% of all non-Hodgkin lymphomas, with esophageal involvement being extremely rare—accounting for less than 1% of gastrointestinal lymphomas and only 0.2% of extra-nodal non-Hodgkin lymphomas. Most esophageal cases arise from direct extension of adjacent disease, while primary esophageal lymphomas are exceptionally rare. Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare but recognized variant. Its pathogenesis in the esophagus remains poorly understood, and clinical presentations are often nonspecific, hindering timely diagnosis. We present a rare case of primary esophageal malt lymphoma. Case Description/Methods: A 53-year-old man underwent a screening cardiac computed tomography due to a strong family history of coronary artery disease. A filling defect in the distal esophagus was incidentally identified. Retrospective review of imaging from 3 years prior showed a similar but smaller lesion. The patient was asymptomatic. Esophagogastroduodenoscopy revealed a 3 × 1 cm submucosal lesion in the distal esophagus. Endoscopic ultrasound identified a subepithelial nodule, 32–38 cm from the incisors causing luminal narrowing. The lesion appeared predominantly anechoic to slightly hypoechoic, originating from the submucosa. Esophagogram showed a polypoid mass without high-grade obstruction. Fine-needle biopsy was deferred due to concern for possible duplication cyst. Magnetic resonance imaging suggested a solid lesion, possibly leiomyoma, and chest computed tomography confirmed interval growth of a distal esophageal soft tissue mass. The patient underwent a robotic-assisted resection of the periesophageal nodule and mass. Histopathology confirmed extra-nodal marginal zone lymphoma (MALT lymphoma) of the esophagus. Positron emission tomography scan revealed moderate metabolic activity in the esophageal mass and widespread nodal involvement in the neck, thorax, abdomen, and inguinal regions consistent with stage IV disease. The patient was subsequently referred to hematology and initiated on a 6-week course of Rituximab therapy, with plans for ongoing response assessment. Discussion: This case illustrates a rare presentation of primary esophageal MALT lymphoma discovered incidentally in an asymptomatic patient. It underscores the diagnostic complexity of submucosal esophageal lesions and the importance of considering lymphoma in the differential. Early identification and appropriate staging are critical to guide timely therapy and improve outcomes.