P1714 - An Atypical Finding of Colonic Marginal Zone Lymphoma

Mohamed Elmasry, DO¹, Aleem A. Ali, MD¹, Lauren Stemboroski, DO^2
1University of Florida College of Medicine Jacksonville, Jacksonville, FL; ²University of Florida-Jacksonville, Jacksonville, FL

Introduction: Extranodal Marginal Zone Lymphoma (EMZL), also known as mucosa-associated lymphoid tissue (MALT) lymphoma, most commonly occurs in the gastrointestinal (GI) tract with the stomach being the most affected site followed by the small intestine. EMZL in the colon is a rare clinical entity that accounts for 2.5% of MALT lymphomas. We describe an unusual case of colonic EMZL diagnosed on two different biopsy sites during routine surveillance colonoscopy.

Case Description/Methods: A 76-year-old female with a prior history of treated ductal carcinoma of the breast presented for a routine surveillance colonoscopy. Her last colonoscopy was three years prior which resulted in the removal of two pre-cancerous polyps. This colonoscopy revealed abnormal, nodular- appearing mucosa in the cecum and a 6 mm sessile polyp in the rectum. The abnormal mucosa was biopsied, and the polyp was retrieved via cold snare. Pathology of the specimens revealed atypical lymphoid aggregates that were predominantly small B lymphocytes with positive CD-20, Bcl-2, and negative CD 3, cyclin D1, Bcl-6. These findings were consistent with low grade EMZL. A bone marrow aspirate with smears and flow cytometry confirmed a diagnosis of EMZL. Computed tomography of chest, abdomen, and pelvis showed enlarged mediastinal lymph nodes with prominent lymph nodes within the retroperitoneal and superior abdominal areas. The patient was then started on Rituximab.

Discussion: MALT lymphoma of the colon is a rare clinical entity and the literature on colonic MALT is limited to a few case reports. Colonic MALT lymphoma is typically localized, and most commonly detected on histology of polyps retrieved during colonoscopy. Unique to this case, there were two separate biopsied areas of the colon with varying endoscopic appearance that returned showing lymphoma. The case highlights a rare and atypical presentation of colonic EMZL in an asymptomatic patient incidentally detected during routine surveillance colonoscopy. There are currently no guidelines in the literature due to a limited number of reported cases. Although colonic EMZL is rare, it should be considered in the differential diagnosis for colonic polyps and abnormal mucosa found on colonoscopy. With the advent of high-definition endoscopy and in the experienced hands of an endoscopist, thorough examination of the colon on withdrawal is paramount for detection of these colonic MALT lesions.



Disclosures:


Mohamed Elmasry, DO¹, Aleem A. Ali, MD¹, Lauren Stemboroski, DO². P1714 - An Atypical Finding of Colonic Marginal Zone Lymphoma, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.