2519 A Rare Case of Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Involving Duodenum

Abstract

INTRODUCTION: Primary small bowel lymphomas account for only 8-9% primary gastrointestinal malignancies and mostly represent extra nodal B- or T-cell origin. Immunoproliferative small bowel disease (IPSID) is a common small bowel extra nodal primary lymphoma. Associated Lymphoid Tissue B cell lymphoma (MALT lymphoma) is a common primary gastric lymphoma. However, it is very rare to find MALT lymphoma in small bowel especially in duodenum. We report a unique case of MALT lymphoma involving duodenal bulb. CASE DESCRIPTION/METHODS: A 58-Yr-Old African American female, with history of type II diabetes, Hypertension, Osteoarthritis, and chronic GERD with symptom control on once a day low dose omeprazole was referred for evaluation of epigastric discomfort, bloating, and nausea for 2 months. Abdominal examination normal. Labs showed normal CBC with differential, and CMP. An upper endoscopy showed mild patchy erythema in stomach and a localized, raised, and nodular area about 4-5 cm in the duodenal bulb. Biopsies from stomach showed Helicobacter pylori chronic active gastritis. Biopsies from duodenum showed homogenous population of lymphoid cells with moderate amounts of clear cytoplasm expanding the lamina propria. Molecular studies showed positive B-cell Gene Rearrangement with positive Framework 1, 2, and 3. Immunohistochemical staining was positive for CD20, bcl2, and kappa; and negative for CD3, CD5, CD10, bcl6, CD43, Cyclin D1 and lamda. The pathology findings confirmed Margina zone lymphoma of Mucosa Associated Lymphoid Tissue (MALT lymphoma). Colonoscopy was normal except few diverticula. A CT scan of abdomen, pelvis, and chest did not show any other masses except prominent lymph nodes at the gastrohepatic ligament and duodenum. She is treated with antibiotic therapy for H pylori gastritis, and referred to oncology for further management. DISCUSSION: MALT lymphomas of stomach usually occur in females and can be associated with Helicobacter pylori infection. They are usually low grade lymphomas and localized to gastrointestinal epithelium. Clinical features, imaging, or endoscopy findings are not specific. Immunohistochemical staining shows positive for B cell phenotype markers like CD20, Bcl-2, and negative for CD 23, CD 10, and CD 5. Usually, they present with non-specific symptoms like epigastric pain, nausea, vomiting, early satiety, though can present with obstruction when the tumor is too large. Treatment of associated H pylori infection may help though chemoradiotherapy may be needed rarely.