Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Presenting with Both Gastric and Small Bowel Involvement: A Case Report

Abstract

MALT Lymphoma is a subtype of mature B-cell lymphoma that comprises 5% of all non-Hodgkin lymphomas and 50% of all gastric lymphomas frequently associated with H. pylori infection. Symptoms are non-specific. Although MALT lymphoma is one of the more common type of gastric lymphomas, small bowel involvement is rare. A 52 year old man from Antigua with a medical history of remote peptic ulcer disease (unknown H. pylori status) presented to the emergency department with complaint of fatigue and malaise after a recent three day history of resolved non-bloody diarrhea. He reported anorexia and a 20-lbs unintentional weight loss over the past year. Physical examination was pertinent for cachexia with temporal wasting, soft but distended abdomen with shifting dullness and no organomegaly. No edema or any skin rashes/lesions observed. Laboratory investigations showed mild normocytic anemia, low iron with normal TIBC/ferritin, elevated ESR/CRP, and normal stool studies. Chest x-ray showed moderate left-sided effusion and pleural fluid studies revealed exudative type effusion with many lymphoid cells. Abdomen CT scan showed diffuse circumferential wall thickening of the small bowel with bulky mesenteric and retroperitoneal lymphadenopathy, and moderate ascites. Tumor markers for CEA and Ca19.9 were negative but Ca125 was elevated. EGD showed prominent gastric folds, normal-appearing duodenum, and erythematous antral mucosa. Biopsy showed chronic active H. pylori gastritis and MALT lymphoma. Further, colonoscopy was done and showed a prolapsing, edematous terminal ileum, and upon biopsy, also revealed MALT lymphoma. Further, IR-guided retroperitoneal biopsy revealed multiple small to medium size lymphoid cells with irregular contours that were CD20, PAX-5, CD43 and BCL2 positive with 10-20% proliferation by Ki67 staining consistent with MALT lymphoma. PET CT scan was done and showed diffuse mediastinal and abdominal hypermetabolic lymphadenopathy. The patient was started on triple therapy for H. Pylori and R-CHOP (rituximab, cyclophosphamide, doxorubicin, oncovin, and prednisone) chemotherapy. This case illustrates a rare presentation of MALT lymphoma involving the stomach and small bowel. The elevated Ca125 is consistent with its presentation. The relationship between these atypical presentations and more typical gastric presentations remains unclear. More research is needed to determine whether they remain a distinct subset or an unrelated condition.