RT Journal Article SR Electronic T1 Gastrointestinal lymphoma: the new mimic JF BMJ Open Gastroenterology JO BMJ Open Gastro FD BMJ Publishing Group Ltd SP e000320 DO 10.1136/bmjgast-2019-000320 VO 6 IS 1 A1 Shirwaikar Thomas, Anusha A1 Schwartz, Mary A1 Quigley, Eamonn YR 2019 UL http://bmjopengastro.bmj.com//content/6/1/e000320.abstract AB Background Gastrointestinal (GI) lymphomas comprise a group of distinct clinicopathological entities of B- or T- cell type, with primary gastrointestinal Hodgkin lymphoma being extremely uncommon. The GI tract is the predominant site of extranodal non-Hodgkin lymphoma accounting for 30–40% of all extranodal lymphomas. In the Western world, the stomach is the most commonly involved site followed by the small bowel. Several chronic inflammatory and immune-mediated disorders which predispose to accelerated cell turnover may lead to the malignant transformation of gut lymphocytes and ultimately manifest as GI lymphoma. The challenge for the clinical gastroenterologist is that these tumors may have varied presentations, ranging from nonspecific symptoms such as dyspepsia or bloating to abdominal pain, nausea, vomiting, GI bleeding, diarrhea, weight loss or bowel obstruction.Objective We illustrate the range of presentations of GI lymphoma with examples based on consecutive cases evaluated at our institution over a 6-month period. These cases demonstrate how appropriately directed endoscopic evaluation with biopsies has the potential to provide a definitive diagnosis and allow the patient to proceed to definitive therapy.Conclusions The GI tract is the most commonly involved site for extranodal lymphoma with the stomach being most frequently involved organ.Chronic Helicobacter pylori infection, celiac disease, inflammatory bowel disease and autoimmune disorders may predispose to GI lymphoma. This heterogenous group of diseases has varied presentations that may mimic several other GI clinico-pathologic entities. GI lymphomas may be diagnosed with appropriately directed endoscopic evaluation coupled with generous tissue sampling and expert pathologic assessment. Management may range from antibiotic therapy, in the case of Helicobacter pylori-associated gastric MALT lymphoma, to chemotherapy with or without radiation and, in rare instances, surgery. There are presently no guidelines to direct endoscopic surveillance of GI lymphomas following treatment.