A196 MORE MICROSCOPIC THAN WAS THOUGHT: A RARE CASE OF ISOLATED LYMPHOCYTIC ILEITIS WITHOUT MICROSCOPIC COLITIS. (4th March 2021)

• Record Type: Journal Article
• Authors: Singh, K S; Yanofsky, R; Haegert, D; Gao, Z; Bessissow, T
• Is Part Of: Journal of the Canadian Association of Gastroenterology. Volume 4(2021)Supplement 1
• Page Start: 219
• Page End: 220
• Publication Date: 2021-03-04
• Subjects: Gastroenterology -- Periodicals; 616.33005
• DOI: 10.1093/jcag/gwab002.194
• Languages: English
• ISSNs: 2515-2084

Abstract

Abstract: Background: Microscopic colitis (MC) is a chronic inflammatory disease of the colon characterized by lymphocytic infiltration with (collagenous colitis) or without (lymphocytic colitis) the expansion of collagen fibres, and the normal macroscopic appearance of the mucosa on ileocolonoscopy. Recent studies have shown that the ileum may be involved in MC, occurring concurrently with colonic disease, however there is sparse literature on isolated lymphocytic ileitis without colitis. Aims: We describe the case of isolated small bowel lymphocytosis without evidence of lymphocytic colitis to highlight the utility of random biopsies of the terminal ileum in cases where microscopic colitis is a diagnostic consideration. Methods: A 70-year-old female known for cutaneous mastocytosis presented with six weeks of abdominal pain, non-bloody diarrhea, intolerance to oral intake and significant weight loss. Computed-tomography showed evidence of possible mesenteric panniculitis. Colonoscopy revealed a normal colon and normal-appearing mucosa of the terminal ileum. Random mucosal biopsies were taken to assess for microscopic colitis, with terminal ileal biopsies revealing significant lymphocytic infiltration consistent with lymphocytic ileitis. Biopsies throughout the colon revealed normal colonic mucosa without evidence of concurrent microscopic colitis. Gastroscopy was macroscopically unremarkable and random biopsies in the stomach and duodenum were negative for Helicobacter pylori and lymphocytosis. Immunostaining of the gastric, duodenal, terminal ileal and colonic biopsy specimens were negative for CD25, CD117 and tryptase, indicating the absence of gastrointestinal mastocytosis. Results: The patient was diagnosed with lymphocytic ileitis and given the known response of MC to budesonide, she was treated with eight weeks of budesonide with clinical improvement leading to remission of her symptoms. Conclusions: This case illustrates a rare incidence of isolated ileal microscopic ileitis without colitis that responded well to standard MC treatment, thereby underscoring the utility of random biopsies in the terminal ileum and throughout the colon when microscopic colitis is on the differential diagnosis. Funding Agencies: None