P220 Total colonoscopy is needed to establish the diagnosis of lymphocytic colitis: results from a single-centre retrospective cohort
C. Csóka1, P. Miheller1, A. A. Csontos1, T. Micsik2, K. Hagymási1, L. Herszényi1, M. Juhász1, D. Lippai1, E. Mihály1, K. Müllner1, A. M. Németh1, Z. Péter1, F. Sipos1, H. Székely1, Z. Tulassay1, G. Valcz3, A. V. Patai*1
1Semmelweis University, Second Department of Medicine, Budapest, Hungary, 2Semmelweis University, 1st Department of Pathology and Experimental Cancer Research, Budapest, Hungary, 3Hungarian Academy of Sciences, Molecular Molecular Medicine Research Group, Budapest, Hungary
Microscopic colitis (MC) is a subtype of inflammatory bowel diseases. Although subtle mucosal changes might be present, these endoscopic alterations are specific and difficult to detect with conventional white light endoscopy. Histopathologic diagnosis is a requisite in all cases. Whether MC expands the entire colonic mucosa or only a segment of the colon is not yet known. In the literature, it is debated whether a single left-sided biopsy is sufficient to diagnose MC. We aimed to examine the importance of biopsy location in the establishment of the diagnosis of MC.
All cases of MC diagnosed at colonoscopy between January 2008 and December 2014 were retrieved at the First Department of Pathology and retrospectively reviewed. The diagnostic criteria for lymphocytic colitis (LC) were ≥ 20 intraepithelial lymphocytes per 100 epithelial cells, and for collagenous colitis (CC), a collagenous layer of ≥ 10 μm. Number and locations of biopsies were analysed.
In total, 75 cases of MC, 10 cases with CC and 65 with LC, were identified during the study period. Samples were taken in 45 cases from the right colon, in 55 cases from the left colon, and in 34 cases from both sides. The diagnosis of LC would have been missed in 23% (8/34) of cases, if only left-sided biopsies had been taken, whereas all cases (100%) of CC were diagnosed with distal colonic biopsies alone.
LC seems to be more common than CC in our cohort, but this might be due to histopathologic under-diagnosis. Contrary to others, we found that total colonoscopy is necessary to diagnose all cases of LC, as every fourth LC cases would have been missed, if only sigmoideoscopy had been performed.