A 5-year clinicopathological study on microscopic colitis at a Malaysian tertiary hospital.

INTRODUCTION: Microscopic colitis (MC) is a well-recognised cause of chronic diarrhoea in Western countries. It is classically associated with normal endoscopic findings and a higher prevalence among patients with autoimmune disease. Local information regarding this disease remains scarce. We identified patients diagnosed with MC over a five-year period, and then proceeded to analyse the clinical characteristics of these cases. MATERIALS AND METHODS: A retrospective study was conducted by identifying all histologically confirmed colitis cases diagnosed at Hospital Universiti Sains Malaysia from January 2015 until December 2019. Clinicodemographic data was retrieved from case notes of patients. RESULTS: Of the 299 cases with histological colitis, 23 (7.7%) were initially identified as MC. Two cases had incomplete data, while two others were excluded as the diagnoses were revised to inflammatory bowel disease. An incidence of 14 MC cases/1000 case-year was obtained using the 21 MC cases seen within the five-year period. MC subtypes for the 19 analysed cases i.e., lymphocytic colitis and collagenous colitis accounted for 13 (68.4%) and 6 (31.6%) cases, respectively. Eleven patients (57.9%) were females (M:F ratio 1:1.5) with a median age of 51 years. Only nine (47.3%) presented with diarrhoea; one subject (5.4%) had an autoimmune condition (Hashimoto thyroiditis). Normal endoscopic findings were found in 89.5% of patients. CONCLUSION: Approximately half of the subjects in our study who had histologically confirmed MC did not present with diarrhoea. Adequate biopsy samples despite normal colonoscopy findings are important in order to not miss the diagnosis of MC.