Duodenal bulb biopsy in the diagnostic work-up of coeliac disease.

Coeliac disease (CD) is an autoimmune enteropathy which can present with patchy mucosal lesions. The aim of the present study is to investigate the significance of duodenal bulb biopsy in the diagnostic work-up of CD in both pediatric and adult patients, and to highlight the key points for pathologists. D1 (duodenal bulb) and D2 (distal duodenum) biopsies of 153 newly diagnosed serology-positive CD patients were evaluated for villous/crypt ratio and intraepithelial lymphocyte (IEL) counts on CD3-stained slides and were classified according to Marsh. Mucosal pathology was patchy in 15% (13% only D1 and 2% only D2) of patients, and 85% of patients had diffuse mucosal pathology involving both D1 and D2 biopsies which showed concordant histology in 60% and discordant in 25% of the cases. Though majority of the patients (75%) with only D1 involvement were pediatric cases, no significant difference was found between pediatric and adult patients when all cases were considered (17 vs 14%). Our results clearly indicate that without D1 sampling, diagnosis of CD would have been missed in a significant number of cases (13%), thereby highlighting the importance of taking duodenal biopsies from multiple sites in the diagnostic work-up of CD. We, therefore, conclude that every biopsy piece from both D1 and D2 should be carefully evaluated for the whole spectrum of mucosal changes caused by gluten ingestion and classified using a scheme based on Marsh to allow recognition of mild lesions.