Endoscopic biopsy samples of naïve "colitides" patients: role of basal plasmacytosis

Background: Although it is usually not difficult to diagnose inflammatory bowel disease (IBD) on surgical resection specimens, difficulties sometimes arise in differentiating these entities from other forms of colitis on endoscopic biopsy specimens. Basal plasmacytosis is considered as an early feature of IBD colitis, but it is rare in non-IBD colitides. Aims: We assessed the value of basal plasmacytosis as an individual variable in untreated patients with colitis. Patients and methods: Archival slides of patients with untreated colitis (66 IBD and 49 non-IBD) and 20 controls with complete (from the terminal ileum to the rectum) endoscopic biopsy sampling were evaluated blindly for the presence of basal plasmacytosis and a possible association with the presence of eosinophils in the same anatomical location. Results: Overall, basal plasmacytosis was present in at least one anatomical segment in 58% of cases, and it was always present in patients with IBD, whereas it was sparsely found (9%) in patients with other colitides and in controls. Basal plasmacytosis in three or more segments had more than 80% probability for a patient to be classified as IBD, with the segmental distribution being different between ulcerative colitis and Crohn's disease. Additionally, basal plasmacytosis was always accompanied by eosinophils intermingled with plasma cells in the same anatomical position. Conclusion: As an individual feature, basal plasmacytosis (accompanied by eosinophils) is a strong feature suggesting IBD, particularly when present in three or more colonic segments. This fact may be useful in the evaluation of endoscopic biopsies from patients with "colitis". (C) 2014 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.