Histological changes associated with the use of intravenous cyclosporin in the treatment of severe ulcerative colitis may mimic dysplasia

Background  During six years experience of intravenous cyclosporin (iv Cy) for severe ulcerative colitis we have noted that changes of villous architecture and epithelial regeneration occur even when the disease fails to enter clinical remission and colectomy is required. Objective  To describe the histological changes in patients who received iv Cy and steroids compared with those treated with iv steroids alone. Patients and methods  Two groups of histological sections were reviewed. The first group was of 23 colectomy specimens from patients who had been treated with iv Cy and steroids. For 11 patients pre‐Cy histological sections were available. The second group was of 10 colectomy specimens from patients who had received iv steroids alone. Biopsies were scored for their histological disease activity (HDAI), villous architecture and epithelial regeneration. The HDAI assesses the degree of acute and chronic inflammation. Results  The post‐Cy group had higher median scores for villous architecture and epithelial regeneration compared to the pre‐Cy and poststeroid groups. For the patients where both pre‐ and post‐Cy histological sections were available 63% increased their villous score post‐Cy and 82% increased their epithelial regeneration score post‐Cy. Conclusion  Although villous transformation and epithelial regeneration may be seen in UC they are more frequent and more severe in those patients who received iv Cy and iv steroids, compared to controls who received iv steroids alone. These histological changes may mimic dysplasia. Increased awareness of this potential mimic of dysplasia is crucial for patient management.