Tocilizumab-induced mucosal injury in the terminal ileum mimicking intestinal Behçet’s disease: A case report

Abstract

Rationale: Tocilizumab, a humanized anti-interleukin-6 (IL-6) receptor monoclonal antibody, is used for the treatment of adultonset Still disease (AOSD). Despite its efficacy in many clinical situations, concerns have been raised regarding intestinal mucosal injury in patients receiving tocilizumab.Patient concerns: A 64-year-old woman with a history of AOSD was admitted to our hospital with hematochezia. She had AOSD for 15 years and underwent treatment with biweekly tocilizumab 9 months prior to admission. Colonoscopy revealed a large punched-out ulcer in the terminal ileum. On pathological evaluation, nonspecific enteritis with lymphocytes and eosinophils were seen. Based on the location and shape of the lesion, we suspected intestinal Behçet's disease. However, the ulcer reduced in size over time by discontinuation of tocilizumab without additional drug treatment, indicating that it was a drug-induced ulcer.