Histopathology of iatrogenic injury in the colorectum

Medical interventions may cause histologic changes and injury to the colorectal mucosa. Many of these changes overlap with one another and with medical gastrointestinal disease, such as inflammatory bowel disease. This review focuses on common causes of iatrogenic injury and the histologic patterns seen on mucosal biopsies. Topics covered include: 1. Endoscopy-induced artefacts, including mucosal pseudolipomatosis, pneumatosis coli, crush and cautery artefacts, and disinfectant colitis; 2. Changes induced by surgery and other therapies, including diversion colitis, radiation colitis, and graft versus host disease; and 3. Changes induced by drugs and toxins, including melanosis coli, chemotherapy, non-steroidal-anti-inflammatory drugs, mycophenolate, kayexalate, and bowel preparations.