Diverticular colitis with progression to ulcerative colitis after sigmoidectomy

Diverticular colitis is chronic inflammation of the colon where diverticula are present. The endoscopic and histopathological findings of this disease are sometimes similar to those of ulcerative colitis, and several reports describe cases of diverticular colitis that progressed to typical ulcerative colitis. A 77-year-old woman with intramesenteric penetration of the sigmoid diverticulum underwent low anterior resection. One month later, the patient experienced anastomotic leakage, and transverse colostomy was performed. Six months after the colostomy, the patient returned to the hospital with complaints of bloody discharge from the rectum and stoma. Colonoscopy revealed newly developed loss of vascular pattern and a granular appearance of the mucosa in the rectum that had not been present at prior examinations. She was diagnosed with ulcerative colitis, which developed after colectomy, and treated with mesalazine and high-dose prednisolone, but the clinical and endoscopic response was poor. Finally, the patient underwent total proctocolectomy and ileal pouch anal anastomosis with diverting ileostomy. As a few reports have described, diverticular colitis can progress to typical ulcerative colitis after surgery in some cases, suggesting a possible pathogenic similarity between the two diseases and association between colorectal surgery and disease progression.