We describ the case of a 73-year-old man with diverticular colitis, a newly established disorder of chronic segmental colitis associated with diverticulosis. At the age of 63 years, the patient was admitted to our hospital for a hemorrhagic gastric ulcer. At the age of 67 years, he was diagnosed with anemia. A colonoscopy revealed segmental inflammation of the ascending colon. Histopathological examination showed nonspecific colitis. At the age of 68 years, another colonoscopy revealed redness and vascular pattern loss of the ascending colon ; however the rectum was not involved. Histopathological examination showed inflammatory cell infiltration with crypt abscess. He was diagnosed with atypical ulcerative colitis. Mesalazine therapy was started at an initial dose of 4000mg/day and gradually tapered. At the age of 73 years, another colonoscopy revealed deterioration of mucosal inflammation. After further examination, he was diagnosed with diverticular colitis. Another course of mesalazine therapy was started, with a dose of 3600mg/day, which was gradually tapered. After a year of treatment, the latest colonoscopy revealed mucosal healing ; the patient is still being followed up regularly.
