[Anorectal localization of chronic inflammatory diseases of the intestines]

In Ulcerative Colitis (UC), the rectum is always involved, but the disease may be extended to the left colon (distal colitis) or the entire organ (pancolitis). Secondary perineal lesions (erythema, fissures, hemorrhoids) are limited to local irritation related to the diarrheic syndrome; specific ano-rectal lesions are related to the mucosal inflammatory process, but others pathological situations may be observed and are due to the postoperative status (stenotic ileo-anal anastomosis, pouch inflammation). Ano-rectal localisation of Crohn's Disease (CD), sometimes underestimated, is clinically more complex (abscess, fistula, ulcer, etc) and requires precise classical (endoscopy, conventional radiology) or more modern (echo-endoscopy, nuclear magnetic resonance) investigations. The treatment is more difficult (medical conservative, "a minima" or more extended surgery). Differential diagnosis, symptoms, methods of investigation and appropriated therapeutical choices are successively developed.