Review Dysplasia in the ileoanal pouch S. E. Duff*, S. T. O’Dwyer*, L. Hulte ´n , R. Wille ´nà and N. Y. Haboubi§ *Department of Surgery, Christie Hospital NHS Trust, Manchester, UK,  Institute of Surgical Science and àDepartment of Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden and §Department of Pathology, Trafford General Hospital, Manchester, UK Received 6 May 2002; accepted 6 May 2002 Abstract Formation of an ileo-anal pouch is an accepted technique following colectomy in the surgical management of ulcerative colitis (UC) and familial adenomatous poly- posis (FAP). The configuration of pouches and anasto- motic techniques has varied over the last two decades. The increased use of stapling devices in formation of the pouch-anal anastomosis avoids the need for endoanal mucosal stripping and may contribute to improved functional results, but leaves a ’columnar cuff’ of residual rectal mucosa in situ. Concerns regarding the long-term safety of the ileo-anal pouch have been raised by reports of the occurrence of dysplasia in the pouch mucosa and 15 cases of adenocarcinoma. In UC, persistence of underlying disease in the residual rectal mucosa, anal transition zone and columnar cuff provides the site for development of dysplasia and malignancy. Pouchitis is unlikely to be a major cause of dysplasia or malignancy, as long-term follow-up of patients with Koch pouches has demonstrated. In FAP, any persistent rectal mucosa and mucosa of the small intestine is at risk of adenomatous dysplasia due to the genetic alterations causing the disease. Long-term surveillance should focus on all FAP pouch patients, and in UC patients should be directed towards the diagnosis of residual rectal mucosa in the area distal to the pouch anastomosis. Specialist histopatholo- gical opinion is essential in the diagnosis of dysplasia in the ileo-anal pouch. Keywords Restorative proctocolectomy, ulcerative colitis, adenomatous polyposis coli, precancerous conditions Introduction Ulcerative colitis (UC) is an inflammatory condition of the colon starting distally, extending from the rectum for a variable extent to the proximal colon. Long-term duration, severe and extensive disease can be complicated by dysplastic change of the epithelium which may progress to full blown invasive carcinoma [1,2]. Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited condition that develops as a con- sequence of mutations in the adenomatous polyposis coli (APC) gene on chromosome 5q. Affected individuals develop multiple adenomas throughout the colon and rectum and if untreated all will develop invasive adeno- carcinoma. FAP is also associated with the development of extra-colonic malignancies [3] and upper gastrointes- tinal tract adenomas, which are, apart from peri-ampul- lary lesions, of low malignant potential [4]. On long-term follow-up, 4.5% of FAP patients develop upper gastroin- testinal carcinoma [5]. Treatment of FAP and dysplasia in long-standing UC involves colectomy. Traditional approaches involved proctocolectomy leaving an end ileostomy, however, current practice involves restorative proctocolectomy, i.e. ileo-anal pouch construction, avoiding the necessity for a permanent stoma. The ileo-anal pouch The development of sphincter preserving procedures for ulcerative colitis has a long and interesting history (reviewed in [6]). In 1978, Parks & Nicholls [7] described a technique of restorative proctocolectomy for the treatment of UC. The technique involved removal of the diseased colon down to the upper half of the rectum and creation of a reservoir fashioned from triplicated ileum (the S pouch). An endoanal procedure was also performed stripping the remaining rectal mucosa from the level of the dentate line upwards. A per-anal anastomosis was formed, leaving a cuff of denuded rectal musculature supporting the S-pouch in the pelvis (Fig. 1a). This operation achieved removal of the tissue subject to disease with acceptable functional results. Unfortunately, the procedure had a high morbidity, Correspondence to: Dr S. E. Duff, Department of Surgery, Christie Hospital NHS Trust, Wilmslow Road, Manchester, UK. E-mail: sarah.duff@christie-tr.nwest.nhs.uk 420 Ó 2002 Blackwell Publishing Ltd. Colorectal Disease, 4, 420–429