Incidence of Dysplasia in Pelvic Pouches in Pediatric Patients After Ileal Pouch-Anal Anastomosis for Ulcerative Colitis

Abstract

Similar morphologic changes can be seen in ileal pouches in pediatric and adult patients. There seemed to be no increased risk of dysplasia in children and young adults who had undergone ilial pouch-anal anastomosis surgery for ulcerative colitis during a 5 year follow-up. Because the long-term risk of development of dysplasia is unknown, an initial screening should be performed 5 years after the creation of a pelvic pouch in children or when the total disease duration exceeds 7 years. Once identified, patients with Type C mucosa should have annual screening for dysplasia until further data become available.

Mucosal Assessment for Dysplasia and Cancer in the Ileal Pouch Mucosa in Patients Operated on for Ulcerative Colitis—A 30-Year Follow-Up Study

“…This concern was expressed in reports of "Excess of sulfated sialomucin formation," which is known as an obligate precancer finding, 18,19,5,20 "atypia and dysplasia," 21,10 "high-grade dysplasia," 7 "low-grade dysplasia," 22,6 "aneuploidy changes," 7,22,24 and eventually the reports of "frank invasive adenocarcinoma in long-standing diverted pouch." 25 However, others who were unable to demonstrate dysplasia or neoplasia 26,8 reported contradictory results. Common to all of these studies was a relatively short follow-up time, ranging from five to nine years.…”

“…However, other groups who were unable to demonstrate either dysplasia or neoplasia have reported contradictory results. 26,8 The major concern about the pelvic pouch is the possibility of retained islets of rectal mucosa that may be the origin of the adenocarcinoma in patients with a pelvic pouch. No such risk is possible in the Kock pouch.…”

“…6,7 Some reports suggest that dysplastic transformation is a rare phenomenon and, therefore, the risk of further progression to cancer should be small. 8 However, the observation time in most studies is relatively short, and therefore there are doubts as to the reliability of these statements. Studies on extensive and longstanding ulcerative colitis show evidence that at least 10 to 20 years' exposure to this condition is needed before there is a subsequent risk of cancer developing in the large-bowel mucosa.…”

Pelvic Cancer Ten Years after Restorative Proctocolectomy in Indeterminate Colitis: Report of a Case

“…26,27 The risk of dysplasia or cancer appearing within the pouch mucosa after restorative proctocolectomy is small. [28][29][30][31] These data strongly suggest that malignant degeneration of the pouch mucosa is an extremely rare event and probably takes decades to become manifest.…”

Adenocarcinoma Arising in the Middle of Ileoanal Pouches

“…6Y10 Most of these pouch polyps have been described as small, tubular adenomas with mild dysplasia and the chances of progression to pouch cancer have been considered rare. 11,12 As the observational times in these studies have been relatively short, doubts exist about the reliability of these conclusions regarding malignant transformation. Nonetheless, Beveridge et al described the first two large villous adenomas arising in two FAP patients from St. Mark's Hospital and factors were considered that may determine the risk of malignant transformation.…”