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

Background: The purpose of this study was to evaluate the incidence of dysplasia and the mucosal adaptation patterns of pelvic pouches in children and adolescents who had undergone ileal pouch-anal anastomosis for ulcerative colitis.

Methods: Between 1982 and 1996, 176 pediatric patients with ulcerative colitis underwent ilial pouch-anal anastomosis. Seventy-six patients were followed up after surgery at the Cleveland Clinic. Pouch biopsy specimens were reviewed for dysplasia and to determine mucosal adaptation patterns. Fifty-eight of the 76 patients had an average of three mucosal biopsies during a mean follow-up of 5 years. Demographic and surgical data were abstracted from archives of medical records. All previously obtained pouch biopsy specimens were re-evaluated by a single pathologist to ensure standardized interpretation.

Results: No dysplasia was identified in screening specimens of 76 children and adolescents including 5 patients who showed dysplasia in resected colon specimens. The pattern of mucosal adaptation was categorized using previously reported criteria. Type A was defined as normal mucosa or mild villous atrophy with no or mild inflammation. Type B mucosa showed transient atrophy with temporary moderate inflammation followed by normalization of architecture. Type C mucosa was defined as a pattern of persistent atrophy with severe inflammation. In the study cohort, the patterns of mucosal adaptation, type A (56.9%; n = 33), type B (32.8%; n = 19), and type C (10.3%; n = 6), were comparable with those reported in adults. The rate of pouch failure and diagnosis of Crohn's disease were similar in each group and were not related to the specific adaptation pattern. Most of the patients with type C mucosa had clinical symptoms of pouchitis requiring periodic antibiotic therapy. No dysplasia was identified in any biopsy specimen reviewed.

Conclusions: 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.