Purpose: This study aims to assess the correlation between the tissue types found in the circular stapler donut at the time of initial double-stapled ileal pouch-anal anastomosis (DS-IPAA) and during subsequent periodic routine random biopsy. Secondarily, we sought to assess the risk of dysplasia, carcinoma or mucosal ulcerative colitis (MUC) recurrence in the retained mucosa.
Methods: The pathology reports of 91 patients (48 males, 43 females) who were operated upon for MUC from September 1988 to June 1997 and were reviewed and had two follow up visits for biopsy. The histological features of the distal donuts and biopsies of retained mucosa obtained at yearly interval follow-up were assessed in order to determine the epithelial tissue type (columnar, transitional and squamous), inflammation, recurrence of MUC and presence of dysplasia or malignancy.
Results: Median age at surgery was 43 (range 15-71) years and duration of MUC was 9.6 (range 0.3-42) years prior to surgery. The anastomosis was performed at a median height of 1.0 (range 0-2.5) cm cephalad to the dentate line and biopsy follow-up was undertaken at median 34 (range 2-110) months after DS-IPAA. The distal donuts were analysed in all cases, as were 305 follow-up biopsies (median 3.4; range 1-7 per patient). Although columnar epithelium (CE) was found in 62 (68%) donuts, it was absent on follow-up biopsy in 16 (26%) of these patients. Conversely, although no CE was identified in 29 (32%) donuts, it was identified in 11 (38%) of these patients during follow-up biopsy. CE in the donut was a significant predictor of CE in subsequent biopsies (P = 0.0012). The histological features consistent with MUC were seen in the biopsies from the retained mucosa in 15 (16%) patients from 0.3 to 7.6 years after DS-IPAA. While eight (9%) patients exhibited dysplasia or adenocarcinoma in the excised colon or rectum, none of the patients had either dysplastic changes or carcinoma within the retained mucosal biopsies.
Conclusion: The correlation between CE in the circular stapler donut and at follow-up biopsy was high. However since CE developed in some patients in whom no CE was present in the distal donuts, regardless of the epithelial tissue type finding at the time of DS-IPAA, periodic follow-up biopsy should be obtained.