Anal transitional zone cancer after restorative proctocolectomy and ileoanal anastomosis in familial adenomatous polyposis: report of two cases.

PURPOSE

Restorative proctocolectomy with ileal pouch-anal anastomosis is accepted as the surgical treatment of choice for many patients with familial adenomatous polyposis. The risk of cancer developing in the ileal pouch after this surgery is unknown. Cancer may arise from the ileal pouch after restorative proctocolectomy, but that arising from the anal transitional zone has not been documented in familial adenomatous polyposis. We report two cases of this cancer from the anal transitional zone in patients with familial adenomatous polyposis, with a review of the literature.

METHODS

All patients with familial adenomatous polyposis treated with restorative proctocolectomy and ileal pouch-anal anastomosis in The Cleveland Clinic were included in the study. Patients whose surveillance biopsy of the anal transitional zone revealed invasive adenocarcinoma were studied.

RESULTS

Among a total of 146 patients with familial adenomatous polyposis who underwent restorative proctocolectomy and ileal pouch-anal anastomosis from 1983 to 2001 in our institution, none developed cancer of the anal transitional zone at up to 18 years of follow-up. However, there were two patients, both of whom underwent surgery elsewhere but who were followed up here, who developed invasive adenocarcinoma of the anal transitional zone. In one of them, cancer was diagnosed three years after a double-stapled ileal pouch-anal anastomosis, whereas in the other, cancer occurred eight years after a straight ileoanal anastomosis with mucosectomy.

CONCLUSIONS

Cancer may develop in the anal transitional zone after restorative proctocolectomy with ileal pouch-anal anastomosis for familial adenomatous polyposis. Long-term surveillance of the anal transitional zone needs to be emphasized.