Ileostomy polyps, adenomas, and adenocarcinomas.

Ileostomy polyps are uncommon and poorly described. The aim of this study was to undertake a retrospective clinicopathological review of ileostomy polyps. Seven patients with 60 polyps arising on ileostomies performed for ulcerative colitis were studied. The histopathological evaluation of archival ileostomy biopsy specimens, polypectomy or excision specimens, and clinical review of patient records was undertaken. Fifty of 60 polyps were inflammatory cap polyps and six further polyps were composed of granulation tissue only. They occurred anywhere on the stoma at any time after ileostomy construction and were strongly associated with overt stomal prolapse. Four neoplastic polyps were identified in two patients 27-36 years after ileostomy construction; all occurred at the mucocutaneous junction. One patient presented with a 2 cm polypoid invasive adenocarcinoma while in the second a 1.7 cm polypoid mucinous adenocarcinoma and a 0.7 cm ileal tubular adenoma with high grade dysplasia occurred at the site of excision of a cap polyp showing focal low grade adenomatous dysplasia six years previously. Neoplastic and non-neoplastic polyps could not be differentiated clinically. It was found that most ileostomy polyps are inflammatory cap polyps associated with stomal prolapse. Less common are polypoid adenomas or adenocarcinomas arising at the mucocutaneous anastomosis > 20 years after ileostomy construction. To prevent ileostomy carcinoma it is recommended that a biopsy of all polyps at the mucocutaneous anastomosis and of any non-prolapse associated polyps elsewhere on the stoma occurring > 15 years after ileostomy construction is done.