Adenocarcinoma of the ileostomy: the latent risk of cancer after colectomy for ulcerative colitis and familial polyposis.

A case of a primary adenocarcinoma of an ileostomy is reported along with 15 other cases collected from the literature. These rare tumors are seen on the average 24 years after colectomy with ileostomy and in all cases are associated with a past history of ulcerative colitis or familial polyposis. Most of the reported cases of these tumors have appeared in the literature within the past 5 years, suggesting that there is a rising incidence of this disease corresponding to completion of a biologic latency period that began when the Brooke ileostomy was introduced for ulcerative colitis in 1951. In our case a mucinous adenocarcinoma occurred at the ileostomy site 34 years after colectomy. Adjacent to the tumor was mucosa showing colonic metaplasia and focal dysplasia. Subsequent biopsy specimens of the revised stoma showed inflammatory lesions morphologically suggestive of inflammatory (pseudo) polyps. The clinical and morphologic features in this case suggest that there is transition from ileal mucosa to colonic mucosa to colonic dysplasia to adenocarcinoma. Annual evaluation of the ileostomy for colonic metaplasia, inflammatory lesions consistent with ulcerative colitis and dysplasia, is recommended. In the presence of dysplasia, stomal revision is advised. Wide local excision is advised for adenocarcinoma.