Inflammatory cloacogenic polyp: relationship to solitary rectal ulcer syndrome/mucosal prolapse and other bowel disorders.

The clinicopathologic features of nine patients with inflammatory polyps of the anorectal transition zone (inflammatory cloacogenic polyp, ICP) were reviewed. All polyps were characterized histologically by crypt hyperplasia and a thickened muscularis mucosa arising beneath a surface epithelium consisting of variable proportions of squamous, columnar, and often transitional epithelium. Tubulovillous architecture was characteristic. Sialomucin predominated over sulfomucin in eight of nine cases. One polyp displayed focal dysplasia and condylomatous features, while two others had associated hemorrhoids. Three cases had been previously diagnosed as adenomas. Seven patients were women, and two were men; their median age was 54 years (range, 17 to 85). Clinical presentation was most commonly intermittent rectal bleeding, and the clinical diagnosis was anal polyp or hemorrhoids in all cases. Six patients had the solitary rectal ulcer syndrome (SRUS) and/or evidence of mucosal prolapse. Papillomavirus was demonstrated by histochemical and immunohistochemical methods in one case in which multiple foci of dysplasia were also noted. Two patients had Crohn's disease, and the remaining patient had a coexistent adenocarcinoma located several centimeters proximal to his ICP. The pathologist and clinician must be aware that although ICP is often associated with SRUS/mucosal prolapse, it may occur in other clinical settings.