Case 6 -

Prolapse Injury Laura W. Lamps, M.D. Audrey J. Lazenby, M.D. Joel K. Greenson, M.D.

Clinical Presentation: This 22 year old woman presented with diarrhea, occasionally alternating with constipation, and bleeding per rectum. Case 6 - Figure 1 - Low magnification view shows prolapse polyp with mushroom-like cap of fibrinopurulent exudates. Case 6 - Figure 2 - Architectural distortion, crypt abscesses, and reactive epithelial atypia within a prolapse polyp, accompanied by marked hemosiderin deposition. Case 6 - Figure 3 - Higher magnification emphasizes congested capillaries within lamina propria, as well as hypertrophic muscularis mucosa extending into the mucosa in a perpendicular fashion. Endoscopic Findings: The endoscopist noted a beefy, friable 1cm polyp in the rectum. Diagnosis : Prolapse injury General Comments: Mucosal prolapse polyps present in a variety of clinical scenarios, including those of diverticular disease, the solitary rectal ulcer syndrome (SRUS), and at ostomy sites. Clinically, they are often a feature of SRUS, which usually occurs in young women with alternating diarrhea and constipation, rectal prolapse, and bleeding. When prolapse occurs at the anal verge and forms a polyp it is also known as the inflammatory cloacogenic polyp. Pathologic features: Grossly, prolapse polyps are friable, ulcerated polyps with an irregular shape and a beefy, red appearance. The surface may be granular and ulcerated, and occasionally the polyps have an unusual brown color if they contain abundant hemosiderin. These lesions are most common in the distal colon and anorectum, but may appear anywhere in the lower GI tract (and rarely in the small bowel and stomach). They are usually solitary, but may be multiple. The histologic features are similar regardless of the underlying disorder. Histologically, the appearance depends on the stage of development of the polyp. In general, the mucosa is inflamed, and the glands have a reactive appearance with crypt elongation and dilatation. There may be significant crypt architectural distortion. The surface mucosa may be serrated and tufted with goblet cell hypertrophy. Often there is superficial ulceration with a "fibrin cap" of fibrinopurulent debris. The lamina propria is often very vascular, with numerous congested capillaries and hemosiderin deposition. The characteristic finding in mucosal prolapse at any site is the presence of fibromuscular hyperplasia of the lamina propria. The presence of strands of smooth muscle growing perpendicular to colonic crypts is diagnostic of prolapse. Occasionally, the amount of fibrosis can overshadow the smooth muscle proliferation. Pathogenesis: In SRUS, The process is thought to be due to malfunction of the puborectalis muscle such that excessive straining upon defecation results. This leads to mucosal prolapse that ultimately may ulcerate and form polypoid masses. Prolapse polyps at any site are therefore caused by prolapse of the intestinal mucosa into the lumen with subsequent ischemia, mucosal damage, inflammation, and repair. Differential diagnosis: Prolapse polyps may mimic many other types of polyps, including juvenile polyps, inflammatory polyps of idiopathic inflammatory bowel disease, hyperplastic polyps, and adenomatous polyps. The presence of smooth muscle proliferation may mimic a Peughtz-Jehgers polyp, however, the branching or arborizing architecture of these lesions will be absent. In some cases glands may become trapped in the submucosa forming what is know as colitis cystica profunda. Care should be taken to avoid diagnosing this process as a neoplasm; generally speaking the epithelium lining the cysts in colitis cystica profunda is cytologically bland. It is important to remember that prolapse polyps may contain significant reactive atypia, as well as serrated epithelium at the surface, that mimics neoplastic polyps. Finally, as prolapse lesions contain distorted and inflamed mucosa, it is also possible to misinterpret these findings as representing inflammatory bowel disease, especially when ulcers dominate the picture. The presence of smooth muscle growing between the crypts is the best clue that one is dealing with mucosal prolapse rather than chronic inflammatory bowel disease. In general, the presence of the fibrinopurulent debris at the surface, as well as the perpendicular splaying of the muscularis mucosa, may help in resolving the differential. A clinical history of prolapse or an associated condition may be of invaluable assistance. Natural History and Treatment: In the intestine, the polyps themselves are completely benign and the patient outcome is determined by the underlying disorder. If the polyps cause problematic bleeding they may be excised. Ultimately, however, patients with prolapse problems respond better to nonsurgical management such as bulk laxatives and stool softeners. 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