Non-Neoplastic Disorders of the Intestines
Case 6 -
Laura W. Lamps, M.D.
Audrey J. Lazenby, M.D.
Joel K. Greenson, M.D.
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.
The endoscopist noted a beefy, friable 1cm polyp in
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.
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
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,
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.
- Chetty R, Bhathal PS, Slavin JL. Prolapse-induced inflammatory polyps of the colorectum and anal transitional zone. Histopathology 23:63-7, 1993.
- Kelly JK. Polypoid prolapsing mucosal folds in diverticular disease. Am J Surg Pathol 15:871-8, 1991.
- Bass J, Soucy P, Walton M, et al. Inflammatory cloacogenic polyps in children. J Pediatr Surg 30:585-8, 1995.
- Du Boulay CEH, Fairbrother J, Isaacson PG. Mucosal prolapse syndrome - a unifying concept for solitary rectal ulcer syndrome and related disorders. J Clin Pathol 36:1264-8, 1983.
- Saul SH, Sollenbeger LC. Solitary rectal ulcer syndrome: its clinical and pathological underdiagnosis. Am J Surg Pathol 9:411-21, 1985.
- Nakamura S-I, Kino I, Akagi T. Inflammatory myoglandular polyps of the colon and rectum. A clinopathological study of 32 pedunculated polyps, distinct from other types of polyps. AM J Surg Pathol 16:772-9, 1992.
- Kiko R, Rutter P, Riddell RH. The Solitary Ulcer Syndrome of the Rectum. Clinics in Gastroenterology 4:505-530;1975.
- Shepherd, N.A. Pathological mimics of chronic inflammatory bowel disease. Journal of Clinical Pathology 44:726-733, 1991.
- Niv, Y. and Bat, L. Solitary Rectal Ulcer Syndrome--Clinical, Endoscopic, and Histologic Spectrum. The American Journal of Gastroenterology 81(6):486-491, 1986.
- Levine, D.S., Surawicz, C.M., Ajer, T.N., Dean, P.J. and Rubin, C.E. Diffuse Excess Mucosal Collagen in Rectal Biopsies Facilitates Differential Diagnosis of Solitary Rectal Ulcer Syndrome from Other Inflammatory Bowel Diseases. Digestive Diseases and Sciences 33(11):1345-1352, 1988.
- Vora, I.M., Sharma, J. and Joshi, A.S. Solitary rectal ulcer syndrome and colitis cystica profunda--a clinico-pathological review. Indian Journal of Pathology & Microbiology 35:94-102, 1992.