Non neoplasticColonic polyps


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Non neoplasticColonic polyps

  1. 1. Non-neoplastic Colonic Polyps Polyps are most common in the colon but may occur in the esophagus, stomach, or small intestine. Lecture 14 By Dr Mohammad Manzoor Mashwani BKMC Mardan
  2. 2. Definition of Polyp A polyp is defined as any growth or mass protruding from the mucous membrane into the lumen. • Classification: • Stalked or pedunculated polyp • Sessile polyp As sessile polyps enlarge, proliferation of cells adjacent to the polyp and the effects of traction on the luminal protrusion, may combine to create a stalk. Non-neoplastic & Neoplastic Polyps
  3. 3. Non-neoplastic Colonic Polyps Non-neoplastic Polyps Hyperplastic polypsHamartomatous polyps Juvenile polyps Peutz-Jeghers polyps Inflammatory polyps Lymphoid polyps 90% most common
  4. 4. Neoplastic Colonic Polyps • Neoplastic Epithelial Lesions • Benign polyps • Adenomas • Malignant lesions Adenocarcinoma Squamous cell carcinoma of the anus
  5. 5. Non-neoplastic polyps of intestine Hyperplastic polyps Hamartomatous polyps Juvenile polyps Peutz-Jeghers polyps Inflammatory Lymphoid polyps polyps
  6. 6. Non-neoplastic Polyps • The overwhelming majority of intestinal polyps occur sporadically, particularly in the colon, and increase in infrequency with age. • Non-neoplastic polyps represent 90% of all epithelial polyps in the large intestine and are found in more than half of all persons age 60 years or older.
  7. 7. I. Hyperplastic Polyps (Metaplastic) • The most common amongst all epithelial polyps. • Most common in the left colon (rectosigmoid). • Called hyperplastic because there is epithelial hyperplasia at the base of crypts, and metaplastic as there are areas of cystic metaplasia. • More common in elderly (6th-7th decade).
  8. 8. Pathogenesis The pathogenesis of hyperplastic polyps is incompletely understood, but they are thought to result from decreased epithelial cell turnover and delayed shedding of surface epithelial cells, leading to a “pileup” of goblet cells and absorptive cells.
  9. 9. Morphology GROSS- Most commonly found in the • Small ( <5 mm in diameter), multiple, left colon (rectosigmoid) and smooth-surfaced, sessile. Microscopy - composed of mature goblet and absorptive cells, long & cystically dilated glands & crypts. • The delayed shedding of these cells leads to crowding that creates the serrated surface (Saw-toothed) architecture that is the morphologic hallmark of these lesions.
  10. 10. Hyperplastic polyp. A, Polyp surface with irregular tufting of epithelial cells. B, Tufting (bunch) results from epithelial overcrowding. C, Epithelial crowding produces a serrated architecture when glands are cut in cross-section.
  11. 11. Hamartomatous polyps Occur sporadically and in the context of various genetically determined or acquired syndromes . Recall that hamartomas are tumor-like growths composed of mature tissues that are normally present at the site in which they develop. Although Hamartomatous polyposis syndromes are rare, they are associated intestinal and extra-intestinal manifestations and the need to screen family members. important to recognize because of
  12. 12. Juvenile Polyps (Retention polyps) • Juvenile polyps are the most common type of hamartomatous polyp. • Juvenile polyps are focal malformations of the mucosal epithelium and lamina propria. • These may be sporadic or syndromic. • The vast majority of juvenile polyps occur in children less than 5 years of age. • When present in adults, polyps with identical morphology are sometimes confusingly referred to as inflammatory polyps.
  13. 13. • The majority of juvenile polyps are located in the rectum and most present with rectal bleeding. In some cases prolapse occurs and the polyp protrudes through the anal sphincter. • Sporadic juvenile polyps are usually solitary lesions and may be referred to as retention polyps. • In contrast, individuals with the autosomal dominant syndrome of juvenile polyposis have from 3 to as many as 100 hamartomatous polyps and may require colectomy to limit the chronic and sometimes severe hemorrhage associated with polyp ulceration.
  14. 14. • stomach and small bowel. Pulmonary arteriovenous malformations are a A minority of patients also have polyps in the recognized extra-intestinal manifestation of the syndrome. Dysplasia occurs in a small proportion of (mostly syndrome associated) juvenile polyps, and the juvenile polyposis syndrome is associated with increased risk for the development of colonic adenocarcinoma.
  15. 15. Morphology Individual sporadic and syndromic juvenile polyps often are indistinguishable. Gross- pedunculated, smooth surfaced, reddish lesions that are <3 cm in diameter and display characteristic cystic spaces on cut sections. Microscopic examination – cystically dilated glands filled with mucin and inflammatory debris Spherical,
  16. 16. Juvenile polyposis. A, Juvenile polyp. Note the surface erosion and cystically dilated crypts. B, Inspissated mucous, neutrophils, and inflammatory debris can accumulate within dilated crypts.
  17. 17. Peutz-Jeghers Syndrome A rare autosomal dominant disorder defined by the presence of multiple gastrointestinal hamartomatous polyps and mucocutaneous hyperpigmentation that carries an increased risk of several malignancies, including cancers of the colon, pancreas, breast, lung, ovaries, uterus, and testes, as well as other unusual neoplasms.
  18. 18. • Intestinal polyps are most common in the small intestine, although they may also occur in the stomach and colon and, rarely, in the bladder and lungs.
  19. 19. Morphology • Gross- More commonly situated in the small intestine. Often large (variable), multiple & pedunculated with lobulated contour. • Microscopy- characteristic arborizing network of connective tissue, smooth muscle, lamina propria, and glands lined by normal-appearing intestinal epithelium. • Tree-like branching of muscularis mucosae. The gland may show hyperplasia & cystic change.
  20. 20. Peutz-Jeghers polyp. A, Polyp surface (top) overlies stroma composed of smooth muscle bundles cutting through the lamina propria. B, Complex glandular architecture and the presence of smooth muscle are features that distinguish Peutz-Jeghers polyps from juveni le polyps.
  21. 21. Inflammatory Polyps (Pseudopolyps) The polyp that forms as part of the solitary rectal ulcer syndrome is an example of the purely inflammatory lesion. Patients present with the clinical triad of rectal bleeding, mucus discharge, and an inflammatory lesion of the anterior rectal wall.
  22. 22. • The underlying cause is impaired relaxation of the anorectal sphincter, creating a sharp angle at the anterior rectal shelf. This leads to recurrent abrasion and ulceration of the overlying rectal mucosa. Chronic cycles of injury and healing produce a polypoid mass made up of inflamed and reactive mucosal tissue.
  23. 23. • Inflammatory polyps or pseudopolyps appear due to reepithelialisation of the undermined ulcer & overhanging margins in inflammatory bowel disease, most frequently in ulcerative colitis & sometimes in Crohn’s disease.
  24. 24. A projecting mass of hypertrophied mucous membrane (as in the stomach or colon) resulting from local inflammation
  25. 25. Solitary rectal ulcer syndrome. A, The dilated glands, proliferative epithelium, superficial erosions, and inflammatory infiltrate are typical of an inflamatory polyp. However, the smooth muscle hyperplasia within the lamina propria suggests that mucosal prolapse has also occurred. B, Epithelial hyperplasia. C, Granulation tissue-like capillary proliferation within the lamina propria caused by repeated erosion and re-epithelialization .