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Colonic polyps complicating ureterosigmoidostomy.

Polypoid tumours of the small and large intestine have been recognized as a complication of the implantation of ureters into the bowel for many years. Some cases could be recurrences of the urothelial tumour which necessitated the original operation or alternatively others may be tumours arising from the bowel epithelium itself. Malignant and benign varieties of such bowel tumours have been reported, although the description of some of the latter have suggested that they were not true tumours but some variety of 'polyp'. We describe here two polyps arising in the colon some 22 years after ureterosigmoidostomy and discuss the probably mixed nature with elements of both juvenile polyp and tubular adenoma.

Adenoma↗

Hyperplastic-like colon polyps that preceded microsatellite-unstable adenocarcinomas.

We compared hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas to incidental hyperplastic polyps to identify distinguishing morphologic criteria. The study group included 106 hyperplastic-like, nonadenomatous, serrated polyps, most from the ascending colon in 91 patients; the control group included 106 rectosigmoid hyperplastic polyps from 106 patients in whom adenocarcinoma did not develop. Study group polyps had an expanded crypt proliferative zone, a serrated architectural outline that became apparent in the basilar crypt regions, basilar crypt dilation, inverted crypts, and a predominance of dysmaturational crypts (crypts with minimal cell maturation). In contrast, control group polyps had a proliferative zone confined to the basal crypt region, serrated architecture that became apparent in the superficial crypt region, rare to no basilar crypt dilation, and rare or no dysmaturational crypts. Hyperplastic-like polyps that preceded microsatellite-unstable adenocarcinomas had a distinctive constellation of morphologic features related to altered and decreased cell function and control that resulted in dysmaturational crypts. Dysmaturation constitutes a range of morphologic alterations, some of which overlap with incidental-type innocuous hyperplastic polyps. The morphologic features described herein provide initial guidelines to identify this potentially important subset of premalignant serrated-like polyps.

Adenocarcinoma↗

Colon cancer screening and the evaluation and follow-up of colonic polyps.

Approximately 150,000 new cases of colon cancer are diagnosed each year, and the mortality rate continues to be greater than 50% of those diagnosed. Screening for colon cancer should be part of the routine health maintenance program of the primary physician. Use of history, physical examination, and sigmoidoscopy is part of a complete program. Colonoscopic removal of polyps reduces cancer risk.

Colonic Neoplasms↗

Lack of peptide YY immunoreactivity in adenomatous colonic polyps: evidence in favor of an adenoma-carcinoma sequence.

The aim of endoscopic polypectomy is to prevent colorectal cancer, as it is assumed that most, if not all, large bowel cancers are derived from adenomatous polyps. While it is now recognized that colonic endocrine cells, like other mucosal epithelial cells, have an endodermal origin, they are relatively sparse components of large bowel tumors. Peptide YY (PYY) is the most abundant endocrine regulatory peptide localized to the distal bowel. Endocrine cells, like the other cells of the mucosal epithelia, are derived from a common stem cell in the base of the crypts. The presence of endocrine peptides may thus be viewed as a marker for cellular differentiation in the gut. PYY was therefore measured in colonic carcinomas and adenomatous polyps, as its absence would be evidence in favor of genetic alterations in epithelial stem cell maturation. PYY concentrations in extracts of surgically removed colonic carcinomas (n = 22) from all regions were very low compared with those of adjacent normal bowel. Similarly, PYY concentrations in extracts of polyps (n = 39) obtained during endoscopic polypectomy were also very low when compared with those of adjacent normal mucosa. These varied between 1 and 11% of the normal epithelial content, depending upon the region. Low PYY levels appeared to reflect the malignant potential of these lesions: highest in tubular polyps, lower in villous polyps, and lowest in carcinomas. The very low concentrations of PYY in adenomatous polyps, like those of colonic cancer, are consistent with epithelial dysplasia and the incomplete formation of mucosal endocrine cells. These findings support the hypothesis of an adenoma to carcinoma sequence in colonic cancer.

Adenoma↗

Distribution of colonic polyps: increased incidence of proximal lesions in older patients.

Several recent studies have shown a proximal shift in the distribution of colonic carcinoma compared to older studies. Because of the association between polyps and cancer, the authors evaluated the distribution of colonic polyps in 3,664 consecutive patients who had a colon examination over a period of 14 months. A total of 967 colorectal polyps were found in 633 patients. In all, 502 polyps (52%) were proximal to the rectosigmoid. Older patients had significantly more right-sided polyps and fewer rectosigmoid lesions. Large polyps occurred more frequently in the right colon, and this was also statistically significant. Gender has no effect on polyp distribution. The authors conclude that the importance of screening for polyps, particularly on the right side of the colon, increases with age.

Adult↗

Reduced glutamine content in colonic polyps.

BACKGROUND: Glutamine is the most abundant amino acid in the body. It has a key role in nitrogen metabolism and is a major source of energy for the enterocyte and many other cells. Glutamine is also essential for tumor growth, and marked changes in organ glutamine metabolism are characteristic in cancer patients. METHODS: We have investigated the catabolism of glutamine in a classic premalignant condition: the colonic adenomatous polyp. The content of glutamine and activity of two catabolic enzymes, glutamine transferase and phosphate-dependent glutaminase, were studied in normal colon and in polyp mucosa. RESULTS: Free glutamine content and activity of glutaminase were significantly lower in polyps than in their adjacent mucosa. Glutamine transferase activity was significantly lower in polyp mucosa than in normal colon controls. CONCLUSIONS: Adenomatous polyps might behave as a glutamine trap, channeling glutamine to protein and nucleic acid synthesis. These changes in glutamine catabolism could play a role in colonic neoplasia pathogenesis.

Acyltransferases↗

[Colonic polyps: an analysis of the endoscopic and histopathological aspects].

The present study is a retrospective analysis of the endoscopic and histologic features of 728 polyps resected from 422 patients during the years 1980 to 1991. Mean age of the patients was 52 years (5 to 87), 63% male and 37% female. The histology of the lesions showed: adenoma: 60.3%, hyperplastic: 31.7; juvenile: 2.3% and miscellaneous: 5.7%. The 439 adenomas where found in 270 patients of which 151 (55.9%) were male and 119 (44.1%) female. The 231 hyperplastic polyps where found in 113 patients: 66 (58.4) male and 47 (41.6) female. All the hyperplastic polyps where less than 20 mm in diameter. Of the adenomas, 385 (87.7%) where less than 20 mm in diameter and had macroscopic appearance similar to the hyperplastic polyps. Of the 439 adenomas, 218 (49.6) where pediculated and 221 (50.4%) sessile. Of the hyperplastic polyps 53 (22.9%) where pediculated and 178 (77%) sessile. Of the adenomas, 351 (80%) where tubular and 88 (22%) had a villous component, most of the tubular adenomas where less than 15 mm in diameter and the villous component was more frequent as the polyps increased in size. Of the adenomas, 139 (30%) had dysplasia and of these 10% had cancer which represents a total of 3% of all the adenomas in this series. The grade of dysplasia was more severe as the adenomas was larger in size or had villous component. The polyps were located: 69.6 in the distal colon at the reach of the flexible sigmoidoscope and 30.4% in the proximal colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗