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PubMed1998

Effect of penicillin on polyp formation in acute otitis media.

HYPOTHESIS/BACKGROUND: The mucoperiosteal lining of the middle ear cavity is subject to radical changes during and after acute infection. Among these is the formation of mucosal polyps. Previous studies on experimental acute otitis media have shown a marked impact of penicillin on mucosal histomorphology. This study reports on the effect of penicillin administration on polyp formation. METHODS: The mucosa of 75 rat middle ears in a model of acute otitis media was examined. Whole-mount and section preparations from 25 normal ears, 25 ears inoculated with Streptococcus pneumoniae, and 25 inoculated, penicillin-treated ears were inspected for number, size, anatomic localization, and histopathologic morphology of occurring polyps. RESULTS: The total number of polyps was unaffected by penicillin administration, although polyps occurred in fewer ears. The polyps from treated ears tended to be smaller and stalky, appeared later in the timespan covered, and often were located around the tubal orifice. Histopathologic morphology of polyp base, core, and epithelial covering was otherwise unaffected by penicillin. CONCLUSIONS: Administration of penicillin has inconspicuous effect on the formation of polyps in experimental otitis media caused by S. pneumoniae in contrast to a marked impact on mucosal goblet cell density and other histopathologic features reported in previous studies.

Acute Disease↗
PubMed1997

Plasminogen activators in human nasal polyps and mucosa.

Fibrinolysis is one of the processes that are involved in inflammation. In this study we have investigated if it is also involved in bilateral nasal polyposis, a disease with an inflammatory component. Fibrinolytic activity in the nasal mucosa and nasal polyps has been studied in 10 patients with bilateral nasal polyposis. Tissue-type plasminogen activator (t-PA) and urokinase-like plasminogen activator (u-PA) activities and antigen levels have been determined in polyp tissue and control nasal mucosa. t-PA activity is higher in nasal mucosa (median: 4.26 i.u./mg) as compared with nasal polyps (median: 0.65 i.u./mg; p = 0.03); u-PA activity is slightly lower in nasal mucosa (median: 0.040 i.u./mg) as compared to polyps (median: 0.065 i.u./mg; not significant). The percentage of u-PA to t-PA is 7.9% in nasal mucosa and 22.8% in nasal polyps (p < 0.01). The shift towards a higher u-PA/t-PA ratio in nasal polyps suggests an inflammatory process. Plasma levels of C-reactive protein are all within normal limits, which may suggest that PA activity is restricted to a local inflammatory reaction in the airway mucosa. The higher u-PA/t-PA ratio in nasal polyps and the higher levels of u-PA, when compared with the findings in other organs affected by inflammation, indicate that u-PA plays a part in the inflammatory events resulting in nasal polyps.

Adult↗
PubMed2003

Endoscopic removal of large colorectal polyps: prevention of unnecessary surgery?

PURPOSE: Because of the potential risk of malignancy and technical difficulties in achieving complete removal, large colorectal polyps represent a special problem for the endoscopist. The aim of this study was to evaluate the capabilities and risks of endoscopy in complete removal of large colorectal polyps. METHODS: Endoscopic polypectomy of 186 colorectal polyps larger than 3 cm in diameter (range, 3-13 cm) was performed; 141 were sessile and 45 pedunculated. Most of the polyps were located in the rectum (n = 88), sigmoid (n = 63), and cecum (n = 9). The remaining adenomas were situated in other parts of the colon. Sessile polyps were removed using the piecemeal technique. RESULTS: Histology results showed an adenoma in 167 cases, and invasive carcinoma was present in the adenoma in 19 patients. Of the adenomas, 29 were tubulous, 118 tubulovillous, and 20 villous; adenoma with severe dysplasia was found in 49 cases. Complete endoscopic removal was achieved in all sessile and pedunculated polyps. None of the patients with invasive carcinoma who underwent surgical resection (n = 10) had any evidence of tumor in the resected specimen. Bleeding occurred in 4 patients after polypectomy (2 percent). Perforation occurred in 1 patient (0.5 percent), who had an invasive carcinoma of the cecum. There was no procedure-related mortality. During a mean follow-up period of 40 (range, 3-87) months, 6 patients presented with recurrence of a benign adenoma (3 percent), which was treated endoscopically, and 1 patient presented with a recurrent invasive carcinoma, which was treated surgically. CONCLUSIONS: Endoscopic polypectomy is a safe and effective method of treating large colorectal polyps.

Adenocarcinoma↗
PubMed1999

Sulindac sulfone induced regression of rectal polyps in patients with familial adenomatous polyposis.

Sulindac sulfone (Exisulind), a metabolite of the non-steroidal anti-inflammatory drug, sulindac, was evalauted for its effects on the development of rectal polyps in patients with familial adenomatous polyposis. Three cohorts of 6 patients each were given doses of 200, 300, or 400 mg Exisulind twice daily. Hepatotoxicity, shown by elevation in blood transaminase levels, was the dose-limiting toxicity and occurred at the 400 mg bid dose. Due to this toxicity, all patients treated with the 400 mg dose were subsequently reduced to the 200 mg dose level. Subsequently, 2 of the 6 patients were dose-escalated to 400 mg bid dose. The patients were treated with Exisulind for a period of six months. Sixteen of 18 patients had regression of small polyps (> or = 6 mm in diameter) characterized by a flattening of the polyps and a macular "halo" appearance. Histopathologic examination of the polyp biopsy specimens showed a marked increase in the proportion of mucin producing cells in the glands after treatment with Exisulind at all dose levels. Ki-67 staining, a measure of cell proliferation, was higher in the polyps than in normal mucosa. There was no significant change in the proliferation index between baseline and six month values in any of the groups treated with Exisulind or in normal tissues. The median apoptotic labeling index, as determined by the TUNEL technique, was higher in the polyps than in normal-appearing mucosa. Overall, there was no significant change in the apoptotic labeling index between base-line and 6 months in normal-appearing mucosa however, the index in polyps was increased. These results suggest that treatment of FAP patients with Exisulind for a period of six months may lead to regression of small polyps, and that the mechanisms of Exisulind--induced regression appear to be through stimulation of mucus differentiation and apoptosis in glandular epithelium.

Adenomatous Polyposis Coli↗
PubMed1998

A randomized prospective study of the use of endometrial ablation for prevention of recurrent endometrial polyps in breast cancer patients receiving tamoxifen.

Objective: To assess the roles of endometrial ablation in prevention of recurrence of tamoxifen-associated endometrial polyps in breast cancer patients.Design: A randomized prospective study of tamoxifen-treated patients who underwent hysteroscopic removal of endometrial polyps with or without simultaneous resection of the endometrium.Materials and Methods: Twenty consecutive women (aged 43-61 years) undergoing hysteroscopic removal of tamoxifen-associated endometrial polyps were randomized via a computer-generated random table to undergo or not to undergo concomitant endometrial ablation. All patients had undergone endometrial sampling prior to the procedure. The patients were followed for at least 18 months (range 18-24 months). The follow-up included transvaginal ultrasonography every 6 months and hysteroscopy when endometrial irregularity was noted. The main outcome variable was recurrence of endometrial polyps while the occurrence of uterine bleeding was noted.Results: In the 10 study group women, who underwent endometrial ablation, only 1 patient had a 1 x 1 cm endometrial polyp diagnosed and removed during the follow-up period. Seven of the study women remained amenorrheic, and 3 experienced spotting a few days every month. In the control group, a recurrent endometrial polyp, necessitating hysteroscopic removal, was diagnosed postoperatively in 6 women (two-tailed Fisher's Exact test; P <.06).Conclusion: Recurrence of endometrial polyps, one of the most common problems in breast cancer patients receiving long-term treatment with tamoxifen, can be significantly reduced by performing endometrial ablation at the time of hysteroscopic removal of the polyp. The possible risk of occult endometrial cancer is yet to be determined.

Journal Article↗
PubMed2000

Duodenal and ampullary obstruction by a Peutz-Jeghers polyp.

We report a case of Peutz-Jeghers syndrome presenting with obstruction of the second part of the duodenum and the ampulla of Vater by a large intra-luminal polyp leading to duodenal obstruction and obstructive jaundice. CT scan of the abdomen showed a large polypoidal lesion, a caecal polyp and jejuno-jejunal intussusception. At surgery, two intussusceptions were reduced and leading polyps were excised via two enterotomies; the caecal polyp was excised via caecotomy. The duodenal polyp was excised by limited duodenectomy after frozen section has shown no evidence of malignancy. Histopathological study of all the excised polyps including that of the duodenum showed hamartomatous polyps with no malignant changes. Apart from acute bleeding, this case highlights many of the surgical gastrointestinal complications of Peutz-Jeghers syndrome. It also highlights the unusual combined duodenal and common bile duct obstruction by a large Peutz-Jeghers polyp. The controversial association of this syndrome with cancer and management options is also discussed.

Adult↗
PubMed2001

Molecular genetic alterations in hamartomatous polyps and carcinomas of patients with Peutz-Jeghers syndrome.

AIM: To investigate whether mutations in the STK11/LKB1 gene and genes implicated in the colorectal adenoma-carcinoma sequence are involved in Peutz-Jeghers syndrome (PJS) related tumorigenesis. METHODS: Thirty nine polyps and five carcinomas from 17 patients (from 13 families) with PJS were analysed for loss of heterozygosity (LOH) at 19p13.3 (STK11/LKB1 gene locus), 5q21 (APC gene locus), 18q21-22 (Smad4 and Smad2 gene locus), and 17p13 (p53 gene locus), and evaluated for immunohistochemical staining of p53. In addition, mutational analysis of K-ras codon 12, APC, and p53 and immunohistochemistry for Smad4 expression were performed on all carcinomas. RESULTS: LOH at 19p was seen in 15 of the 39 polyps and in all carcinomas (n = 5). Interestingly, six of the seven polyps from patients with cancer had LOH, compared with nine of the 31 polyps from the remaining patients (p = 0.01). In one polyp from a patient without a germline STK11/LKB1 mutation, no LOH at 19p or at three alternative PJS candidate loci (19q, 6p, and 6q) was found. No LOH at 5q was observed. However, mutational analysis revealed an APC mutation in four of the five carcinomas. LOH at 17p was not seen in polyps or carcinomas; immunohistochemistry showed expression of p53 in one carcinoma and focal expression in three polyps. At subsequent sequence analysis, no p53 mutation was found. One carcinoma had an activating K-ras codon 12 mutation and another carcinoma showed 18q LOH; however, no loss of Smad4 expression was seen. CONCLUSIONS: These results provide further evidence that STK11/LKB1 acts as a tumour suppressor gene, and may be involved in the early stages of PJS tumorigenesis. Further research is needed to see whether LOH in PJS polyps could be used as a biomarker to predict cancer. Differences in molecular genetic alterations noted between the adenoma-carcinoma sequence and PJS related tumours suggest the presence of a distinct pathway of carcinogenesis.

AMP-Activated Protein Kinase Kinases↗
PubMed2006

Tobacco smoking and colorectal hyperplastic and adenomatous polyps.

Colorectal adenomas and possibly some hyperplastic polyps are precursors of colorectal cancer. Tobacco use is associated in epidemiologic studies with these polyps, although links between smoking and colorectal cancer are less consistent. To characterize the role of tobacco in early colorectal carcinogenesis, we compared tobacco use among 4,383 subjects with histologically verified benign (hyperplastic or adenomatous) polyps of the distal colon (descending colon, sigmoid, and rectum) with tobacco use among 33,667 subjects who were endoscopy negative for distal colon tumors, in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Trial, a randomized trial of flexible sigmoidoscopy. Risks, estimated by the odds ratio (OR), associated with current cigarette use were OR = 4.4 [95% confidence interval (95% CI), 3.7-5.2] for hyperplastic polyps only, OR = 1.8 (95% CI, 1.5-2.1) for adenomas only, and OR = 6.2 (95% CI, 4.7-8.3) for subjects with both hyperplastic and adenomatous polyps concurrently. Effects were weaker among ex smokers; the smoking-associated ORs remained consistently higher for hyperplastic polyps. This pattern was also seen in relation to cigarettes smoked per day, smoking duration, and pack-years. Tobacco-associated risks for multiple polyps were also stronger when hyperplastic disease was involved. In conclusion, tobacco use, particularly recent use, increases risk for both adenomatous and hyperplastic polyps, but the risks are substantially greater for hyperplastic lesions.

Adenomatous Polyposis Coli↗
PubMed2003

Somatic mutations in familial adenomatous polyps. Nuclear translocation of beta-catenin requires more than biallelic APC inactivation.

Germline mutations of the APC gene cause familial adenomatous polyposis coli (FAP). APC inactivation results in dysregulation of wnt/wingless signaling and contributes to chromosomal instability in vitro. To investigate somatic alterations that follow a known germline mutation and contribute to the transition from normal to neoplastic mucosa, we studied 10 adenomatous polyps from a 27-year-old patient with an APC germline mutation at codon 554. Chromosomal imbalances were analyzed by comparative genomic hybridization; APC and K-ras were screened for somatic mutations. Before DNA analysis, the polyps were bisected to compare the genetic alterations with the corresponding immunohistologic phenotype of beta-catenin, a proto-oncogene product degraded by the APC tumor suppressor. Gains at chromosome 20 were the most frequent chromosomal alterations (6 polyps). Losses were found predominantly at chromosome 4q (3 polyps). A K-ras mutation was seen in 1 polyp, while all polyps displayed somatic intragenic APC mutations. Comparative immunohistologic analysis revealed strong membranous staining for beta-catenin in all adenomatous polyps, but only 1 adenoma showed nuclear accumulation. Our results suggest chromosomal aberrations contribute early to the progression of adenomatous polyps after biallelic APC inactivation. APC inactivation itself is insufficient for immunohistochemically detectable nuclear translocation of beta-catenin.

Adenomatous Polyposis Coli↗
PubMed1998

Close correlation between telomerase expression and adenomatous polyp progression in multistep colorectal carcinogenesis.

To investigate the role of telomerase in the multistep colorectal carcinogenesis, we examined telomerase activity in 31 adenomatous polyps and 22 paired cancer-normal mucosa specimens from non-hereditary nonpolyposis colorectal cancer patients. Telomerase activity was detected in 18% of normal mucosa, 16% of small (<1.0 cm) polyps, 20% of intermediate polyps, 71% of large (>2.0 cm) polyps, and 96% of adenocarcinoma samples (P for trend, <0.0001). High-level enzyme activities were seen in none of the normal mucosa, 5% of small polyps, 20% of intermediate polyps, 43% of large polyps, and 73% of adenocarcinoma samples (P for trend, <0.0001). These data indicate telomerase reactivation occurs with adenomatous polyp progression in multistep colorectal carcinogenesis.

Adenomatous Polyposis Coli↗
PubMed1990

Natural history of colorectal polyps and the effect of polypectomy on occurrence of subsequent cancer.

To elucidate the natural history of colorectal polyps and to observe the influence of endoscopic polypectomy on the incidence of colorectal cancer, we conducted a retrospective cohort study of all patients who had undergone colonoscopic examination at the Center for Adult Diseases, Osaka, between April 1974 and December 1985. The study subjects consisted of a control group (760 non-polyp patients) and a polyp group (648 polyp patients, including 136 treated by polypectomy at the initial examination). These subjects were followed up until the end of 1987 by record linkage with the Osaka Cancer Registry's file to observe the occurrence of colorectal cancer. The O/E (observed/expected numbers derived from the general population) was 5.1 (95% confidence interval = 2.5-9.4) and 1.0 (0.1-3.6) for the polyp and control group, respectively. When subjects in the polyp group were categorized into polypectomy and non-polypectomy sub-groups, the O/E was 2.3 (0.1-12.6) and 8.0 (3.4-15.8) respectively. The relative risk of undergoing polypectomy to developing subsequent cancer was estimated at 0.3 (0.1-2.1). These results suggest an increased risk of developing cancer among polyp patients and the possibility of prophylactic effect of polypectomy against subsequent cancer. A large-scale and long-term follow-up study is required to confirm these findings.

Age Factors↗
PubMed1990

Crypt alterations and collagen deposition in hyperplastic polyps of colorectum.

In order to investigate the nature of hyperplastic polyps in the colorectum, 44 longitudinally sectioned crypts from biopsied polyps were analyzed morphometrically and compared with 81 control crypts. Although the crypts in hyperplastic polyps were longer and wider, containing more cells, their cell density was less, particularly in the serrated epithelium. In these crypts, both the tall and short epithelial cells contained cytoplasmic vacuoles, even in the surface epithelium. These cells exhibited increased expression of carcinoembryonic antigen. The subepithelial collagen table was of similar thickness in the polyp and control colonic mucosa, but it extended down along the cryptal wall to a greater depth in the polyp. These and other data indicate an aberrant differentiation of cryptal epithelial cells in the polyp. On upward migration to the surface, these cells appeared to undergo an arrested maturational process. Hence, the hyperplastic polyp may be considered a disease of epithelial cell differentiation.

Biopsy↗
PubMed1993

Clinical significance of diminutive polyps of the rectum and sigmoid colon.

A retrospective review of 637 consecutive colonoscopies with polypectomy in 526 patients was performed to determine the association of small polyps of the rectum and sigmoid colon with more proximal colonic neoplasms. All colonic polyps were proximal to the sigmoid colon in 117 procedures. Proximal neoplasms were found in 32 percent of patients with a single polyp in the rectum or sigmoid colon. The incidence increased to 83 percent for those with three or more polyps. The occurrence of proximal colonic neoplasms was not affected by the size or histologic type of the rectosigmoid polyps. These findings would suggest that total colonic evaluation be considered in all patients with a polyp in the rectum or sigmoid colon regardless of the size or histologic type of the polyp.

Adenoma↗
PubMed1995

Management and outcome of patients with invasive carcinoma arising in colorectal polyps.

BACKGROUND & AIMS: Treatment for invasive adenocarcinoma in colorectal polyps (malignant polyps) is controversial. The aim of this study was to evaluate our institutional treatment strategy for malignant polyps. METHODS: Malignant polyps were designated as having favorable histology (grade I or II carcinoma with at least a 2-mm free margin) or unfavorable histology (grade III invasive adenocarcinoma, invasive adenocarcinoma with an unassessable margin, or a margin of < 2 mm). Malignant polyps with favorable histology were considered treated adequately by endoscopic polypectomy, whereas further therapy was recommended for malignant polyps with unfavorable histology. Recurrence, residual adenocarcinoma in a follow-up resection specimen, or metastasis during follow-up were considered adverse outcomes. RESULTS: Of the 47 patients identified, 17 (36%) had favorable histology. Sixteen patients (94%) were treated with polypectomy alone. None had an adverse outcome (median follow-up, 70 months). Thirty patients (64%) had unfavorable histology, and 21 patients (70%) underwent colectomy. Five patients underwent radiation therapy alone. Four patients underwent no additional therapy. Ten of 30 patients with unfavorable histology had adverse outcomes that differed significantly from the favorable histology group (P = 0.03). CONCLUSIONS: Endoscopic polypectomy alone is adequate therapy for malignant polyps with favorable histology.

Adenocarcinoma↗
PubMed1988

Serum cholesterol and colorectal polyps.

Colorectal cancer and hypocholesterolemia have recently been associated, and colorectal polyps have a known relationship with colorectal cancer. In order to establish further evidence regarding the nature of the serum cholesterol-colorectal cancer relationship, this study investigated the hypothesis that men with colorectal polyps would have lower serum cholesterol levels than men without polyps. Of the 1380 men screened by sigmoidoscopy for colorectal polyps, 246 had at least one polyp. The men with polyps were older than those without, and also had higher cholesterol levels, but after controlling for age, there were no serum cholesterol differences. These data suggest that low serum cholesterol is not etiologically linked to cancer. Analyses of potentially confounding variables showed smoking to be strongly related to the presence of polyps.

Adult↗
PubMed2004

A novel endoscopic device for retrieval of polyps resected from the colon and rectum.

BACKGROUND: Retrieval of polyps resected from the colorectum is time consuming, despite the availability of various devices, such as grasping forceps, nets, and suction traps, for this purpose. A novel device for retrieval of polyps was developed and tested. METHODS: Patients with polyp(s) less than or equal to 6 mm in diameter were included in this study. The effectiveness of the device for polyp retrieval was evaluated. OBSERVATIONS: In total, 180 of 184 polyps were retrieved from 100 patients. Four polyp specimens (2.2%) were lost after polypectomy. None of the retrieved specimens were damaged. All retrieved polyps could be assessed histopathologically, and a definitive diagnosis was made. CONCLUSIONS: The newly developed device proved to be reliable when used in clinical practice.

Adult↗
PubMed1981

A canine model of gastric and colonic polyps.

Polyps were produced in the canine stomach and colon by a surgical technique. In a total of 18 dogs 26 polyps were produced in the stomach or colon. Twenty of the 26 polyps were viable when endoscopically and microscopically examined. Polyps of approximately 1 cm in diameter and 3 to 4 cm in length can be produced without sloughing. The gross and microscopic characteristics of the canine polyp are quite similar to the human condition. Obviously the adenomatous tissue of the polyp head was not reproduced, but this area is not generally cut during polypectomy. The surgical produced polyps appear to be useful as a model to study the effects of electrosurgical cutting and for training in the technique of polypectomy.

Animals↗
PubMedDate not supplied

Tiny snares prove safe and effective for removal of diminutive colorectal polyps.

The efficacy of two new tiny snares has been evaluated for removal of diminutive (7 mm or less) colorectal polyps. The small size of the snares facilitates direct placement over a polyp, after which resection can be performed using monopolar current. Data were prospectively collected on 183 polyps, 2 to 7 mm in diameter, encountered in 90 patients. Polyp diameter, location relative to the splenic flexure, and histologic characteristics were noted, as were retrieval rate and complications. Ninety-four percent of the polyps could be removed with a tiny snare, and 88% of these were recovered. Forty percent of the polyps were located proximal to the splenic flexure, and 69% were neoplastic. The only complication was major hemorrhage in 1 patient (0.5%), in whom snare polypectomy without current application was used. Tiny snares can effectively and safely be used to remove diminutive colorectal polyps, and they may make "hot biopsy" forceps obsolete.

Adenoma↗