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Predictive value of a diagnosis of colonic polyp on the double-contrast barium enema.

The positive predictive value of a diagnosis of colonic polyp on the double-contrast barium enema was determined by analyzing 160 polypoid lesions reported in 105 patients. Of the 160 polyps, 139 were confirmed by endoscopy, surgery, or repeat barium enema for a positive predictive value of 87%. Twenty-one lesions were not confirmed despite repeat endoscopy, repeat barium enema, review of the original study, or surgery, giving a false positive rate of 13%. The individual false positive error rates of 5 radiologists ranged from 8% to 26%. False positive errors were due to stool, diverticula, air bubbles, misinterpretation of the ileocecal valve, and haustration. Many of the false positive errors appeared to have been avoidable if the original examination had been more meticulously interpreted.

Adult↗

Colonic polyps of acromegalic patients are not associated with mutations of the peroxisome proliferator activated receptor gamma gene.

Peroxisome proliferator activated receptor (PPAR)gamma plays a pivotal role in regulating adipocyte differentiation and metabolism, but also has an antiproliferative effect in several tissues, including colonic mucosa, where it is highly expressed. Loss-of-function mutations have been reported in about 10% of sporadic primary colon cancer. Acromegalic patients have an increased prevalence of colonic neoplasms and lower PPARgamma levels in the colonic mucosa. Thus, PPARgamma may act as a tumor suppressor gene, and its reduced expression or loss-of-function mutations may contribute to tumorigenesis. In this study the expression and mutations of the PPARgamma gene in the colonic polyps and mucosa outside polyps were investigated in 10 acromegalic and 17 non-acromegalic patients. PPARgamma expression was evaluated by RT-PCR. PPARgamma was expressed in each sample, but expression appeared to be lower in polyps than in mucosa outside polyps from either acromegalic or non-acromegalic patients. All exons of the PPARgamma gene were directly sequenced after PCR amplification: no mutations were found either in acromegalic or in non-acromegalic patients. In conclusion, the results of this preliminary study suggest that the lower expression of PPARgamma rather than somatic mutations of this gene is involved in colonic tumorigenesis.

Acromegaly↗

Analysis of cyclin D1 and CDK expression in colonic polyps containing neoplastic foci: a study of proteins extracted from paraffin sections.

Overexpression or amplification of G1 cyclins has been demonstrated in various types of human cancers. Overexpression of cyclin D1, an accelerator of cell cycle, is thought to be an early event in colonic multistage carcinogenesis, but its expression at transformation from benign to neoplastic foci is not clear. We analyzed the expression of cyclin D1 and its catalystic partner CDK4 in colon polyps containing neoplastic foci. For direct comparison of the expression in adenomatous tissues and neoplastic foci, proteins in adequate amounts were extracted from paraffin embedded sections. Western blot and densitometry analyses showed that cyclin D1 expression was 2.3-times and 2.5-times higher in adenomatous tissues and neoplastic foci, compared with normal colonic mucosa. In contrast, the levels of CDK4 and CDK2 expression were only modestly increased in adenomatous tissues but significantly higher in neoplastic foci, relative to normal mucosa. Expression of PCNA, a cell proliferation marker, increased from normal mucosa to adenoma to focal cancer. Our findings suggest that overexpression of cyclin D1 may be associated with high proliferative activity in adenomatous tissues and that concurrent high expression of cyclin D1 and CDK4 may further perturb cell cycle progression and play a pivotal role in colonic carcinogenesis.

Adenoma↗

Metastatic malignant mesothelioma presenting as colonic polyps.

A 66-year-old male engineer diagnosed with malignant pleural mesothelioma 4 years previously had thoracotomy, radiotherapy, and chemotherapy. He was followed regularly with chest computed tomography (CT) scan and had been asymptomatic. During one of his physical examinations, routine sigmoidoscopy showed incidental colonic polyps which were biopsied. Subsequently, recurrence of pleural mesothelioma and peritoneal involvement by mesothelioma was documented. Two of the polyps showed metastatic malignant mesothelioma in the lamina propia which strongly resembled adenocarcinoma histologically causing difficulty in making definitive diagnosis. Review of the literature disclosed no previously documented similar occurrence. This case shows the importance of clinical history and ancillary laboratory procedures such as immunohistochemistry and electron microscopy to avoid diagnostic pitfalls.

Adenocarcinoma↗

Diminutive colonic polyps--clinical significance and management.

Of 300 diminutive polyps (up to 5 mm) found at colonoscopy, 114 were neoplastic (37 per cent) and thus possible precursors of carcinoma. This suggests that all colonic polyps, regardless of size, should if possible be extirpated or coagulated. As polyps of this small size often escape detection roentgenologically, especially by conventional technique, colonoscopy should be extended to involve the entire colon. This is because diminutive polyps, especially of neoplastic type, are common also in the proximal part of the colon.

Adult↗

Radiographic magnification of colon polyps.

Radiographic magnification was evaluated on conventional and remote control machinery using a phantom with steel rods positioned at different levels. Depending on the rod-film distance, the range of magnification was 8-47% on remote control and conventional overhead films and 11-82% on conventional fluoroscopic spot-films. Extrapolation to the colon based on cross-sectional anatomic correlation showed a 14-27% variation in the radiographic magnification depending on the machinery used, the segment of the colon considered, and the position of the patient. This implies that substantial inaccuracy in the measurement of colonic polyps is common by barium enema examination, particularly when a conventional fluoroscope is used.

Colonic Polyps↗

Long-term survival after treatment of malignant colonic polyps.

PURPOSE: This study was designed to evaluate the long-term outcome and survival of patients treated for malignant colonic polyps. METHODS: A retrospective review of 15,975 cases of colonoscopies with 8,685 endoscopic polypectomies performed between 1972 and 1990 was undertaken. In 65 patients, the polypectomy specimens contained invasive carcinoma. Six patients were excluded (follow-up, <6 months). Polyp data, operative findings, and follow-up on the remaining 59 patients were recorded. RESULTS: Malignant polyps were found in 35 males and 24 females who had an average age of 64 (range, 39-81) years. Follow-up ranged from 12 to 202 (mean, 90) months. Tumor differentiation was poor in one and well or moderately differentiated in 58 patients. Positive or indeterminate margins were found in 13 patients. Thirty-seven (63 percent) patients were managed with polypectomy and surveillance. Four of these (with rectal tumors) also had an additional local excision for questionable margins. One recurrence was noted in a patient who refused surgery, which was recommended because of indeterminate margins. Twenty-two patients (37 percent) underwent colectomy. Indications included Haggitt Level 3 or 4 invasion (19), inadequate margins (7), patient preference (1), and poor differentiation (1). Residual disease was found in colectomy specimens of three patients (14 percent). There were no cancer-related deaths in either treatment group. Life table analysis demonstrated a five-year survival of 82 percent for the colectomy group and 95 percent for the polypectomy group (P = 0.15). CONCLUSION: Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Adult↗

An appraisal of endoscopic removal of malignant colonic polyps.

The issue of whether patients who have invasive carcinoma in an otherwise benign polyp should undergo surgical resection of that bowel segment is controversial. We examined the records of 83 patients with such polyps that were removed endoscopically between 1978 and 1981. After exclusion of 18 patients from the study for various reasons, our study group consisted of 65 patients who had undergone complete endoscopic removal of 69 polyps that contained a malignant process. Carcinoma in situ was found in 34 polyps, and 3 patients with such polyps had a recurrent malignant lesion of the same degree. These recurrent tumors were treated successfully by aggressive endoscopic removal. Seventeen polyps that contained invasive carcinoma were treated endoscopically without resection, and two patients in this group subsequently had recurrent carcinoma at the site of the original polyp. These recurrent lesions were resected, and neither patient had evidence of nodal metastasis. Of the 18 patients who underwent immediate resection of invasive carcinoma, 2 had residual carcinoma at the time of the resection, although no lymph node metastasis was found. We conclude that colonic polyps with carcinoma in situ can be treated safely with complete endoscopic removal. Invasive carcinoma in a polyp can be treated safely with complete polypectomy, and immediate resection may not be necessary. This group of patients, however, should undergo thorough follow-up studies and periodic endoscopic reexamination.

Adenocarcinoma↗

Endoclip-assisted resection of large pedunculated colon polyps.

BACKGROUND: Large pedunculated colorectal polyps are often difficult to remove endoscopically. METHODS: Four patients with giant pedunculated polyps (>3 cm) underwent an endoscopic procedure in which the polyp stalk was ligated with multiple clips and resected with a needle-knife papillotome. RESULTS: No complications occurred either during or immediately after the procedure. Mean size of the resected polyps was 4.8 +/- 1.2 cm (range 3 to 6 cm). Mean time for the entire procedure was 31 +/- 5 minutes (range 25 to 45). No bleeding was found after a mean follow-up period of 4.3 +/- 1.1 months (range 3 to 6 months). CONCLUSIONS: Although technical refinements are necessary to make the procedure easier and faster, this approach might represent the only option for selected patients who would otherwise need surgical resection of large pedunculated colonic polyps.

Colonic Polyps↗

[Multiple adenomatous papillary colonic polyps in a family with frequent cases of stomach carcinoma--a new phenotype of familial colonic polyposis].

A kindred of "minor adenomatous polyposis" associated with a high incidence of gastric cancer is described. Five out of 14 mainly asymptomatic individuals in 2 generations of kindred examined clinically, by panendoscopy and coloscopy exhibited multiple polyps of colon or/and stomach and jejunum. Single or multiple papillary adenomas were detected mainly in the right or middle colon (3 times or in the jejunum (once). Hyperplastic polyps were found in the stomach (3 times) and in the colon (twice of these 5 individuals. Our findings suggest that "minor adenomatous polyposis" associated with gastric cancer may represent another, hitherto unrecognized, phenotype of familial multiple polyposis.

Colonic Diseases↗