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Cytomegalovirus colitis in acquired immunodeficiency syndrome: a clinical and endoscopic study.

BACKGROUND: Cytomegalovirus colitis is an important complication of the acquired immunodeficiency syndrome (AIDS), although the clinical and colonoscopic manifestations of this disease have not been systematically characterized. METHODS: Patients with AIDS and cytomegalovirus colitis were prospectively identified at two medical centers. The diagnosis of cytomegalovirus disease was based on established endoscopic and histologic criteria. At the time of sigmoidoscopic and/or colonoscopic examination, clinical features were recorded; the location, size, and appearance of all endoscopic abnormalities were documented; and multiple biopsies of any lesions were performed. RESULTS: Fifty-six patients were studied. The majority of the patients were homosexual men with severe immunodeficiency (median CD4 lymphocyte count 15/mm3, range 1 to 294/mm3). Chronic diarrhea and abdominal pain were the most frequent clinical manifestations, seen in 45 (80%) and 28 (50%) patients, respectively. Five patients (9%) presented with lower gastrointestinal hemorrhage, three of whom had no antecedent history of diarrhea. The colonoscopic abnormalities could be categorized into three main groups: colitis associated with ulcer (39%), ulceration alone (38%), or colitis alone (20%). Subepithelial hemorrhage was a prominent endoscopic manifestation of disease. Of the 31 patients undergoing colonoscopy to the cecum, in four (13%) endoscopic evidence of disease was limited to the colon proximal to the splenic flexure. CONCLUSIONS: Cytomegalovirus colitis in AIDS appears to have variable but stereotypical clinical and colonoscopic manifestations. Distal colitis associated with ulceration is the most common colonoscopic pattern.

Acquired Immunodeficiency Syndrome↗

Surveillance colonoscopy or chemoprevention with COX-2 inhibitors in average-risk post-polypectomy patients: a decision analysis.

OBJECTIVES: Clinical trials are currently underway evaluating the efficacy of COX-2 inhibitors in decreasing the incidence of adenomas and colorectal carcinoma in 'average' risk individuals. AIM: To use decision analysis to compare the cost-effectiveness of celecoxib to surveillance colonoscopy in 'average' risk patients who had undergone prior adenoma resection. METHODS: A model of the natural history of adenomas after endoscopic polypectomy was constructed using probabilities from the literature. Cost estimates were obtained from available Medicare reimbursement rates and supplemented by the literature. Three strategies were evaluated: (i) no surveillance; (ii) colonoscopic surveillance; and (iii) celecoxib chemoprevention. We compared total costs and performed cost-effectiveness analysis between these strategies. The outcome measures were years of life saved and 'high-grade' adenoma prevented. Sensitivity analyses were performed on selected variables. RESULTS: Our base-case analysis assumed a 50% risk reduction in the incidence of adenomas among patients using celecoxib. No surveillance was associated with a cost of $1014 per patient, and colonoscopic surveillance with a cost of $1572 per patient, whereas celecoxib use was associated with a total cost of $11,503. Ten years after the index colonoscopy, 15% of patients in the no surveillance strategy developed 'high-grade' lesions compared to 13% of patients in the colonoscopic surveillance group and 6% in the celecoxib group. There was a small gain in years of life saved (0.006) favouring celecoxib over colonoscopic surveillance. The incremental cost-effectiveness ratio of celecoxib vs. colonoscopy was $141 871 per 'high-grade' adenoma prevented and $1,715,199 per year of life saved. The most important variables in determining the cost-effectiveness of celecoxib were its cost and its efficacy. CONCLUSION: Chemoprevention with COX-2 inhibitors in 'average-risk' postpolypectomy patients is a more expensive strategy compared to colonoscopic surveillance.

Adenoma↗

Evaluation of a new three-dimensional magnetic imaging system for use during colonoscopy.

BACKGROUND AND STUDY AIMS: A prototype magnetic imaging system (Scope Guide, Olympus Optical Co., Ltd.) provides a new facility for continuous viewing on a monitor of the position of the colonoscope during examination, without exposing patients or medical staff to radiation. The aim of this prospective study was to compare this magnetic imaging system with routine colonoscopy, including fluoroscopy. The study parameters were the detection of loops, the location of the endoscope tip at defined positions, the insertion time, and the premedication rate. MATERIALS AND METHODS: In the first part of the study, 133 consecutive patients were examined - 64 using an integrated three-dimensional colonoscope and 69 with the three-dimensional probe inserted into the biopsy channel of a routine video colonoscope. Fluoroscopy was used in all investigations for comparison at defined anatomical points and loops, and pathological findings and defined anatomic structures were documented using a laser printer both for three-dimensional colonoscopy and fluoroscopy. In the second part of the study, 25 further patients underwent colonoscopy with a modified prototype, now exclusively using the integrated three-dimensional colonoscope. RESULTS: The total time for insertion and the premedication rate did not differ from those of routine colonoscopies with fluoroscopy available. Precise detection of loops was observed in the first study in 79 - 100 % of cases in comparison with fluoroscopy. Precise localization of the endoscopic tip improved from 30 % in the first part of the study to 80 % in part 2. CONCLUSION: Using magnetic three-dimensional imaging systems, the position of the colonoscope, the detection and observation of loops during straightening, and localization of pathological findings can be accurately achieved. Modification of the prototype led to satisfactory improvement in all parameters tested.

Colonoscopy↗

Validity of early colonoscopy for the treatment of adenomas missed by initial endoscopic examination.

OBJECTIVE: To determine whether the features of adenomas identified in a first endoscopic examination may predict the presence of polyps with advanced pathological features that may have gone unnoticed and whether early colonoscopy may benefit these patients. MATERIAL AND METHODS: We examined 133 patients with diagnosis of colonic adenomas who had undergone complete colonoscopy and endoscopic polypectomy. All of them underwent colonoscopic follow-up at 3 years. Seventy nine patients underwent colonoscopic follow-up both at 6 months and at 3 years, while 54 patients underwent just colonoscopic follow-up at 3 years and 47 just at 6 months. RESULTS: Fifteen per cent of the patients analyzed developed polyps with pathological features after 6 months. The size and histological analysis of the polyps detected in the initial colonoscopic examination did not affect these results (p < 0.05). The number of polyps was statistically significant: patients with 3 or more polyps in the initial colonoscopic examination presented more polyps with pathological features after six months (25.8 versus 5.8%, p = 0002). This follow-up examination at 3 years did not reveal a higher occurrence of polyps with pathological features in any of the two groups of patients, namely, those who had undergone early colonoscopy and those who had not. CONCLUSIONS: Patients with multiple polyps have greater probability of developing synchronous polyps with some pathological features which may have gone unnoticed. Since early examination has not shown to provide a benefit for these patients, the first follow-up colonoscopy should be performed at 3 years, particularly if the initial colonoscopy is negative.

Adenoma↗

Large colorectal polyps: colonoscopy, pathology, and management.

Between 1984 and 1987, we reviewed all large (greater than or equal to 3.0 cm) colorectal polyps to determine the efficacy of colonoscopic polypectomy from both an oncologic and technical viewpoint. Forty-eight polyps greater than or equal to 3.0 cm were identified in 46 patients. Twenty polyps were entirely benign, 20 polyps contained noninvasive carcinoma, and invasive carcinoma was present in eight polyps. Four of the invasive cancers were associated with residual adenoma; the remaining four were polypoid carcinomas. Among the eight cases of invasive carcinoma, four had tumors that did not extend through the submucosa. Invasive cancer was more prevalent in left-side sessile lesions but was absent in all 10 right-sided polyps. Thirty-two polyps were removed by colonoscopic polypectomy. Four patients required colectomy after polypectomy for the following reasons: incomplete excision (N = 1), presence of invasive carcinoma at the resection margin (N = 1), and inability to define the level of carcinoma on pathologic examination (N = 2). Two polyps with cancer confined to the submucosa were successfully excised colonoscopically. Complications of polypectomy included three cases of minor hemorrhage. Sixteen polyps (the majority located in the right colon) were removed by primary surgical colectomy. We conclude that colonoscopic polypectomy is oncologically and technically successful for most large colorectal polyps. A minority of large polyps require colectomy because of incomplete removal or the presence of invasive cancer that is not curable with colonoscopic excision.

Adenoma↗

The Cath-Cam: a new concept in colonoscopy.

BACKGROUND: Guidewires and catheters exert less force on the gut wall than an endoscope. OBJECTIVE: To develop a guidewire-assisted device for colonoscopy. METHODS: A light-weight flexible catheter illuminated with light-emitting diodes was designed to carry an ultraslim high-resolution videoendoscope of 3 mm. Tip bend stiffness was 5 times less than a colonoscope. Hinged guidewires were passed, folded, through the accessory channel. A loop could be rapidly formed to explore the lumen. RESULTS: The catheter followed curves of excised pig colon and exerted significantly less force on the colon wall than a colonoscope (mean 1.6 +/- 0.23 N vs 3.0 +/- 0.37 N, P < .05; bend-radius, 80 mm). Survival studies in pigs showed that the guidewire loop could be advanced under visual control and the Cath-Cam could be advanced by using much less force than the colonoscope. CONCLUSIONS: A catheter-based colonoscope with a miniature video imager reduced the force required for successful colonoscopy in pigs.

Animals↗

Salmonella newport infections transmitted by fiberoptic colonoscopy.

During a 2-week period following the colonoscopy and biopsy of a patient with acute Salmonella newport gastroenteritis, S. newport was recovered from colonic aspirates or fecal specimens of eight of 28 patients from whom specimens were cultured during or after colonoscopy. Two of the eight persons from whom S. newport was isolated developed acute gastroenteritis, two had asymptomatic infections, and four had positive aspirates collected through a colonoscope but did not become infected. Although S. newport was never recovered from the four colonoscopes used during the outbreak, cultures of one of the colonic biopsy forceps grew S. newport. Contamination of the equipment most likely occurred during colonoscopy of the index patient. Inadequate disinfection of the equipment allowed the organism to survive and possibly to cross-contaminate other colonoscopes, and the organism was then transmitted to other patients by use of the contaminated colonoscopes or the contaminated biopsy forceps. Implemented control measures terminated the outbreak.

Adult↗

Natural bioburden levels detected on flexible gastrointestinal endoscopes after clinical use and manual cleaning.

BACKGROUND: Colonoscopes present a special bacterial decontamination challenge because the colon has a large and diverse microbial population. METHODS: Bioburden of colonoscope insertion tube surfaces and suction channels were determined after use and after manual cleaning. RESULTS: After use bioburden in suction channels averaged 7.0 x 10(9) colony-forming units (cfu). Cleaning reduced this level to 1.3 x 10(5). Cleaning of tube surfaces reduced the after-use bioburden from a level of 5.1 x 10(5) to 2.2 x 10(4) cfu. Gram-negative rods accounted for approximately 99% of the bioburden within the suction channel after use and after cleaning. After use flora were predominantly Escherichia coli and Bacteroides. The flora shifted to waterborne Pseudomonas organisms, and other members of the family Enterobacteriaceae after cleaning. Gram-positive bacteria were the primary isolates from the device surfaces both after use (56%) and after cleaning (47%). Because gram-positive cocci and diphtheroids are a part of the normal microbiota of the skin, these bacteria may have been introduced by the hospital environment or by handling. CONCLUSIONS: After the cleaning of in-use colonoscopes, fewer than 10(6) vegetative bacteria could be recovered. This value is several logs lower than some previous estimates. This finding may be useful in the formulation of sterilization and disinfection cycles. Microflora from the colonoscopes indicated that the cleaning process introduced waterborne and enteric microorganisms, which highlights the importance of sanitation in the device reprocessing area.

Bacteria, Aerobic↗

Worst-case soiling levels for patient-used flexible endoscopes before and after cleaning.

BACKGROUND: The soiling levels of patient-used narrow-lumened flexible endoscopes were assessed for bronchoscopes, duodenoscopes, and colonoscopes. The effect of cleaning on the soil composition and concentration was evaluated. DESIGN: Suction channels from 10 each of bronchoscopes, duodenoscopes used for endoscopic retrograde cholangiopancreatography, and colonoscopes were assessed immediately after patient use for the levels of bilirubin, hemoglobin, protein, sodium ion, carbohydrate, endotoxin, and viable bacteria. Another 10 suction channels of each type of endoscope were evaluated for the same components after routine cleaning but before processing by high-level disinfection or sterilization for subsequent clinical use. RESULTS: Recognizing that only soluble components could be quantified, the worst-case soil levels in the suction channels (the average surface area of these channels was 45.6 cm(2), 149.8 cm,(2) and 192.0 cm(2) for bronchoscopes, duodenoscopes, and colonoscopes, respectively) were protein 115 microg/cm(2), sodium ion 7.4 micromol/cm(2), hemoglobin 85 microg/cm(2), bilirubin 299 nmol/cm(2), carbohydrate 29.1 microg/cm(2), endotoxin 9852 endotoxin units/cm(2), and bacteria 7.1 (log(10)) colony-forming units (CFU)/cm(2). Colonoscopes had 4 to 5 times greater soiling on average compared with the other endoscope types. Routine cleaning reduced the levels of bilirubin to below the limits of detection for all endoscopes evaluated (limits of detection were <1 nmol/mL). After cleaning, residual hemoglobin was detectable in bronchoscopes only. After cleaning, the levels of protein, endotoxin, and sodium ion all were reduced fivefold to tenfold for all types of endoscopes. Carbohydrate was reduced to lower than the limit of detection for all endoscopes after cleaning, except the duodenoscopes. The average load of viable bacteria was reduced from 3 log(10) to 5 log(10) CFU/cm(2) (which represents 5.9-9.5 log(10) CFU/endoscope channel) after patient use to approximately 2 log(10) CFU/cm(2) (which represents 3.2-5.3 log(10) CFU/endoscope channel) after cleaning. CONCLUSIONS: These data demonstrated that cleaning effectively reduced or eliminated many components of soil, but a substantial amount of viable bacteria and protein remained. Hemoglobin levels in before samples indicated that blood was not present in high concentrations in the suction channels of the majority of flexible endoscope samples. Soil that mimics the worst-case composition from patient-used endoscopes would be ideal for simulated-use studies for such medical devices.

Bronchoscopes↗

Technical considerations and patient comfort in total colonoscopy with and without a transparent cap: initial experiences from a pilot study.

BACKGROUND AND STUDY AIMS: Even though colonoscopy was introduced 30 years ago, endoscopists still leave a small percentage of the colonic mucosal surface unexamined because of the limitations of the procedure, so there is still room for technical improvements. The aim of this pilot study was to test the feasibility of attaching a transparent cap to the tip of the colonoscope, partly to gather basic data and experience for planning a larger randomized study, and partly to evaluate any technical advantages or disadvantages, and also to appraise the patients' experiences. PATIENTS AND METHODS: In 50 consecutive patients examined by a single experienced endoscopist, a prospective pilot study was carried out comparing the use of a colonoscope fitted with a transparent cap (in half of the colonoscopies) with the use of an ordinary colonoscope without a cap (in the remaining 25 patients). The following parameters were recorded: indication for colonoscopy, time to reach the cecum, total time for the colonoscopy, findings, diagnosis, type of colonoscopy (diagnostic or therapeutic, partial or total, ileal intubation), the amount of analgesia and sedation given during the endoscopy, and complications. At the end of the examination and also before leaving the hospital, the patients were asked by a nurse to estimate pain experienced during the colonoscopy, using a visual analogue scale. RESULTS: The time for the procedure, the ability to perform a complete colonoscopy (including ileal intubation when it was medically relevant), and the complication rate turned out to be similar in both groups. There were no differences between the amounts of analgesia and sedation given during the endoscopy or between the patients' estimations of the pain experienced. CONCLUSIONS: The time to reach the cecum and the total time for the colonoscopy is the same with or without the cap, which is well tolerated by patients. Using the cap greatly facilitates the possibility of finding small polyps behind folds in the colon, because the folds can be straightened, thereby improving the view, although in this small pilot study it could not be proven that the number of polyps found was greater using a cap-fitted colonoscope.

Adult↗

Novel three-channel and three-slit stiffening tube for total colonoscopy.

BACKGROUND AND STUDY AIMS: Because of the recent marked reduction in the diameter of colonoscopes, existing stiffening tubes require modification of their tips and hardness. The aim of this study was to develop a new stiffening device with a flexible soft tip which closely fitted the colonoscope. It was also designed with three slits, to improve the fit of the stiffening tube itself to the colonoscope and to extend the effective colonoscope length, and equipped with three channels for endoscopic treatment. MATERIALS AND METHODS: The standard stiffening tube which has been used routinely and a novel three-channel, three-slit (TCTS) stiffening tube were employed alternately (in 160 and 161 patients, respectively). The two tubes were compared for severity of pain experienced by patients, ease of intubation, and complications. RESULTS: Among the 160 patients examined with the standard stiffening tube, one (0.63 %) complained of mild anal pain on intubation and intubation was incomplete in two (1.25 %), because of resistance in the rectum and sigmoid colon. Among the 161 patients examined with the TCTS stiffening tube, three patients who presented early in the series (1.86 %) developed mild proctal redness and erosions, but incomplete intubation or serious complications were not recorded. CONCLUSION: The TCTS stiffening tube was as easy to use as the standard stiffening tube, and is considered to be both safe and useful.

Colonic Diseases↗

Usefulness of performing colonoscopy one year after endoscopic polypectomy.

This retrospective study defines a population with neoplastic colonic polyps who have had colonoscopic polypectomy and, in follow-up within one year, a repeat colonoscopic evaluation. The population was broken down into two groups, one group that had polyps at the second examination and one group that did not. This study determined which factor(s) were significant among this population in distinguishing whether new polyps would be found at one year follow-up. The authors found that among the many variables studied, only polyp multiplicity was significant in predicting polyp recurrence. More than one polyp found at index colonoscopy led to a significant chance of having a new polyp after only one year. Also, it was demonstrated that these "new" polyps were unlikely to have been "missed" polyps from the initial colonoscopy. Because of the shifting location, smaller size, and fewer instances of histologic atypia in these polyps compared with those at index examination, the authors believe that polyps found after one year may be assumed to have arisen de novo. Finally, the authors show that a significant number of polyps occur beyond the reach of the flexible sigmoidoscope (approximately 60 cm). The authors recommend that patients who have polyps undergo a colonoscopic examination. When patients are re-evaluated after having colonoscopic neoplastic polypectomy, they should undergo repeat colonoscopy.

Adenoma↗

Dysplasia complicating chronic ulcerative colitis: is immediate colectomy warranted?

PURPOSE: Inflammatory bowel disease surveillance strategies are designed to identify patients at greater than average risk for the development of invasive colonic carcinoma. Colonoscopic detection of mucosal dysplasia is considered the best available surveillance tool. However, the usefulness of dysplasia as a marker for cancer is uncertain. Furthermore, when dysplasia is found some suggest immediate colectomy, whereas others opt for continued surveillance. The aim of this study is to determine whether an association between dysplasia grade and cancer exists in patients with chronic ulcerative colitis, to ascertain the sensitivity, specificity, and positive predictive value of dysplasia as a cancer marker, and to clarify what action to take once dysplasia is discovered. METHODS: The pathology reports of 590 patients who underwent total proctocolectomy or restorative proctocolectomy for chronic ulcerative colitis were reviewed for dysplasia, grade of dysplasia, presence of carcinoma, and tumor stage. One hundred sixty of these patients had undergone colonoscopic examination within the year before surgery. Findings from these studies were also reviewed. RESULTS: Seventy-seven specimens (13.1 percent) contained at least one focus of dysplasia. Invasive cancers were found in 38 specimens (6.4 percent). Cancers were significantly more common among specimens with dysplastic changes (33/77 vs. 5/513; P < 0.001). Specimens with dysplasia of any grade were 36 times more likely to harbor invasive carcinoma. Stage III disease was found in association with indefinite or low-grade dysplasia in 5 of 26 (19.2 percent) of cases. Tumor stage did not correlate with dysplasia grade. Preoperative colonoscopy identified neoplastic changes in 57 (69.5 percent) cases. Dysplasia, cancer or both were missed in 25 cases. Lesions were correctly identified in only 31 (39.7 percent) of cases. Colonoscopically diagnosed dysplasia as a marker for synchronous cancer had a sensitivity of 81 percent and a specificity of 79 percent. The positive predictive value of a finding of preoperative dysplasia of any grade was 50 percent. The positive predictive value of a finding of low-grade dysplasia was 70 percent. CONCLUSIONS: Dysplasia is an unreliable marker for the detection of synchronous carcinoma. However, when dysplasia of any grade is discovered at colonoscopy, the probability of a coexistent carcinoma is relatively high. Colonoscopic evidence of low-grade dysplasia has a higher positive predictive value than either dysplasia associated mass or lesion or high-grade dysplasia. Dysplasia grade does not predict tumor stage. Because advanced cancer can be found in association with dysplastic changes of any grade, confirmed dysplasia of any grade is an indication for colectomy.

Adolescent↗

A comparison of colonoscopy and roentgenography for detecting polypoid lesions of the colon.

This study compares the effectiveness of the roentgen and colonoscopic examination of the colon for detecting polypoid lesions. We evaluated the findings in 64 patients with suspected or known polypoid lesions who received the same colon cleansing regimen for both examinations, and were studied by examiners of similar expertise. As in other studies, the endoscopist had the advantage of knowing the roentgen findings, and the colonoscopic findings were often taken to indicate whether or not a lesion was present. In about half the patients, however, a second roentgen examination, repeat colonoscopy, or surgical specimen provided additional information for scoring. For example, a filling defect of the same size and location on two roentgen examinations, but not demonstrated at colonoscopy was scored as a false negative colonoscopic finding. The study results indicate that 54% of small polyps less than or equal to 0.9 cm in size were missed on roentgen examination, whereas no proven misses for lesions of this size were shown for colonoscopy. This absence of colonoscopic false-negative findings for small polyps, however, may be partially explained by a relative insensitivity of the roentgen method. For larger lesions greater than or equal to 1.0 cm in size the miss-rate for the two examinations was similar: 15% for roentgen examination and 12% for colonoscopy. We conclude: (1) Colonoscopy is a more sensitive method than roentgen examination for detecting small polyps of the colon, and (2) Performance of the two examinations may be comparable for demonstrating lesions 1.0 cm or larger in size.

Colonic Neoplasms↗

Clean sweep of the colon. The use of intraoperative colonoscopy.

Since 1982, intraoperative colonoscopy has been performed on 66 patients. Preoperative intent was to perform a colonoscopic polypectomy during an intra-abdominal procedure in 44 patients, localize lesions that might subsequently lead to either colon resection or colotomy and polyp excision in 13, localize bleeding sites in 4, determine the extent of inflammatory bowel disease in 2, survey the colon in 2 who did not have preoperative colon radiography, and assess bowel viability in 1. Surgery proceeded as planned in 54 patients; however, colonoscopic findings extended the resection to include additional segments of bowel in 4. In four patients, polypectomy or bowel resection was avoided as a result of the colonoscopic findings. Intraoperative colonoscopy was not possible in four patients. No complications were related directly to this procedure. Intraoperative colonoscopy is a useful adjunct for localizing lesions or "clearing" the colon. In some patients, colonoscopic findings may change the extent of resection performed.

Aged↗

Minimally invasive, endoscopically assisted colostomy can be performed without general anesthesia or laparotomy.

PURPOSE: Fecal diversion is frequently required in critically ill patients who may not be able to tolerate a laparotomy. Laparoscopic-assisted and trephine colostomies are alternative methods for colostomy without laparotomy, but require general anesthetic. The objective of this study was to evaluate the possibility of performing fecal diversion with the assistance of a colonoscope and without the additional morbidity of abdominal exploration or general anesthesia. METHODS: Patients were diverted using a colonoscope to identify a site of the sigmoid colon that could easily be approximated to the anterior abdominal wall as confirmed by transillumination of the abdominal wall. A small skin disc was then removed at this location and a loop colostomy was made. The colonoscope was also used as a guide to identify the proximal and distal limbs of the loop colostomy. Four patients were considered to be critically ill and local or regional anesthetic with sedation was used in these patients. RESULTS: A total of 15 patients were reviewed during the past five years. All 15 patients were successfully diverted using minimally invasive techniques with the aid of the colonoscope. Four of these patients were diverted using local or regional anesthetic without complication, thus avoiding the morbidity associated with a general anesthetic in critically ill patients. CONCLUSION: No complications related to this technique were noted in this five-year review. Endoscopically assisted colostomy is an acceptable method for fecal diversion without the need for laparotomy and can be accomplished using a local or regional anesthetic with sedation.

Adult↗

Microscopic colitis in routine colonoscopies.

Lymphocytic colitis (LC) and collagenous colitis (CC), both known as microscopic colitis (MC), are uncommon entities with increasing incidence as more clinicians take biopsies from macroscopically normal colons and as pathologists use more rigorous diagnostic criteria to be confident of the diagnosis. Information on the incidence of this type of colitis is limited and based on reported cases. The purpose of this work is to estimate the incidence of LC and CC in reviewed routine colonoscopies. We reviewed 2815 colonoscopies performed at a tertiary referral center with an open-access service using restricted histological criteria in order to establish the frequency rate of LC and CC in routine colonoscopic biopsy material. Cases suspicious for MC were stained with Masson's trichrome or Congo red stain and immunohistochemically for lymphocytes, where appropriate. Review of routine colonoscopic biopsies showed that MC is underreported in our colonoscopic material. Incidence rates of LC and CC (0.9 and 0.4, respectively) were based on morphological assessment of colonoscopic biopsies using stringent criteria together with clinical data and after differentiation with other lesions which can mimic MC. The 10.2% rate of this type of colitis in patients with chronic watery diarrhea indicates the necessity to consider these lesions in older individuals with diarrhea and normal endoscopical colonic mucosa.

Adult↗

Flat adenomas of the colon.

Twenty-nine flat adenomas of the colon from 18 patients were identified by histologic review of 340 surgically or colonoscopically removed adenomas from 210 patients. All lesions had a radial diameter of 1.0 cm or less. Twelve of 29 flat adenomas (41%) contained high-grade epithelial dysplasia, while only five of 127 polypoid tubular adenomas 1.0 cm in diameter or less (4%) contained high-grade epithelial dysplasia. Nine patients had multiple flat adenomas, and two patients had concurrent flat, ulcerated colonic carcinomas without an identifiable polypoid precursor adenoma. Colonoscopically and grossly, the lesions were described as sessile or flat, slightly raised plaques, which might be easily missed on colonoscopic examination. These findings suggest that flat adenomas may be a subtype of colonic adenomas with a propensity for development of high-grade epithelial dysplasia at a small size. These lesions may be precursors of small, flat, ulcerated colonic carcinomas. Heightened colonoscopic surveillance of patients in whom flat adenomas have been identified may be warranted.

Adenoma↗