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Robotic colonoscopes could potentially provide a comfortable, less painful and safer alternative to standard colonoscopy. Recent exciting developments in this field are pushing the boundaries to what is possible in the future. This article provides a comprehensive review of the current work in robotic colonoscopes including self-propelled, steerable and disposable endoscopes that could be alternatives to standard colonoscopy. We discuss the advantages and disadvantages of these systems currently in development and highlight the technical readiness of each system to help the reader understand where and when such systems may be available for routine clinical use and get an idea of where and in which situation they can best be deployed., Competing Interests: Conflict-of-interest statement: Winters C, Subramanian V and Valdastri P report a grant from Cancer Research UK, during the conduct of the article. Any opinions, findings and conclusions, or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of CRUK., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

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Aim The study aimed to investigate whether narrow-band imaging (NBI) can enhance adenoma detection in patients at high risk for adenomas compared with high-definition white-light endoscopy (WLE). High risk was defined as three or more adenomas at last colonoscopy, history of colorectal cancer and positive faecal occult blood test. Method Two hundred and fourteen patients were randomized 1:1 to examination with NBI or WLE. The primary outcome measure was the proportion of patients with at least one adenoma detected. Secondary outcomes included total adenomas and polyps, flat adenomas, nonadenomatous polyps, advanced adenomas and patients with three or five or more adenomas. A post hoc analysis to examine the effect of endoscopist and bowel preparation was performed. Results There was no significant difference in the proportion of patients with at least one adenoma: NBI 73% vs WLE 66%, odds ratio 1.40 (95% CI 0.78-2.52), P = 0.26. There was no significant difference for any secondary outcome measure except for the number of flat adenomas which was significantly greater with NBI [comparison ratio 2.66 (95% CI 1.52-4.63), P = 0.001]. Post hoc analysis indicated that one of three endoscopists performed significantly better for adenoma detection with NBI than WLE [comparison ratio 1.92 (95% CI 1.07-3.44), P = 0.03]. Good bowel preparation was associated with significantly improved adenoma detection with NBI [comparison ratio 1.55 (95% CI 1.01-2.22), P = 0.04] but not with fair preparation. Conclusion Overall NBI did not improve detection compared with WLE in a group of patients at high risk for colorectal adenomas, but specific subgroups might benefit. [ABSTRACT FROM AUTHOR]

Abstract: Two patients with rare sites of metastatic pleural mesothelioma are presented and the literature on similar cases is examined. One patient developed colonic metastases from a sarcomatoid mesothelioma. Another patient with epithelioid mesothelioma developed perineal metastases. [Copyright &y& Elsevier]

Endoscopic polypectomy, although routinely used for the treatment of colorectal polyps, may be limited by polyp size, location and histology. Laparoscopic resection for malignant polyps and polyps not amenable to endoscopic removal has the advantage of adequate disease clearance as well as the short-term benefits of laparoscopic surgery. This study evaluates the outcomes of such an approach. Patients who had laparoscopic resection for colorectal polyps between January 2005 and July 2008 were identified from a prospective database. Polyps that were malignant, large, difficult to snare or incompletely excised, were included. Demographics, perioperative details and histopathology were analysed. Seventy-eight patients (44 male) with a median age of 62.5 years (range 24-86) were studied. The majority (79%) were laparoscopic anterior resections for sigmoid or rectal polyps. Median operating time was 125 min (range, 65-225). Eight cases (10.3%) were converted to open mainly due to adhesions. There was no post-operative mortality. Perioperative complications occurred in seven patients (8.9%). Median hospital stay was 6 days (range 4-78). Median polyp size was 20 mm (range, 5-75). There were 44 benign polyps (55.7%); majority were tubulovillous adenomas ( n= 22), and tubular adenomas ( n= 10). Thirty-five patients (44.3%) had invasive cancer, with T1 ( n= 27) and T2 ( n= 2) tumours. Three of these patients (8.6%) had lymph node metastases. Median number of lymph nodes sampled was six (range 0-23). Laparoscopic resection is safe and effective for colorectal polyps not amenable to colonoscopic removal, and is especially important for adequate clearance in the case of malignant polyps. [ABSTRACT FROM AUTHOR]

Background: Colorectal polyps of mesenchymal origin represent a small percentage of gastrointestinal (GI) lesions. Nevertheless, they are encountered with increasing frequency since the widespread adoption of colonoscopy screening. Case presentation: We report a case of a small colonic polyp that presented as intramucosal diffuse spindle cell proliferation with a benign cytological appearance, strong and diffuse immunoreactivity for S-100 protein, and pure Schwann cell phenotype. Careful morphological, immunohistochemical and clinical evaluation emphasize the differences from other stromal colonic lesions and distinguish it from schwannoma, a circumscribed benign nerve sheath tumor that rarely arises in the GI tract. Conclusion: As recently proposed, this lesion was finally described as mucosal Schwann cell hamartoma. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 63-year-old male who was referred for colonoscopy for cancer in diminutive rectal polyp with internal hemorrhoids which was detected by rectal retroflexion. His colonoscopic examination revealed that lesions are above the anorectal junction with atypical features and identified internal hemorrhoids during colonoscopy. Transanal excision was used to remove the cancer with defect closure via a flap without hemorrhage.

Abstract: Background: Colonoscopy is a technically complex procedure commonly performed to detect and remove colorectal pathology. This study examined the influence of provider characteristics on polyp detection, polyp removal, and diagnostic biopsy rates. Methods: We conducted a retrospective cross-sectional study using a 20% sample of 2003 Medicare claims. Primary outcome measures were use of diagnostic biopsy, polyp detection, and polyp removal. We used generalized estimating equations to identify independent predictors of the outcomes, adjusting for patient and provider characteristics. Results: Among 328,167 outpatient colonoscopies, polyp detection and removal rates were significantly lower for nongastroenterologists than gastroenterologists, with adjusted relative risk for polyp detection between 0.80 (95% confidence interval [CI], 0.77-0.83) for general surgeons and 0.93 (95% CI, 0.89-0.98) for internists. Compared with gastroenterologists, diagnostic biopsy was significantly less likely for general (relative risk [RR] 0.69; 95% CI, 0.65-0.74) or colorectal surgeons (RR 0.58; 95% CI, 0.52-0.65). The likelihood of polyp detection and removal was higher for physicians in the middle 2 quartiles of annual colonoscopy volume, but similar for physicians in the highest and lowest volume quartiles. Polyp detection and removal were significantly less likely for examinations in ambulatory surgery centers or offices than hospital outpatient settings, while diagnostic biopsy was significantly less likely in office settings. Conclusions: Physician specialty, annual colonoscopy volume, and site of service are significant predictors of polyp detection, polyp removal, and diagnostic biopsy. These findings may have important implications for the effectiveness of colonoscopy. [Copyright &y& Elsevier]

Rationale and Objectives: Fecal tagging computed tomographic colonography (ftCTC) reduces the discomfort and the inconvenience of patients associated with bowel cleansing procedures before CT scanning. In conventional colonic polyp detection techniques for ftCTC, a digital bowel cleansing (DBC) technique is applied to detect polyps in tagged fecal materials (TFM). However, DBC removes the surface of soft tissues and hampers polyp detection. We developed a colonic polyp detection method for CT colonographic examination that enables the detection of polyps surrounded by air and polyps surrounded by TFM without DBC. Materials and Methods: CT values inside the polyps surrounded by air and polyps surrounded by TFM tend to gradually increase (blob structure) and decrease (inverse-blob structure) from outward to inward, respectively. We developed blob and inverse-blob structure enhancement filters based on the eigenvalues of a Hessian matrix to detect polyps using their intensity characteristic. False-positive elimination is performed using three feature values: volume, maximum value of filter outputs, and standard deviation of CT values inside the polyp candidates. Results: The proposed method is applied to 104 cases of ftCTC images that include 57 polyps larger than 6 mm in diameter. The sensitivity of the method was 91.2% (52/57) with 11.4 false positives per case. Conclusions: The proposed method detects polyps with high sensitivity and 11.4 false positives per case without adverse effects on the DBC. [Copyright &y& Elsevier]

Abstract: Magnification chromoendoscopy, narrow band imaging (NBI) and confocal endomicroscopy can all provide accurate assessment of small and diminutive colonic lesions for neoplastic change that approaches the accuracy of standard histopathology. It is likely that there will be a move to use these techniques in clinical practice for small and particularly diminutive, non-depressed lesions in the near future. Non-neoplastic lesions would be left in situ, and neoplastic lesions resected and disposed of without histopathological assessment. Histopathology would be reserved for larger lesions, indeterminate lesions or lesions where invasion was suspected. There are potentially significant cost savings and patient benefits, with a focussing of histopathological expertise on higher risk lesions, particularly in the era of bowel cancer screening. These techniques may also help target biopsies in colitis surveillance, removing the need for large numbers of random samples. However, in order to convince patients, histopathologists and those funding healthcare of the validity of this approach, further trial data will be needed, with an accreditation process for endoscopists wishing to take on this responsibility. [Copyright &y& Elsevier]

Chromoscopic colonoscopy using indigo carmine is indispensable for the accurate detection of flat neoplastic lesions. In particular, the dye spray technique facilitates the detection of both flat hyperplastic polyps and highly dysplastic lesions. However, magnification chromo-colonoscopy discriminates adenomas from hyperplastic polyps with greater accuracy than conventional methods by showing distinct and visible pit patterns. A pit pattern represents crypt orifices, which reflect the underlying histological structures and colonoscopists can make histological predictions by observing the pit patterns without obtaining biopsy specimens. The pit patterns are classified as types I, II, IIIL, IIIs, IV and V based on histological characterization of normal mucosa, hyperplastic polyp, polypoid adenoma, flat adenoma, tubulo-villous adenoma and cancerous tissue, respectively. In previous reports, overall accuracy ranged from 80 to 95%. In addition, magnification chromo-colonoscopy is useful for the diagnosis of early cancer associated with substantial invasion of the submucosa, in which type V pits are subclassified as types V-I and V-N. The presence of type V-N pits is significant in correlation to cancer with substantial invasion of the submucosa. Magnification chromo-colonoscopy is useful in clinical decision-making when deciding whether endoscopic resection or bowel resection is the appropriate initial procedure to treat lesions. [ABSTRACT FROM AUTHOR]

To assess the ability of transabdominal ultrasound to detect adult colonic polyps and to describe their ultrasonographic appearance. Total colonoscopy was carried out for 729 consecutive patients over a 39-month period. Ultrasonographic examination of the abdomen was followed by specific examination of the colon. Colorectal ultrasound was carried out for patients with colonic polyps of the protruded type (exclusive of advanced cancers and polyps of the flat or depressed types), and cleansing liquid was administered preparatory to colonoscopic examination. In examining colonic polyps we wanted to determine the sensitivity and specificity of ultrasound for detecting colonic polyps, and the presence of power-Doppler flow signals, location, morphologic classification, and size of the polyps. Ultrasound identified no colonic polyps less than 10 mm in diameter in any of the 729 patients. Of the 732 deternimation (three patients had two polyps greater than 10 mm in diameter), ultrasound yielded a positive diagnosis in 16 cases, false-positive in four cases, false-negative in 40 cases, and negative in 672 cases. Sensitivity of the technique was 28.6% and specificity was 99.4% for detection of polyps greater than 10 mm in diameter. Doppler signals were detected in all positive cases. Most polyps that were false-negatives on ultrasound examination occurred in the rectum and sigmoid colon. Sensitivity increased with tumor size, and was as high as 82% (9/11) for polyps exceeding 25 mm in diameter. Fifty-seven percent of pedunculated polyps (type Ip) but no sessile polyps (type Is) were found using ultrasound. Colorectal ultrasound detected adult colonic polyps greater than 10 mm in diameter 16 of the 56 in present 729 patients, suggesting that this method may be of limited value in screening for colonic polyps. [ABSTRACT FROM AUTHOR]

In contrast to common colonic epithelial neoplasms, polypoid mesenchymal tumors of the colon are extremely rare. The majority of uncommon gastrointestinal mesenchymal tumors are associated with the so-called gastrointestinal stromal tumors (GIST). We present a case of a rare colonic pleomorphic sarcoma, macroscopically mimicking a common epithelial colonic polyp, which did not match the criteria of GIST. In this case report we discuss the clinical and pathological characteristics of a rare polypoid-shaped, pleomorphic colonic sarcoma and refer a mark-off to other rare mesenchymal neoplasms of the gut. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) is a noninvasive functional imaging modality that can disclose the presence of a malignant disease. It has recently been reported that PET may be useful to detect primary colorectal cancer (CRC). We present the case of a 47-yr-old man with early colon cancer detected by 18F-fluorodeoxyglucose (FDG) PET. The patient consulted us because of a positive fecal occult blood test and focal FDG uptake in the pelvic cavity detected at a physical check-up. After the usual work up, he was diagnosed as having a sigmoid polyp, 16 mm in diameter. Subsequently, colonoscopic polypectomy was carried out. The surgical specimen was histologically diagnosed as a well-differentiated adenocarcinoma, invading the submucosal layer with lymphatic invasion. Therefore, the involved portion of the sigmoid colon was laparoscopically resected. The FDG PET carried out 1 yr after the operation, showed no abnormal FDG uptake. PET can noninvasively detect an early colon cancer as small as in our patient, as well as other cancers in the whole body. Therefore, we consider it suitable as a screening examination. [ABSTRACT FROM AUTHOR]

Background: Endoscopic removal of large sessile polyps is sometimes technically difficult and is associated with an increased risk of complications. Moreover, the incidence of invasive carcinoma within these polyps is not negligible. Laparoscopic colorectal resection has been recommended in the treatment of these large polyps. This study aimed to evaluate the outcomes of laparoscopic colorectal resection for polyps that were not suitable for colonoscopic removal.Methods: Forty-five patients (28 men and 17 women) who underwent laparoscopic colorectal resection with the preoperative diagnosis of colorectal polyps were analyzed. The reasons for surgical resection were large sessile polyps (n = 34), difficult position (n = 2), recurrence after transanal endoscopic microsurgery (n = 1), and the presence of intramucosal malignancy on histology after colonoscopic polypectomy (n = 8).Results: The mean age of the patients was 66.7 years (range, 33-89). Previous abdominal operation had been performed in 12 patients (26.7%). Two patients underwent subtotal colectomy because of multiple polyps (14 and 19, respectively). Synchronous resection of other organs was performed in two patients (a right salpingo-oophorectomy and a right adrenalectomy). Intraoperative complications occurred in two patients, and two patients (4.5%) required conversion because of perforation of the colon during dissection and dense adhesions, respectively. There was no postoperative mortality. Complications occurred in seven patients (15.6%), and they included postoperative ileus (n = 4), anastomotic leakage (n = 1), urinary retention (n = 1), and urinary tract infection (n = 1). Reoperation was required in one patient for anastomotic leakage. The median hospital stay was 6 days. The histopathology of colorectal polyps showed tubular (n = 12), tubulovillous (n = 13), and villous adenoma (n = 12); mixed adenomatous/hyperolastic polyps (n = 2); inflammatory polyp (n = 1); and colonic lipoma (n = 1). Four patients, who had previous polypectoray with intramucosal malignancy, had no residual pathology. The median size was 3.0 cm. Invasive carcinoma was found in 16 patients (35.6%). The median number of lymph node sampling was six, and two patients had lymph node metastases.Conclusions: Colonic polyps that were not amendable for colonoscopic removal were associated with a high incidence of malignant invasion. Laparoscopic colectomy offers safe and effective management of these polyps with the benefits of early postoperative recovery. [ABSTRACT FROM AUTHOR]

Total excision of colonic polyps is not always attainable and in some patients it is clinically contraindicated. Also, a resected polyp may be lost at any step between its endoscopic removal and its embedding in paraffin. The aim of this study was to compare the histological features of colonic polyps as analysed by the study of biopsy-forceps obtained samples with those assessed on scrutinizing the totally resected growths.This prospective study included a cohort of 59 patients in whom, in the course of an elective colonoscopy, a total excision of a 6 mm-sized or larger polyp was called for. Sizeable biopsies were obtained by means of an Olympus Multibyte forceps prior to the total polypectomy. Subsequent to the study of the polypectomy specimens, the forceps biopsy samples were submitted for histological examination. The pathologists were blinded as to the source of the tissue they were studying. The diagnoses rendered by evaluating the biopsy samples and polypectomy specimens of each patient were contrasted with each other.Major discrepancies between the histological features of the fragments captured by the biopsy-forceps and the factual nature of the totally removed polyps were uncovered in 11 (18.6%) of 59 cases. Intriguingly, the grade of the tumours was underrated in all the 11 cases, as judged by contrasting the tentative diagnoses of the forceps-biopsies with the decisive diagnoses of the polypectomies. Importantly, 2 adenocarcinomas would have been missed by just looking at the forceps-retrieved sample.In our experience, a discordance of 18.6% is to be expected between the diagnoses rendered after examining forceps-biopsies of and totally excised colonic polyps. Nevertheless, it is advisable to procure biopsies prior to the excision of the growths, because on those occasions in which patients' growths cannot be removed or have not been retrieved for one reason or another, a small forceps-captured tissue sample correctly reflects the characteristics of the polyp in 81.4% of the cases. Finally, the biopsies may be discarded in the event that total removal was successful. [ABSTRACT FROM AUTHOR]

PURPOSE: Patients are commonly referred to surgeons for surgical resection of polyps that cannot be excised colono-scopically. Repeating the colonoscopy may be met with resistance by both the patient and the referring endoscopist. However, there are two distinct benefits. First, if the lesion was not marked, tattooing facilitates laparoscopic resection. Second, and more importantly, many of these polyps can be removed endoscopically by an experienced colorectal surgeon, avoiding unnecessary colon resection. Over a period of five years, we have reviewed preoperative colonoscopy in patients who were referred for surgical treatment of benign polyps. METHODS: From January 1999 through September 2003 all patients referred for surgical resection of a benign polyp were consecutively entered into a database by a single group of colorectal surgeons. All patients underwent preoperative colonoscopy on the day before the planned colon resection. Patient charts were reviewed, and demographics were recorded. The referral and preoperative colonoscopy reports and all pathology results were reviewed to record the polyp size, location, histology, and subsequent treatment. RESULTS: Altogether, 71 patients were included in this study. The average size of the polyps was 24 mm (range, 10-60 mm). The location of the polyp as determined by preoperative colonoscopy differed from the location noted on referral colonoscopy in nine patients (13 percent). Surgery was canceled in 23 patients (32 percent), primarily because of complete polypectomy at preoperative colonoscopy. Of the 48 who underwent surgery, 23 (47 percent) had a colonic tattoo placed, at the discretion of the surgeon. Lesions clearly located in the cecum were not tattooed routinely. Of the 48 patients who underwent surgery, 45 (94 percent) underwent laparoscopic colon resection. CONCLUSIONS: We concluded that patients referred for surgical resection of a polyp should undergo repeat colonoscopy preoperatively, given that in our study one-third of patients were spared unnecessary colectomy. In addition, repeat endoscopy by the operating surgeon offers an opportunity to confirm the location of the lesion and place a colonic tattoo to facilitate laparoscopic resection. [ABSTRACT FROM AUTHOR]

In this paper, a method is presented for detection of colonic polyps using both morphological and texture features of the colon wall from the abdominal computed tomography (CT) images. This method consists of two steps. In the first step, suspicious patches of the colon wall are quickly identified by utilizing special local and global geometrical information of the segmented inner-wall mucosa layer. In the second step, a special mapping strategy is employed to identify the growing region of each suspected polyp. Then its internal CT density textures are extracted and quantitatively analyzed based on an assumed ellipsoid polyp model. Finally, both the extracted texture and morphological information are applied to eliminate the false-positives from the identified suspicious patches. With all the extracted geometrical, morphological and texture features, this presented computer-aided detection (CAD) method has demonstrated a significant improvement in detection of the colonic polyps over the previously reported geometry-based CAD methods for CT-based virtual colonoscopy. [Copyright &y& Elsevier]

We developed a novel computer-aided detection (CAD) algorithm called the surface normal overlap method that we applied to colonic polyp detection and lung nodule detection in helical computed tomography (CT) images. We demonstrate some of the theoretical aspects of this algorithm using a statistical shape model. The algorithm was then optimized on simulated CT data and evaluated using a perlesion cross-validation on 8 CT colonography datasets and on S chest CT datasets. It is able to achieve 100% sensitivity for colonic polyps 10 mm and larger at 7.0 false positives (FPs)/dataset and 90% sensitivity for solid lung nodules 6 nun and larger at 5.6 FP/dataset. [ABSTRACT FROM AUTHOR]

Objective: To define the relative risk of malignant transformation in colorectal adenomas less than 10 mm in diameter. Design: Prospective study. Setting: District general hospital, UK. Subjects and materials: 1228 polyps detected endoscopically in 445 patients over the 10-year period 1989-1999. Main outcome measures: Site, size, histological type and dysplastic grade of polyp. Results: 657 of the 1228 polyps were adenomas: 281 (43%) tubular, 339 (51%) tubulovillous and 37 (6%) villous. In the 357 adenomas less than 10 mm in diameter, 11 (3%) were severely dysplastic and 2 carcinomas were detected, though neither was less than 5 mm in size. The relative risk of malignancy or severe dysplasia in adenomas of 10 mm or more compared with those of less than 10 mm was 3.8 (p < 0.0001). Conclusions: Although severe dysplasia and malignancy do occur in adenomas less than 10 mm in size, they are rare in lesions of less than 5 mm. We recommend routine destruction of all polyps 5 mm or more in size, though it is not essential to remove those of less than 5 mm if they are kept under surveillance. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the computed tomography (CT) virtual colographic features of colonic polyps, colorectal cancer, diverticula, ulcerative colitis and other benign colonic lesions. Also, to assess the value of this method in the diagnosis of colorectal lesions. METHODS: Computed tomography colography was performed in 37 patients (26 male, 11 female) suffering from the following conditions: 20 colonic adenomas, six colon cancers, four diverticula, five ulcerative colitis and one each of melanosis coli and amyloidosis. The data from CT scanning were processed by computer with specific software and the colonic lesions were evaluated with 2- or 3-D images, depending on the individual software. RESULTS: Seventeen cases of colonic adenoma, six colon cancers, four diverticula and two cases of ulcerative colitis were detected by using CT colography. However, melanosis coli and amyloidosis of the colon were not detected. CONCLUSION: Computed tomography colography can detect all colonic polyps of 0.5 cm in diameter or larger, colon cancer, diverticula and some ulcerative colitis successfully. It is quick, minimally invasive and able to be tolerated well. It has the potential to become an effective radiological tool in diagnosing colonic lesions. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this feasibility study was to evaluate the diagnostic accuracy of ultra-low-dose CT colonography using iterative reconstruction algorithms with reference to standard colonoscopy., Materials and Methods: Prior to this study, a phantom study was performed to investigate the optimal protocol for ultra-low-dose CT colonography. A total of 206 patients with average/high risk of colorectal cancer were recruited. After undergoing full bowel preparation, the patients were scanned in the prone and supine positions with the CT conditions set to 120 kV, standard deviation 45 to 50, and an adaptive iterative reconstruction algorithm applied. Two expert readers read the images independently. The main outcome measures were the per-patient and per-polyp accuracies for the detection of polyps ≥ 10 mm, with colonoscopy results as the reference standard., Results: Two hundred patients (102 females, mean age 67.5 years) underwent both ultra-low-dose CT colonography and colonoscopy on the same day. The mean radiation exposure dose was 0.64 ± 0.34 mSv. On colonoscopy, 39 patients had 45 polyps ≥ 10 mm (non-polypoid morphology 7), including 4 cancers. Per-patient sensitivity, specificity, and accuracy of CT colonography for polyps ≥ 10 mm were 0.74, 0.96, and 0.92 for reader one, and 0.74, 0.99, and 0.94 for reader two, respectively. Per-polyp sensitivities for polyps ≥ 10 mm were 0.73 for reader one and 0.71 for reader two. On subgroup analysis by morphology, non-polypoid polyps ≥ 10 mm were not detected by both readers., Conclusion: Extreme ultra-low-dose CT colonography had an insufficient diagnostic performance for the detection of polyps ≥ 10 mm, because it was unable to detect non-polypoid polyps. This study showed that the problem with ultra-low-dose CT colonography was the lack of detectability of small-size polyps, especially non-polypoid polyps. To use ultra-low-dose CT colonography clinically, it is necessary to resolve the problems identified by this study., (© 2022. The Author(s) under exclusive licence to Japan Radiological Society.)

Introduction: Schistosomiasis is a trematodes infection more prevalent in tropical and subtropical areas such as Yemen. Giant colonic polyp manifestations of intestinal bilharziasis are uncommon, difficult to differentiate from other colonic polyps, and can mimic cancer., Case Report: A 10-year-old child presented with chronic abdominal pain that started ten months ago. The patient had a family history of lymphoma in his brother. The computed tomography scan showed a sigmoid luminal mass measuring 10×3 cm with significant lumen narrowing and diffuse circumferential wall thickening of the sigmoid colon, hepatomegaly, and multiple perilesional, para-hepatic, and pulmonary lymph nodes enlargements. The mass was morphologically mimicked cancer and proved to be of bilharzial etiology ( Schistosoma mansoni ) after surgical excision., Conclusion: Even though the bilharzial colonic polyps are rare, it is challenging to differentiate them from other malignant colonic polyps. Clinicians should have a high suspicion regarding its manifestations to avoid unnecessary surgical interventions, especially in an endemic area, even in patients with a strong family history of cancer., Competing Interests: The authors declare that they have no conflicts of interest in this work., (© 2022 Alyhari et al.)

Background: Guidelines for surveillance colonoscopy depend on polyp histology. When patients present to a new healthcare system and report a personal history of "colon polyps," however, information on polyp histology is frequently unavailable., Aims: To assess adenoma prevalence in patients with a history of colonic polyps of unknown histology and to compare it to patients undergoing either screening colonoscopy or surveillance colonoscopy for known adenomatous polyps., Methods: This cohort study evaluated colonoscopies of patients ≥ 50 years of age over a 14-year period at a single institution. The exposure of interest was colonoscopy indication, categorized into three groups: screening colonoscopy, surveillance colonoscopy for history of colonic polyp(s) of unknown histology, and surveillance colonoscopy for history of adenoma(s). The primary outcome was adenoma detection rate. Multivariable logistic regression was used to assess the association between colonoscopy indication and adenoma detection rate., Results: Of 31,856 colonoscopies, the adenoma prevalence was 26.1% for patients undergoing screening colonoscopy, 32.9% for patients with a history of polyps of unknown histology, and 41.9% for patients with a history of known adenomatous polyps. Relative to screening colonoscopies, there were higher odds of adenoma detection in surveillance colonoscopies for polyps of unknown histology (aOR compared to screening 1.42, 95% CI 1.30-1.55) and even higher odds among surveillance colonoscopies for a history of adenoma (aOR compared to screening 1.89, 95% CI 1.75-2.05)., Conclusion: The adenoma prevalence on surveillance colonoscopy for patients with polyps of unknown histology was higher than that of screening colonoscopies but lower than that of surveillance colonoscopies for patients with adenomatous polyps., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objectives: To investigate the differentiation of premalignant from benign colorectal polyps detected by CT colonography using deep learning., Methods: In this retrospective analysis of an average risk colorectal cancer screening sample, polyps of all size categories and morphologies were manually segmented on supine and prone CT colonography images and classified as premalignant (adenoma) or benign (hyperplastic polyp or regular mucosa) according to histopathology. Two deep learning models SEG and noSEG were trained on 3D CT colonography image subvolumes to predict polyp class, and model SEG was additionally trained with polyp segmentation masks. Diagnostic performance was validated in an independent external multicentre test sample. Predictions were analysed with the visualisation technique Grad-CAM++., Results: The training set consisted of 107 colorectal polyps in 63 patients (mean age: 63 ± 8 years, 40 men) comprising 169 polyp segmentations. The external test set included 77 polyps in 59 patients comprising 118 polyp segmentations. Model SEG achieved a ROC-AUC of 0.83 and 80% sensitivity at 69% specificity for differentiating premalignant from benign polyps. Model noSEG yielded a ROC-AUC of 0.75, 80% sensitivity at 44% specificity, and an average Grad-CAM++ heatmap score of ≥ 0.25 in 90% of polyp tissue., Conclusions: In this proof-of-concept study, deep learning enabled the differentiation of premalignant from benign colorectal polyps detected with CT colonography and the visualisation of image regions important for predictions. The approach did not require polyp segmentation and thus has the potential to facilitate the identification of high-risk polyps as an automated second reader., Key Points: • Non-invasive deep learning image analysis may differentiate premalignant from benign colorectal polyps found in CT colonography scans. • Deep learning autonomously learned to focus on polyp tissue for predictions without the need for prior polyp segmentation by experts. • Deep learning potentially improves the diagnostic accuracy of CT colonography in colorectal cancer screening by allowing for a more precise selection of patients who would benefit from endoscopic polypectomy, especially for patients with polyps of 6-9 mm size., (© 2022. The Author(s).)

A large bowel obstruction (LBO) is an emergency condition that requires early diagnosis and prompt treatment, and it is also crucial to identify the cause of the obstruction. Here, we describe a 76-year-old woman who presented to the hospital with a 1-day history of abdominal pain and vomiting and was diagnosed with LBO. Endoscopic findings showed that the cause of the LBO was initially determined to be a Bormann Type I tumour in the sigmoid colon. However, the surgery was performed later; the pathological findings led to the diagnosis of colonic obstruction caused by a colonic polyp in the sigmoid colon narrowed by chronic diverticulitis. Colonic polyps rarely cause LBO. Poor observation due to colonic stenosis can mask the morphology of the lesion. In cases of LBO, colonic polyps should be differentially diagnosed in addition to colon cancer., (Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2022.)

Endoscopic mucosal resection (EMR) was originally described in 1973 and is currently a popular practice used in treating polyps, small adenomas, and early cancers. Although the safety of EMR has been proven in numerous studies, complications occur occasionally. We report a case in which the patient complained of severe upper abdominal pain and who was diagnosed with acute appendicitis after colorectal EMR. The patient recovered well after surgery. Cautious observation is necessary when resuming oral intake in patients who undergo colorectal EMR and who complain of postoperative abdominal pain. Observation is especially important for patients with a fecalith that may have originally existed in the appendix or in the colon near the appendix.

Objectives: Post-polypectomy surveillance intervals should be determined based on index colonoscopy findings. However, the risk of metachronous lesions, resulting from the coexistence of adenoma and sessile serrated lesions (SSLs), has rarely been addressed. We evaluated the impact of synchronous SSL on the risk of metachronous lesions within similar adenoma risk groups., Methods: We retrieved individuals with one or more adenomas on index colonoscopy in a single-center retrospective cohort and stratified them into four groups depending on the presence of SSL and low-risk/high-risk adenoma (LRA/HRA). Participants who underwent surveillance colonoscopies at least 12 months apart were included. We compared the risks of metachronous lesions including HRA, advanced adenoma (AA), or SSL within similar adenoma risk groups according to the presence of SSL., Results: Overall 4493 individuals were included in the analysis. The risk of metachronous HRA/AA was not significantly higher in the adenoma with SSL group compared with the adenoma without SSL group, irrespective of LRA (HRA, 6/86 vs. 231/3297, P = 1.00; AA, 0/86 vs. 52/3297, P = 0.64) or HRA (HRA, 11/64 vs. 240/1046, P = 0.36; AA, 3/64 vs. 51/1046, P = 1.00). However, the risk of metachronous SSL in individuals with synchronous SSL was higher than that in those without SSL for both LRA (15/86 vs. 161/3297, P < 0.001) and HRA groups (11/64 vs. 61/1046, P = 0.002)., Conclusion: The presence of synchronous SSL did not increase the risk of metachronous HRA/AA, compared with isolated adenoma, but increased the risk of metachronous SSL., (© 2021 Japan Gastroenterological Endoscopy Society.)

Background: Cold snare polypectomy is being increasingly adopted; however, there are few reports of cold snare polypectomy regarding antithrombotic therapy., Aims: This study aimed to investigate the real-world safety of cold snare polypectomy during antithrombotic therapy., Methods: We collected data from consecutive patients undergoing cold snare polypectomy in a single hospital between 2013 and 2017. Indications for cold snare polypectomy were any ≤ 10 mm polyp. The primary outcome was delayed bleeding. We compared rates of delayed bleeding between patients with and without antithrombotic therapy and analyzed risk factors for delayed bleeding using binary logistic regression model with firth procedure., Results: In 2152 patients (mean age 67.6 years; male 1411), 4433 colorectal polyps (mean diameter 5.0 mm) underwent cold snare polypectomy. Clipping during the procedure was performed for 5.8%. Delayed bleeding occurred in 0.51% (11/2152) of patients and 0.25% (11/4433) of polyps, but no major delayed bleeding occurred. A total of 244 (11%) patients received antithrombotic therapy. Patients on antithrombotic therapy were older (p < 0.001), more likely male (p < 0.001) and had cold snare polypectomy in the proximal colon (p = 0.011). The rate of delayed bleeding was higher in patients on antithrombotic therapy (1.64% vs. non-antithrombotic therapy 0.37%, p = 0.009). Larger polyp size (> 5 mm), use of clips, and antithrombotic therapy were significant risk factors for delayed bleeding. There was no clear association between specific antithrombotic agents and delayed bleeding., Conclusions: Delayed bleeding after cold snare polypectomy was rare even in patients with antithrombotic therapy, and no major delayed bleeding occurred., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)