Fundic gland polyps related to diverse aetiologies show subtle morphological differences: a multicentre retrospective study.

AIMS: Fundic gland polyps (FGPs) comprise 66% of all gastric polyps. Although they are usually non-syndromic, they may be associated with various syndromes, including familial adenomatous polyposis (FAP) or gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). We aimed to evaluate how histological features relate to distinct FGP subtypes. METHODS AND RESULTS: We performed a retrospective analysis of 118 FGPs from 109 patients for the architecture of fundic glands, microcyst lining, parietal cell hyperplasia and surface foveolar epithelial changes. Age, gender and history of FAP or GAPPS were collected. Based on combinations of histological features, three distinct patterns (A, B and C) of FGPs were delineated and correlated to the aetiologies. Non-syndromic FGPs were well-formed polyps composed of disordered fundic glands with intermediate-sized microcysts typically lined by a mixture of oxyntic and mucin-secreting cells (73%). Parietal cell hyperplasia (80%) and foveolar surface hyperplasia (78%) were common. FAP-associated cases demonstrated small microcysts that were predominantly lined by fundic epithelium (77%), with limited parietal cell hyperplasia (27%); foveolar hyperplasia was uncommon. GAPPS-related polyps were the largest, with prominent, mucin-secreting epithelium-lined microcysts (73%). Hyperproliferative aberrant pits were universally present, whereas parietal cell hyperplasia was uncommon. Pattern A was identified in most non-syndromic FGPs (74%) and in a minority of FAP-related FGPs (26%). The majority (82%) of FAP-related FGPs showed pattern B, but only 18% of non-syndromic FGPs did. Pattern C consisted exclusively of GAPPS-associated polyps. CONCLUSIONS: We conclude that, although FGPs share similar histomorphology, subtle differences exist between polyps of different aetiology. In the appropriate clinical setting, the recognition of these variations may help to consider syndromic aetiologies.

Histomorphological analysis of gastric polyps.

INTRODUCTION: Incidence of gastric carcinoma and gastric polyps is on rise all over the world. Chronic atrophic gastritis to intestinal metaplasia progressing to adenocarcinoma has been documented pathway for gastric carcinogenesis. Another pathway for gastric carcinoma is adenoma carcinoma sequence similar to colon cancer. AIM: To study prevalence, endoscopic, and histomorphological features of gastric polyps. METHODS AND MATERIAL: This was retrospective analysis of gastric polyps from 2012 to 2019 in consecutive 10,800 upper gastrointestinal endoscopies. Demographic, endoscopic, and histopathological data were obtained from hospital records. All gastric polyps were classified as per standard histologic criteria. Additional histological features noted were presence of dysplasia, focus of adenoma, or malignancy. RESULTS: The prevalence of gastric polyps was 434 (4%) of 10,800 upper gastrointestinal endoscopies. Majority of polyps were found in the last 4 years (277: 63.8%). Mean age was 55.4 years with male to female ratio 1:1.2. Most of the polyps (94.9%) were less than 1 cm, located in gastric antrum. Multiple polyps were seen in 20.9% cases. On histopathology, fundic gland polyps were most common (147: 33.8%), followed by hyperplastic (128: 29.4%) polyps. Adenomatous polyps were nine (2%); of these, two cases of hyperplastic polyps and one each of fundic gland polyp and benign epithelial polyp showed adenomatous foci. CONCLUSION: Fundic gland polyps were the most common polyps. With rising incidence of gastric carcinoma, identification of gastric polyps on endoscopy with biopsy can prevent progression to carcinogenesis.

External validation of blue light imaging (BLI) criteria for the optical characterization of colorectal polyps by endoscopy experts.

BACKGROUND AND AIM: Recently, the BLI Adenoma Serrated International Classification (BASIC) system was developed by European experts to differentiate colorectal polyps. Our aim was to validate the BASIC classification system among the US-based endoscopy experts. METHODS: Participants utilized a web-based interactive learning system where the group was asked to characterize polyps using the BASIC criteria: polyp surface (presence of mucus, regular/irregular and [pseudo]depressed), pit appearance (featureless, round/non-round with/without dark spots; homogeneous/heterogeneous distribution with/without focal loss), and vessels (present/absent, lacy, peri-cryptal, irregular). The final testing consisted of reviewing BLI images/videos to determine whether the criteria accurately predicted the histology results. Confidence in adenoma identification (rated "1" to "5") and agreement in polyp (adenoma vs non-adenoma) identification and characterization per BASIC criteria were derived. Strength of interobserver agreement with kappa (k) value was reported for adenoma identification. RESULTS: Ten endoscopy experts from the United States identified conventional adenoma (vs non-adenoma) with 94.4% accuracy, 95.0% sensitivity, 93.8% specificity, 93.8% positive predictive value, and 94.9% negative predictive value using BASIC criteria. Overall strength of interobserver agreement was high: kappa 0.89 (0.82-0.96). Agreement for the individual criteria was as follows: surface mucus (93.8%), regularity (65.6%), type of pit (40.6%), pit visibility (66.9%), pit distribution (57%), vessel visibility (73%), and being lacy (46%) and peri-cryptal (61%). The confidence in diagnosis was rated at high ≥4 in 67% of the cases. CONCLUSIONS: A group of US-based endoscopy experts have validated a simple and easily reproducible BLI classification system to characterize colorectal polyps with >90% accuracy and a high level of interobserver agreement.

New polyp image classification technique using transfer learning of network-in-network structure in endoscopic images.

While colorectal cancer is known to occur in the gastrointestinal tract. It is the third most common form of cancer of 27 major types of cancer in South Korea and worldwide. Colorectal polyps are known to increase the potential of developing colorectal cancer. Detected polyps need to be resected to reduce the risk of developing cancer. This research improved the performance of polyp classification through the fine-tuning of Network-in-Network (NIN) after applying a pre-trained model of the ImageNet database. Random shuffling is performed 20 times on 1000 colonoscopy images. Each set of data are divided into 800 images of training data and 200 images of test data. An accuracy evaluation is performed on 200 images of test data in 20 experiments. Three compared methods were constructed from AlexNet by transferring the weights trained by three different state-of-the-art databases. A normal AlexNet based method without transfer learning was also compared. The accuracy of the proposed method was higher in statistical significance than the accuracy of four other state-of-the-art methods, and showed an 18.9% improvement over the normal AlexNet based method. The area under the curve was approximately 0.930 ± 0.020, and the recall rate was 0.929 ± 0.029. An automatic algorithm can assist endoscopists in identifying polyps that are adenomatous by considering a high recall rate and accuracy. This system can enable the timely resection of polyps at an early stage.

An "expressionistic" look at serrated precancerous colorectal lesions.

BACKGROUND: Approximately 60% of colorectal cancer (CRC) precursor lesions are the genuinely-dysplastic conventional adenomas (cADNs). The others include hyperplastic polyps (HPs), sessile serrated lesions (SSL), and traditional serrated adenomas (TSAs), subtypes of a class of lesions collectively referred to as "serrated." Endoscopic and histologic differentiation between cADNs and serrated lesions, and between serrated lesion subtypes can be difficult. METHODS: We used in situ hybridization to verify the expression patterns in CRC precursors of 21 RNA molecules that appear to be promising differentiation markers on the basis of previous RNA sequencing studies. RESULTS: SSLs could be clearly differentiated from cADNs by the expression patterns of 9 of the 12 RNAs tested for this purpose (VSIG1, ANXA10, ACHE, SEMG1, AQP5, LINC00520, ZIC5/2, FOXD1, NKD1). Expression patterns of all 9 in HPs were similar to those in SSLs. Nine putatively HP-specific RNAs were also investigated, but none could be confirmed as such: most (e.g., HOXD13 and HOXB13), proved instead to be markers of the normal mucosa in the distal colon and rectum, where most HPs arise. TSAs displayed mixed staining patterns reflecting the presence of serrated and dysplastic glands in the same lesion. CONCLUSIONS: Using a robust in situ hybridization protocol, we identified promising tissue-staining markers that, if validated in larger series of lesions, could facilitate more precise histologic classification of CRC precursors and, consequently, more tailored clinical follow-up of their carriers. Our findings should also fuel functional studies on the pathogenic significance of specific gene expression alterations in the initiation and evolution of CRC precursor subtypes.

Challenges Facing the Detection of Colonic Polyps: What Can Deep Learning Do?

Colorectal cancer (CRC) is one of the most common causes of cancer mortality in the world. The incidence is related to increases with age and western dietary habits. Early detection through screening by colonoscopy has been proven to effectively reduce disease-related mortality. Currently, it is generally accepted that most colorectal cancers originate from adenomas. This is known as the "adenoma-carcinoma sequence", and several studies have shown that early detection and removal of adenomas can effectively prevent the development of colorectal cancer. The other two pathways for CRC development are the Lynch syndrome pathway and the sessile serrated pathway. The adenoma detection rate is an established indicator of a colonoscopy's quality. A 1% increase in the adenoma detection rate has been associated with a 3% decrease in interval CRC incidence. However, several factors may affect the adenoma detection rate during a colonoscopy, and techniques to address these factors have been thoroughly discussed in the literature. Interestingly, despite the use of these techniques in colonoscopy training programs and the introduction of quality measures in colonoscopy, the adenoma detection rate varies widely. Considering these limitations, initiatives that use deep learning, particularly convolutional neural networks (CNNs), to detect cancerous lesions and colonic polyps have been introduced. The CNN architecture seems to offer several advantages in this field, including polyp classification, detection, and segmentation, polyp tracking, and an increase in the rate of accurate diagnosis. Given the challenges in the detection of colon cancer affecting the ascending (proximal) colon, which is more common in women aged over 65 years old and is responsible for the higher mortality of these patients, one of the questions that remains to be answered is whether CNNs can help to maximize the CRC detection rate in proximal versus distal colon in relation to a gender distribution. This review discusses the current challenges facing CRC screening and training programs, quality measures in colonoscopy, and the role of CNNs in increasing the detection rate of colonic polyps and early cancerous lesions.

Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia.

In addition to the adenoma to carcinoma sequence, colorectal carcinogenesis can occur via the serrated pathway. Studies have focused on clarification of categories and molecular features of serrated polyps, as well as endoscopic detection and risk assessment. Guidelines from the World Health Organization propose assigning serrated polyps to categories of hyperplastic polyps, traditional serrated adenomas, and sessile serrated lesions (SSLs). Traditional serrated adenomas and SSLs are precursors to colorectal cancer. The serrated pathway is characterized by mutations in RAS and RAF, disruptions to the Wnt signaling pathway, and widespread methylation of CpG islands. Epidemiology studies of serrated polyps have been hampered by inconsistencies in terminology and reporting, but the prevalence of serrated class polyps is 20%-40% in average-risk individuals; most serrated polyps detected are hyperplastic. SSLs, the most common premalignant serrated subtype, and are found in up to 15% of average-risk patients by high-detecting endoscopists. Variations in rate of endoscopic detection of serrated polyps indicate the need for careful examination, with adequate bowel preparation and sufficient withdrawal times. Risk factors for SSLs include white race, family history of colorectal cancer, smoking, and alcohol intake. Patients with serrated polyps, particularly SSLs and traditional serrated adenomas, have an increased risk of synchronous and metachronous advanced neoplasia. Surveillance guidelines vary among countries, but SSLs and proximal hyperplastic polyps require special attention in assignment of surveillance interval-especially in light of concerns regarding incomplete detection and resection.

Risk Factors of Multiple Gastric Polyps according to the Histologic Classification: Prospective Observational Cohort Study.

BACKGROUND/AIMS: The aim of this study was to determine the risk factors of multiple gastric polyps according to the histological classification of gastric polyps. METHODS: Subjects with multiple gastric polyps (at least three) during endoscopy were enrolled prospectively. They were assigned to a fundic gland polyp (FGP) group and hyperplastic polyp (HP) group based on a histological classification of gastric polyps. Helicobacter pylori (H. pylori) was confirmed by its histology. Serum gastrin was measured using the radioimmunoassay method. A questionnaire was taken regarding the intake of proton pump inhibitor and nonsteroidal anti-inflammatory drugs, alcohol, smoking history, and diet. RESULTS: Among the 60 subjects enrolled from 2015 to 2018 at Seoul National University Bungdang Hospital, 47 and 13 subjects were assigned to the FGP and HP groups, respectively. The H. pylori infection rate was 12.8% in the FGP group, which is lower than that in the HP group (69.2%, p<0.001). The gastrin level was higher in the HP group (194.7 pg/dL, range 50.6-387.8 pg/dL) than in the FGP group (57.4 pg/dL, range 24.8-79.0 pg/dL) (p=0.007). Histologically, neutrophil infiltration in the antrum and body of the stomach were higher in the HP group than in the FGP group (p=0.022 and p=0.030, respectively). In contrast, monocyte infiltration in the antrum and body of the stomach were higher in the FGP group than in the HP group (p=0.018 and p<0.001, respectively). CONCLUSIONS: HPs arise from inflammation caused by H. pylori. On the other hand, the FGP was not associated with H. pylori or environmental factors.

[Prevalence of histological types of gastric polyps in adult patients from a public hospital in Lima-Peru (2007 - 2016)]. / Prevalencia de tipos histológicos de pólipos gástricos en pacientes adultos de un hospital público de Lima-Perú, en el periodo 2007 al 2016.

OBJECTIVES: Establish the prevalence of gastric polyps detected by upper gastrointestinal endoscopy in patients older than 18 years old during the period from 2007 - 2016 in Cayetano Heredia Hospital. MATERIALS AND METHODS: Retrospective cross-sectional study, performed with data from the gastric biopsies reports of patients that have undergone upper gastrointestinal endoscopy between January 2007 and July 2016. Demographic data, endoscopic characteristics of the polyps and associated histological changes of the surrounding gastric mucosa were evaluated, which were subjected to statistical analysis using STATA v14.2. RESULTS: In a population of 16 552 endoscopies, 407 gastric polyps biopsies were found. These results give a prevalence of 2.5% .Gastric polyps were detected predominantly in women (62.38%). The median age was 61 years (52-71 years). The most frequent histological type was the fundic gland polyp (FGP) (44.85%), followed by the hyperplastic (38.48%) and adenomatous (15.23%) polyp. The most frequent location was in the fundus / corpus (48.65%, p = 0.001). The presence of Hp was detected in 30.6% of the biopsies with polyps. CONCLUSION: The prevalence of gastric polyps is similar to other regions of the world; PGF and hyperplastic are the most frequent. Adenomatous polyps showed a greater relationship with and metaplasia and dysplasia.

Prevalencia de tipos histológicos de pólipos gástricos en pacientes adultos de un hospital público de Lima-Perú, en el periodo 2007 al 2016 / Prevalence of histological types of gastric polyps in adult patients from a public hospital in Lima-Peru (2007 - 2016)

Objetivos: Determinar la prevalencia de pólipos gástricos detectados mediante endoscopía digestiva alta, en pacientes mayores de 18 años del Hospital Cayetano Heredia, en el periodo 2007-2016. Materiales y métodos: Estudio retrospectivo de corte transversal, realizado con datos de biopsias gástricas de pacientes sometidos a endoscopía digestiva alta entre enero de 2007 y julio de 2016. Se evaluó cambios histológicos asociados, datos demográficos y características endoscópicas, las cuales fueron sometidas a análisis estadístico mediante STATA v14.2. Resultados: En una población de 16 552 endoscopías realizadas, se encontró 407 biopsias compatibles con pólipos gástricos, lo cual da una prevalencia de 2,5%. Los pólipos gástricos fueron más frecuentes en mujeres (62,38%). La mediana de edad fue de 61 años (52-71 años). El tipo histológico más frecuente fue el pólipo glandular fúndico (PGF) (44,85%), seguido de pólipo hiperplásico (38,48%) y adenomatoso (15,23%). La localización más frecuente fue en fondo/cuerpo (48,65%, p=0,001) Se detectó la presencia de Helicobacter pylori (Hp) en el 30,6% de las biopsias compatibles con pólipos. Conclusión: La prevalencia de pólipos gástricos es similar con otras regiones del mundo; los PGF e hiperplásicos son los más frecuentes. Los pólipos adenomatosos estuvieron en mayor relación a cambios como metaplasia y displasia.

Objectives: Establish the prevalence of gastric polyps detected by upper gastrointestinal endoscopy in patients older than 18 years old during the period from 2007 - 2016 in Cayetano Heredia Hospital. Materials and methods: Retrospective cross- sectional study, performed with data from the gastric biopsies reports of patients that have undergone upper gastrointestinal endoscopy between January 2007 and July 2016. Demographic data, endoscopic characteristics of the polyps and associated histological changes of the surrounding gastric mucosa were evaluated, which were subjected to statistical analysis using STATA v14.2. Results: In a population of 16 552 endoscopies, 407 gastric polyps biopsies were found. These results give a prevalence of 2.5% .Gastric polyps were detected predominantly in women (62.38%). The median age was 61 years (52-71 years). The most frequent histological type was the fundic gland polyp (FGP) (44.85%), followed by the hyperplastic (38.48%) and adenomatous (15.23%) polyp. The most frequent location was in the fundus / corpus (48.65%, p = 0.001). The presence of Hp was detected in 30.6% of the biopsies with polyps. Conclusion: The prevalence of gastric polyps is similar to other regions of the world; PGF and hyperplastic are the most frequent. Adenomatous polyps showed a greater relationship with and metaplasia and dysplasia.

Accuracy of the Narrow-Band Imaging International Colorectal Endoscopic Classification System in Identification of Deep Invasion in Colorectal Polyps.

BACKGROUND & AIMS: T1 colorectal polyps with at least 1 risk factor for metastasis to lymph node should be treated surgically and are considered endoscopically unresectable. Optical analysis, based on the Narrow-Band Imaging International Colorectal Endoscopic (NICE) classification system, is used to identify neoplasias with invasion of the submucosa that require endoscopic treatment. We assessed the accuracy of the NICE classification, along with other morphologic characteristics, in identifying invasive polyps that are endoscopically unresectable (have at least 1 risk factor for metastasis to lymph node). METHODS: We performed a multicenter, prospective study of data collected by 58 endoscopists, from 1634 consecutive patients (examining 2123 lesions) at 17 university and community hospitals in Spain from July 2014 through June 2016. All consecutive lesions >10 mm assessed with narrow-band imaging were included. The primary end point was the accuracy of the NICE classification for identifying lesions with deep invasion, using findings from histology analysis as the reference standard. Conditional inference trees were fitted for the analysis of diagnostic accuracy. RESULTS: Of the 2123 lesions analyzed, 89 (4.2%) had features of deep invasion and 91 (4.3%) were endoscopically unresectable. The NICE classification system identified lesions with deep invasion with 58.4% sensitivity (95% CI, 47.5-68.8), 96.4% specificity (95% CI, 95.5-97.2), a positive-predictive value of 41.6% (95% CI, 32.9-50.8), and a negative-predictive value of 98.1% (95% CI, 97.5-98.7). A conditional inference tree that included all variables found the NICE classification to most accurately identify lesions with deep invasion (P < .001). However, pedunculated morphology (P < .007), ulceration (P = .026), depressed areas (P < .001), or nodular mixed type (P < .001) affected accuracy of identification. Results were comparable for identifying lesions that were endoscopically unresectable. CONCLUSIONS: In an analysis of 2123 colon lesions >10 mm, we found the NICE classification and morphologic features identify those with deep lesions with >96% specificity-even in non-expert hands and without magnification. ClinicalTrials.gov number NCT02328066.

Subtypes of the Type II Pit Pattern Reflect Distinct Molecular Subclasses in the Serrated Neoplastic Pathway.

BACKGROUND: Colorectal serrated lesions (SLs) are important premalignant lesions whose clinical and biological features are not fully understood. AIMS: We aimed to establish accurate colonoscopic diagnosis and treatment of SLs through evaluation of associations among the morphological, pathological, and molecular characteristics of SLs. METHODS: A total of 388 premalignant and 18 malignant colorectal lesions were studied. Using magnifying colonoscopy, microsurface structures were assessed based on Kudo's pit pattern classification system, and the Type II pit pattern was subcategorized into classical Type II, Type II-Open (Type II-O) and Type II-Long (Type II-L). BRAF/KRAS mutations and DNA methylation of CpG island methylator phenotype (CIMP) markers (MINT1, - 2, - 12, - 31, p16, and MLH1) were analyzed through pyrosequencing. RESULTS: Type II-O was tightly associated with sessile serrated adenoma/polyps (SSA/Ps) with BRAF mutation and CIMP-high. Most lesions with simple Type II or Type II-L were hyperplastic polyps, while mixtures of Type II or Type II-L plus more advanced pit patterns (III/IV) were characteristic of traditional serrated adenomas (TSAs). Type II-positive TSAs frequently exhibited BRAF mutation and CIMP-low, while Type II-L-positive TSAs were tightly associated with KRAS mutation and CIMP-low. Analysis of lesions containing both premalignant and cancerous components suggested Type II-L-positive TSAs may develop into KRAS-mutated/CIMP-low/microsatellite stable cancers, while Type II-O-positive SSA/Ps develop into BRAF-mutated/CIMP-high/microsatellite unstable cancers. CONCLUSIONS: These results suggest that Type II subtypes reflect distinct molecular subclasses in the serrated neoplasia pathway and that they could be useful hallmarks for identifying SLs at high risk of developing into CRC.

Factors Associated With Classification of Hyperplastic Polyps as Sessile Serrated Adenomas/Polyps on Morphologic Review.

BACKGROUND: Distinguishing sessile serrated adenomas/polyp (SSA/P), a subset of serrated polyps, from hyperplastic polyps (HPs) remains a challenge and has surveillance implications. Our goal was to identify clinical and pathologic factors associated with serrated polyps originally read as HPs being reassessed as SSA/Ps versus confirmed as HPs. METHODS: Data were collected from consecutive patients with a right-sided HP and a corresponding comparison group with conventional adenomas between 1993 and 2003. Two experienced gastrointestinal pathologists, blinded to polyp and clinical factors, reinterpreted the HPs using current SSA/P classification criteria. These HPs were classified as SSA/P when diagnostic histologic feature(s) were present in at least 3 crypts. Analyses, conducted on a per polyp basis, examined the factors associated with risk of individual HPs being reassessed as SSA/Ps as opposed to being confirmed as HPs. RESULTS: Of the 702 HPs (355 adults), 188 (26.8%) were reclassified as SSA/Ps. Predictors of HPs being reinterpreted as SSA/Ps included: size ≥5 mm [odds ratio (OR), 2.09; 95% confidence interval (CI), 1.34-3.26], proximal location (OR, 2.83; 95% CI, 1.69-4.74), synchronous adenomas with advanced pathology (OR, 2.61; 95% CI, 1.22-5.55) and ≥1 synchronous HPs (other than HP being reassessed) reclassified as SSA/Ps (OR, 11.76; 95% CI, 6.75-20.49). CONCLUSIONS: Because HP versus SSP is not very reproducible the predictors of SSA/P that we identified, including size, location, and synchronous lesions, can offer some additional help to endoscopists when determining surveillance intervals in patients with serrated polyps. In addition, observed association between SSA/P with advanced conventional neoplasia (but not low-grade adenomas) suggests 2 distinct groups of patient predisposition, one with both advanced conventional and important serrated precursors (SSA/P) and the other largely restricted to nonadvanced conventional adenomas and HPs only. Whether the association reported here has to do with SSA/P diagnosis per se or generally larger size of SSA/P remains to be determined in future studies.

A hierarchical classifier based on human blood plasma fluorescence for non-invasive colorectal cancer screening.

Colorectal cancer (CRC) a leading cause of death by cancer, and screening programs for its early identification are at the heart of the increasing survival rates. To motivate population participation, non-invasive, accurate, scalable and cost-effective diagnosis methods are required. Blood fluorescence spectroscopy provides rich information that can be used for cancer identification. The main challenges in analyzing blood fluorescence data for CRC classification are related to its high dimensionality and inherent variability, especially when analyzing a small number of samples. In this paper, we present a hierarchical classification method based on plasma fluorescence to identify not only CRC, but also adenomas and other non-malignant colorectal findings that may require further medical investigation. A feature selection algorithm is proposed to deal with the high dimensionality and select discriminant fluorescence wavelengths. These are used to train a binary support vector machine (SVM) in the first level to identify the CRC samples. The remaining samples are then presented to a one-class SVM trained on healthy subjects to detect deviant samples, and thus non-malignant findings. This hierarchical design, together with the one class-SVM, aims to reduce the effects of small samples and high variability. Using a dataset analyzed in previous studies comprised of 12,341 wavelengths, we achieved much superior results. Sensitivity and specificity are 0.87 and 0.95 for CRC detection, and 0.60 and 0.79 for non-malignant findings, respectively. Compared to related work, the proposed method presented a better accuracy, required fewer features, and provides a unified approach that expands CRC detection to non-malignant findings.

Diagnostic performance of Japan NBI Expert Team classification for differentiation among noninvasive, superficially invasive, and deeply invasive colorectal neoplasia.

BACKGROUNDS AND AIMS: The Japan NBI Expert Team (JNET) classification is the first universal narrow-band imaging magnifying endoscopic classification of colorectal tumors. Considering each type in this classification, the diagnostic ability of Type 2B is the weakest. Generally, clinical behavior is believed to be different in each gross type of colorectal tumor. We evaluated the differences in the diagnostic performance of JNET classification for each gross type (polypoid and superficial) and examined whether the diagnostic performance of Type 2B could be improved by subtyping. METHODS: We analyzed 2933 consecutive cases of colorectal lesions, including 136 hyperplastic polyps/sessile serrated polyps, 1926 low-grade dysplasias (LGDs), 571 high-grade dysplasias (HGDs), and 300 submucosal (SM) carcinomas. We classified lesions as polypoid and superficial type and compared the diagnostic performance of the classification system in each type. Additionally, we subtyped Type 2B into 2B-low and 2B-high based on the level of irregularity in surface and vessel patterns, and we evaluated the relationship between the subtypes and histology, as analyzed separately for polypoid and superficial types. We also estimated interobserver and intraobserver variability. RESULTS: The diagnostic performance of JNET classification did not differ significantly between polypoid and superficial lesions. Ninety-nine percent of Type 2B-low lesions were LGDs, HGDs, or superficial submucosal invasive (SM-s) carcinomas. In contrast, 60% of Type 2B-high lesions were deep submucosal invasive (SM-d) carcinomas. The results were not different between each gross type. Interobserver and intraobserver agreements for Type 2B subtyping were good, with kappa values of .743 and .786, respectively. CONCLUSIONS: Type 2B subtyping may be useful for identifying lesions that are appropriate for endoscopic resection. JNET classification and Type 2B sub classification are useful criteria, regardless of gross type.

Traditional serrated adenoma (TSA): morphological questions, queries and quandaries.

AIM: Traditional serrated adenoma (TSA) is an uncommon type of serrated adenoma that can be a precursor to biologically aggressive colorectal cancer that invokes the serrated (accelerated) pathway. The purpose of this review is to address some of the more contentious issues around nomenclature, diagnostic criteria, histological variants, coexistence with other polyp types, the occurrence of dysplasia and the differential diagnosis. RESULTS: While the vast majority of TSAs are exophytic villiform polyps composed of deeply eosinophilic cells, flat top luminal serrations and numerous ectopic crypt foci, histological variants include flat TSA, filiform TSA and one composed of large numbers of mucin-containing cells. It is unlikely that there is any biological difference between the histological variants. There is a contention that TSAs are not dysplastic ab initio and that the majority do not show cytological atypia. Two types of dysplasia are associated with TSA. Serrated dysplasia is less well recognised and less commonly encountered than adenomatous dysplasia. TSA with dysplasia must be separated from TSA with coexisting conventional adenoma. CONCLUSIONS: TSA is a characteristic polyp that may be extremely exophytic, flat or composed of mucin-rich cells and is typified by numerous ectopic crypt foci. They may coexist with other serrated polyps and conventional adenomas. Approximately 20-25% will be accompanied by adenomatous dysplasia.

UK guidance for the pathological reporting of serrated lesions of the colorectum.

Bowel cancer screening programmes have highlighted to endoscopists and clinicians the spectrum of serrated colorectal lesions. One of the most significant developments has been the recognition that sessile serrated lesions (SSLs), while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the enhanced development of epithelial dysplasia and colorectal adenocarcinoma. Different minimum criteria exist for the diagnosis of SSLs and their differentiation from HPs. Furthermore, the spectrum of terminology used to describe the entire range of serrated lesions is wide. This variability has impaired interobserver agreement during their histopathological assessment. Here, we provide guidance for the histopathological reporting of serrated lesions, including a simplified nomenclature system. Essentially, we recommend use of the following terms: HP, SSL, SSL with dysplasia, traditional serrated adenoma (TSA) and mixed polyp. It is hoped that this standardisation of nomenclature will facilitate studies of the biological significance of serrated lesions in terms of the relative risk of disease progression.

Traditional serrated adenoma: an update.

Although recognized 25 years ago, the traditional serrated adenoma (TSA) remains an ongoing source of diagnostic and biologic debate. Recent research has greatly improved our understanding of the morphological and molecular aspects of these polyps. In particular, the recognition of ectopic crypt foci (ECFs) in combination with typical cytology and slitlike serrations improves diagnostic reproducibility. Awareness that many TSAs, particularly BRAF-mutated TSAs, arise in precursor microvesicular hyperplastic polyps and sessile serrated adenomas can aid in making this diagnosis and should not be confused with a sessile serrated adenoma with dysplasia. At a molecular level, TSAs can be divided into 2 groups based on their BRAF or KRAS mutation status. The development of overt cytologic dysplasia is accompanied by TP53 mutation, Wnt pathway activation, and, in some cases, silencing of CDKN2A. Importantly, however, mismatch repair enzyme function is retained. Thus, the TSA is an important precursor of aggressive molecular subtypes of colorectal carcinoma.

High resolution microendoscopy for classification of colorectal polyps.

BACKGROUND AND STUDY AIMS: It can be difficult to distinguish adenomas from benign polyps during routine colonoscopy. High resolution microendoscopy (HRME) is a novel method for imaging colorectal mucosa with subcellular detail. HRME criteria for the classification of colorectal neoplasia have not been previously described. Study goals were to develop criteria to characterize HRME images of colorectal mucosa (normal, hyperplastic polyps, adenomas, cancer) and to determine the accuracy and interobserver variability for the discrimination of neoplastic from non-neoplastic polyps when these criteria were applied by novice and expert microendoscopists. METHODS: Two expert pathologists created consensus HRME image criteria using images from 68 patients with polyps who had undergone colonoscopy plus HRME. Using these criteria, HRME expert and novice microendoscopists were shown a set of training images and then tested to determine accuracy and interobserver variability. RESULTS: Expert microendoscopists identified neoplasia with sensitivity, specificity, and accuracy of 67 % (95 % confidence interval [CI] 58 % - 75 %), 97 % (94 % - 100 %), and 87 %, respectively. Nonexperts achieved sensitivity, specificity, and accuracy of 73 % (66 % - 80 %), 91 % (80 % - 100 %), and 85 %, respectively. Overall, neoplasia were identified with sensitivity 70 % (65 % - 76 %), specificity 94 % (87 % - 100 %), and accuracy 85 %. Kappa values were: experts 0.86; nonexperts 0.72; and overall 0.78. CONCLUSIONS: Using the new criteria, observers achieved high specificity and substantial interobserver agreement for distinguishing benign polyps from neoplasia. Increased expertise in HRME imaging improves accuracy. This low-cost microendoscopic platform may be an alternative to confocal microendoscopy in lower-resource or community-based settings.