Advantage of magnifying narrow-band imaging for the diagnosis of colorectal neoplasia associated with sessile serrated lesions

Objectives

This study aimed to extract endoscopic findings for diagnosing colorectal neoplasia associated with sessile serrated lesions (SSLs), which are of significant interest.

Methods

To compare the magnifying narrow-band imaging (NBI) findings with microscopic morphology, we classified SSLs into two groups: Group A SSLs included the majority of uniform SSLs and any dysplasia other than that classified as group B SSLs. Group B SSLs included SSLs with intramucosal and invasive carcinoma. We also quantitatively assessed visible vessels using ImageJ software.

Results

This study included 47 patients with 50 group B SSLs who underwent endoscopic resection between 2012 and 2020. The results were retrospectively compared with those of 237 patients with 311 group A SSLs that underwent endoscopic resection. Using conventional white-light endoscopy, significantly more group B SSLs had uneven shapes and some reddening compared to group A SSLs. The diagnostic odds ratios for group B SSLs were as follows: lesions with a diameter ≥10 mm, 9.76; uneven shape, 3.79; reddening, 15.46; and visible vessels with NBI, 11.32. Regarding visible vessels with NBI, the specificity and diagnostic accuracy for group B SSLs were 94.9% and 93.1%, respectively. The percentage of the vascular tonal area of NBI images was significantly larger for group B SSLs than for group A SSLs (3.97% vs. 0.29%; p < 0.01).

Conclusions

SSLs with reddening and/or a diameter ≥10 mm are suspected to contain cancerous components. Moreover, visible vessels observed using magnifying NBI can serve as objective indicators for diagnosing SSLs with cancerous components with a high degree of accuracy.

Transcriptome of sessile serrated adenoma/polyps is associated with MSI-high colorectal cancer and decreased expression of CDX2

The objective of this study was to elucidate the molecular background of sessile serrated adenoma/polyp (SSA/P) endoscopically resected with comprehensive gene expression analysis. Gene expression profiling was performed for 10 tumor-normal pairs of SSA/P. Cluster analysis, gene set enrichment analysis (GSEA), and consensus molecular subtype (CMS) classification of colorectal cancer (CRC) were applied to our transcriptome analysis. Unsupervised cluster analysis showed that the gene expression profile of SSA/Ps is different from that of adjacent normal epithelial cells, even in the very early stage of tumorigenesis. According to the CMS classification, our microarray data indicated that SSA/Ps were classified as CMS1. GSEA demonstrated a strong association between SSA/P and microsatellite instability-high (MSI-H) CRC (p < 10^-5 ). Transcriptome analysis of five MSI-related genes (MSH2, MSH6, MLH1, PMS1, and PMS2) and five CRC-related genes (BRAF, KRAS, APC, TP53, and CDX2) showed that CDX2 expression was most severely decreased in SSA/P. Immunohistochemical staining confirmed that CDX2 protein was reduced compared with the surrounding mucosa. Direct sequencing of the BRAF gene showed that the BRAF V600E mutation was detected in only nine of 36 cases. In a mouse model, BRAF, APC, or CDX2 deficiency indicated that the gene expression pattern with loss of CDX2 is more similar to our SSA/Ps compared with those induced by BRAF or APC mutation. Transcriptome analysis of SSA/Ps showed characteristic gene expression with a strong resemblance to MSI-H CRC. Downregulation of CDX2 expression is an essential molecular mechanism involved in the initial stage of SSA/P tumorigenesis. (UMIN000027365).

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Sessile serrated adenoma/polyp showed rapid malignant transformation in the final 13 months

Based on the concept of the adenoma-carcinoma sequence, most colorectal cancers are considered to arise from conventional adenomas. However, recent studies suggested that a subset of colorectal cancers develop through the serrated neoplastic pathway. It has also been documented that serrated polyps can rapidly transform into invasive cancers even when they are small in size. We now describe a case of a sessile serrated adenoma/polyp which had been followed up for 4 years but eventually showed rapid transformation into an advanced cancer accompanied by a remarkable morphological change within only 13 months. Retrospective genetic and epigenetic analyses showed microsatellite instability, CpG island methylator phenotype-positive, and BRAF mutation in the lesion, suggesting the tumor had developed through the serrated neoplastic pathway. This case may provide valuable information about the natural history of sessile serrated adenoma/polyps which eventually progress to advanced cancers.

Associations between gastric histopathology and the occurrence of colonic polyps

AIM

Compromise of the gastric acid barrier may facilitate bacterial invasion of the lower intestinal tract and promote the development of colonic neoplasia. Our study aimed to test the associations between histopathological abnormalities of the upper and lower gastrointestinal tract in patients undergoing bidirectional endoscopy.

METHOD

The Inform Diagnostics database is a national electronic repository of histopathological records of patients distributed throughout the USA. A case-control study of 302 061 patients, 163 168 of whom had colonic polyps, evaluated whether the occurrence of colonic polyps was influenced by the presence of the following gastro-oesophageal diagnoses: gastric Helicobacter pylori infection, gastric intestinal metaplasia, fundic gland polyps and gastric hyperplastic polyps. The influence of individual diagnoses on the occurrence of colonic polyps was expressed as odds ratios with their 95% confidence intervals.

RESULTS

The odds ratio for tubular adenomas being associated with gastric H. pylori was 1.53 (1.49-1.58), with intestinal metaplasia 1.65 (1.59-1.71), with fundic gland polyps 1.49 (1.45-1.54) and with gastric hyperplastic polyps 1.85 (1.75-1.96). The odds ratio for sessile serrated polyps being associated with gastric H. pylori was 1.03 (0.96-1.10), with intestinal metaplasia 1.21 (1.13-1.30), with fundic gland polyps 1.79 (1.69-1.89) and with gastric hyperplastic polyps 1.52 (1.35-1.71.

CONCLUSION

A diminished gastric acid barrier function, which occurs in various upper gastrointestinal diseases associated with lowered gastric acid output, may promote the development of colonic neoplasia.

Folic acid supplementation and risk of colorectal neoplasia during long-term follow-up of a randomized clinical trial

BACKGROUND

The Aspirin/Folate Polyp Prevention Study previously found folic acid increased risk of advanced and multiple colorectal adenomas during a surveillance colonoscopy interval starting about 3 y after randomization.

OBJECTIVE

We conducted secondary analyses to evaluate folic acid effects with additional follow-up after treatment was stopped.

METHODS

In total, 1021 participants recently diagnosed with colorectal adenomas were randomly assigned to 1 mg/d of folic acid (n = 516) or placebo (n = 505), with or without aspirin, beginning 6 July 1994. The original 3-y treatment period was extended into a subsequent colonoscopy interval, but eventually stopped prematurely on 1 October 2004. With additional post-treatment follow-up, a total of 663 participants who extended treatment completed a second colonoscopic surveillance interval after the initial 3-y follow-up. In addition, 490 participants provided information regarding a subsequent surveillance colonoscopy occurring before completion of follow-up on 31 May 2012, including 325 who had agreed to extended treatment. Study endpoints included conventional adenomas, sessile serrated adenomas/polyps (SSA/Ps), or colorectal cancer, and RRs with 95% CIs were adjusted for baseline characteristics associated with availability of follow-up.

RESULTS

Among those who extended treatment, any colorectal neoplasia was found in 118 (36%) participants assigned to placebo and 146 (43%) assigned to folic acid during the second surveillance interval (RR: 1.21; 95% CI: 0.99, 1.47; P = 0.06). Increased risk of SSA/P with extended folic acid supplementation was statistically significant during the second surveillance interval (RR: 1.94; 95% CI: 1.02, 3.68; P = 0.04). There was no evidence of post-treatment effects for any colorectal neoplasia (RR: 1.01; 95% CI: 0.80, 1.28; P = 0.94), and the post-treatment effect for SSA/P was no longer statistically significant (RR: 1.38; 95% CI: 0.59, 3.19; P = 0.46).

CONCLUSIONS

Delayed treatment effects were not observed, but folic acid may increase SSA/P risk. This trial was registered at clinicaltrials.gov as NCT00272324.

Loss of expression of MLH1 in non-dysplastic crypts is a harbinger of neoplastic progression in sessile serrated adenomas/polyps

AIMS

Dysplasia in colonic sessile serrated adenomas (SSAs)/sessile serrated polyps often shows loss of MLH1 expression as determined with immunohistochemistry, but the significance of loss of MLH1 expression in non-dysplastic crypts in these polyps is less well studied. The purpose of this study was to evaluate the prevalence of loss of MLH1 expression in non-dysplastic crypts in SSAs, and to evaluate its significance with regard to progression of these polyps.

METHODS AND RESULTS

Four hundred SSAs, including 158 SSAs without dysplasia, 219 SSAs with dysplasia (SSAD), and 23 SSAs with invasive adenocarcinoma (SSAC), were evaluated immunohistochemically for loss of MLH1 expression in both non-dysplastic and dysplastic portions of the polyps. Seventy-one of 400 (18%) SSAs showed loss of MLH1 expression in non-dysplastic crypts. The prevalence of MLH1-deficient non-dysplastic crypts was higher in polyps with dysplasia or carcinoma (7%, 22%, and 52% in SSAs, SSADs, and SSACs, respectively; P < 0.0001). When SSAs with MLH1-deficient dysplasia and those with MLH-1-proficient dysplasia were compared, those with MLH1-deficient dysplasia were more likely to have MLH1-deficient non-dysplastic crypts (66% versus 8.1%, P < 0.0001) and a greater number of discrete foci (3.6 foci versus 1.1 foci, P = 0.008). Also, non-dysplastic crypts with loss of MLH1 expression were more likely to be contiguous with the dysplasia when the dysplasia also showed loss of MLH1 expression (26% versus 0%, P = 0.02).

CONCLUSIONS

Our results suggest that loss of MLH1 expression in non-dysplastic crypts in SSAs precedes the development of MLH1-deficient dysplasia and adenocarcinoma, and may be a biomarker of an advanced serrated polyp even in the absence of dysplasia.

Clinical and endoscopic evaluations of sessile serrated adenoma/polyps with cytological dysplasia

BACKGROUND AND AIM

Although sessile serrated adenoma/polyps (SSA/Ps) are considered to be premalignant lesions and rapidly progress to carcinomas after they develop cytological dysplasia (CD), a treatment strategy for SSA/Ps in Asian countries is still being debated and has not yet been established. The present study aimed to propose a treatment strategy for SSA/Ps.

METHODS

Histopathological data of patients, who underwent colonoscopy at our center between January 2011 and December 2016, were reviewed. Data of patients with ≥ 1 SSA/P were retrieved, and clinicopathological characteristics were retrospectively analyzed.

RESULTS

A total of 281 patients with 326 SSA/Ps, including 258 patients who had 300 SSA/Ps without CD (SSA/Ps-CD[-]) and 23 patients who had 26 SSA/Ps with CD (SSA/Ps-CD[+]), were evaluated in this study. Although SSA/Ps-CD(+) were often found in older female patients and in the proximal colon, there were no significant differences between SSA/Ps-CD(-) and SSA/Ps-CD(+). Endoscopic morphological findings, such as large or small nodules on the surface and partial protrusion of the lesions, were significantly more common in SSA/Ps-CD(+) than in SSA/Ps-CD(-). Although the diagnostic ability of nodule/protrusion in lesions to predict CD within SSA/Ps was very high with an accuracy of 93.9% and a negative predictive value of 95.4%, sensitivity was low at 46.2%. SSA/Ps-CD(+) were significantly larger than SSA/Ps-CD(-), and the rate of CD within SSA/Ps significantly increased with lesion size (≤ 5 mm, 0%; 6-9 mm, 6.0%; ≥ 10 mm, 13.6%).

CONCLUSION

The study proposes removing all SSA/Ps ≥ 6 mm in order to remove high-risk SSA/Ps-CD(+), with high sensitivity.

Adjunctive use of chromoendoscopy may improve the diagnostic performance of narrow-band imaging for small sessile serrated adenoma/polyp

BACKGROUND AND AIM

Endoscopic diagnosis of sessile serrated adenoma/polyp (SSA/P) is challenging because of their subtle appearance. Narrow-band imaging (NBI) is useful for diagnosis, but its utility with concurrent chromoendoscopy (CE), especially to detect small SSA/P, is unproven.

METHODS

This prospective study enrolled 367 consecutive patients who underwent screening colonoscopy with the finding of serrated polyps. Patients were divided into derivation and validation cohorts: Diagnostic criteria using different endoscopic modalities were generated by regression analysis in the derivation cohort and were validated in the validation cohort for sensitivity, specificity, and accuracy.

RESULTS

There were 180 patients with 119 SSA/P and 147 hyperplastic polyps (HP) in the derivation cohort and 187 patients with 177 SSA/P and 125 HP in the validation cohort. With white-light endoscopy plus NBI, mucus cap, surface grooves, and expanded crypt were most associated with SSA/P. With white-light endoscopy plus CE, II-O pit pattern, mucus cap, and superficial telangiectasia were most associated with SSA/P. With the combined use of these three modalities, II-O pit pattern, mucus cap, and surface grooves were most associated with SSA/P. For large serrated polyp, NBI in combination with CE had a better accuracy than NBI alone (91% vs 86%, P = 0.025) to distinguish SSA/P from HP. CE alone had a better accuracy than NBI alone for distinguishing small SSA/P from small HP (85% vs 72%, P < 0.0001).

CONCLUSION

Compared with NBI alone, adjunctive use of CE can improve the diagnostic accuracy for distinguishing SSA/P from HP, especially for small SSA/P.

Protein expression of Fragile Histidine Triad and cyclooxgenase-2 in serrated neoplasia of the colorectum

The adenoma-carcinoma sequence (ACS) and the serrated pathway are two distinct developmental routes leading to the formation of colorectal carcinoma (CRC). However, the mechanism triggered by the serrated pathway remains unclear. Therefore, to clarify the molecular and clinicopathological characteristics of the serrated tumorigenic pathway, immunohistochemistry was used to examine the expression of Fragile Histidine Triad (FHIT), cyclooxygenase-2 (COX-2), MutL homolog 1 (MLH1), MutS protein homolog 2 (MSH2) and P53 in endoscopically resected samples of 62 serrated polyps. These samples included 20 hyperplastic polyps (HPs), 16 traditional serrated adenomas (TSAs), 26 sessile serrated adenoma/polyps (SSA/Ps), 20 non-serrated adenomas, 20 carcinoma in adenomas (CIAs) and 18 early pure CRCs without any adenoma component (EPCs). FHIT expression was markedly reduced or absent in 50% of TSA samples, 92.3% of SSA/Ps and 44% of EPCs, but only rarely in HPs, non-serrated adenomas and CIAs. COX-2 expression was more common in non-serrated adenomas compared with in serrated polyps, and was present in 25 and 3.2% of the cases respectively (P<0.01). Furthermore, COX-2 expression was more frequent in CIAs (60%) compared with in EPCs (22.2%; P<0.05). The incidence of negative COX-2 expression was higher in FHIT-negative SSA/Ps compared with in FHIT-positive SSA/Ps (P=0.08). A total of 16.7% of EPC samples and 11.5% of SSA/Ps demonstrated a loss of MLH1/MSH2 expression, but none of the other tumor types did. P53 overexpression was significantly increased in EPC (77.8%) and CIA (60%) samples compared with in HP (0%), TSA (6.6%), SSA/P (0%) and non-serrated adenoma (10%) samples (P<0.01). These findings demonstrated that there are different expression patterns between the serrated pathway and ACS, indicating that aberrant FHIT and inhibited COX-2 expression may be associated with serrated tumorigenesis. In addition, this data indicated that EPC may contain tumors derived from the serrated pathway as well as ACS.

Colorectal cancer anatomic distribution patterns remain the same after sessile serrated adenoma/polyp considered cancer precursor: a 9-year comparison study from community-based endoscopy centers

BACKGROUND

The overall incidence of colorectal cancer (CRC) in the United States has steadily decreased. However, the incidence of right-sided CRC remains unchanged for the past two decades. The serrated neoplastic pathway (sessile serrated adenoma/polyp, SSA/P) has been considered an important pathway of colorectal carcinogenesis, especially in the right-sided CRC. The aim of this study was to compare CRC anatomic distribution patterns in a 9-year interval in the general population before and after SSA/P was recognized and treated as a CRC precursor.

METHODS

The Miraca Life Sciences (MLS) pathology database was queried for all primary CRCs diagnosed between 8/3/2000 to 12/31/2005 (control group) and 1/1/2014 to 12/31/2014 (current group). Patients' demographics, clinical information, and pathology reports were collected and analyzed.

RESULTS

A total of 5,602 patients with 5,685 CRCs were identified, of which 2,728 patients with 2,765 CRCs in current group and 2,874 patients with 2,920 CRCs in control group. Overall, there were no statistical differences in the current group in regards to the anatomical distribution patterns of CRCs in the proximal, right-sided, distal, and left-sided colon or genders compared with the control group (all P>0.05). Among the current group, there were 33 (1.2%) patients with 38 (1.4%) CRCs arising in SSA/Ps [serrated carcinomas (SCAs)], of which 33 (86.8%) were in the right-sided colon and 5 (13.2%) in the left-sided colon. Twenty-three (69.7%) SCA patients were female with significant advanced age than male (76.4 vs. 69.6, P=0.023).

CONCLUSIONS

The overall current CRC anatomic distribution patterns after SSA/Ps managed as CRC precursor remain the same in the patients' population from the community-based endoscopy centers in the U.S. It is suggested that the current SSA/P management might need to be further modified.

Serrated Polyps and Serrated Polyposis Syndrome

Colorectal serrated polyps are intermediate lesions in the serrated neoplastic pathway, which account for up to 30% of colorectal cancers. This pathway is biologically distinct from the adenoma-to-carcinoma sequence, with associated cancers exhibiting mutations in the BRAF oncogene, DNA promoter hypermethylation, and microsatellite instability. An evolving understanding of these unique lesions has led to the development of a more accurate classification, improved endoscopic identification, and tailored clinical management guidelines. This article reviews serrated polyps and serrated polyposis syndrome.

Colonoscopic features and malignant potential of sessile serrated adenomas: comparison with other serrated lesions and conventional adenomas

AIM

Sessile serrated adenomas/polyps (SSA/Ps) have been proposed as precursors of colorectal cancer. The aims of this investigation were to compare the endoscopic findings of SSA/Ps with those of other serrated lesions and to compare the histological findings of SSA/Ps with those of conventional adenomas.

METHOD

We retrospectively reviewed colonoscopy records at our institution from 1984 to 2013 and identified cases of endoscopically or surgically resected conventional adenomas and serrated lesions, including SSA/Ps, hyperplastic polyps (HPs) and traditional serrated adenomas (TSAs). The colonoscopic findings of SSA/Ps were compared with those of the other two serrated lesions and histological findings were compared among all groups of lesions.

RESULTS

There were 79 HPs in 68 patients, 77 SSA/Ps in 63 patients, 167 TSAs in 145 patients and 6324 conventional adenomas in 4129 patients. The inverted type and flat-elevated type were more frequent among SSA/Ps than among the other two types of serrated lesions. Magnifying colonoscopy revealed that a round and open pit pattern, expanded crypt openings and varicose microvascular vessels were more frequently observed among SSA/Ps than among the other types. The incidence of high-grade dysplasia or carcinoma among SSA/Ps (13.0%) was significantly higher than that among HPs (0%, P < 0.001) and equivalent to that among conventional adenomas (12.3%).

CONCLUSION

SSA/Ps have colonoscopic features distinct from those of HPs and TSAs. The malignant potential of SSA/Ps seems to be equal to that of conventional adenomas.

Synchronous Quadruple Primary Neoplasms: Colon Adenocarcinoma, Collision Tumor of Neuroendocrine Tumor and Schwann Cell Hamartoma and Sessile Serrated Adenoma of the Appendix

Quadruple synchronous primary neoplasms are very rare with only three cases reported in the English-speaking literature to date. Collision tumors are also rare entities, especially of the appendix. We herein report a case of synchronous quadruple primary neoplasm in a 95-year-old female. She was diagnosed with colon adenocarcinoma, sessile serrated adenoma of the appendix and a collision tumor composed of a well-differentiated neuroendocrine tumor and Schwann cell hamartoma. Histological examination and immunohistochemistry supported these four lesions as separate entities. This case is unique because we report the diagnosis of quadruple synchronous primary, an extremely rare occurrence, in addition to a collision tumor of the appendix. We also provide a review of the literature for synchronous neoplasms and collision tumors.

Confocal laser endomicroscopy features of sessile serrated adenomas/polyps

BACKGROUND AND AIMS

Sessile serrated adenomas/polyps (SSA/Ps) are difficult to differentiate from non-neoplastic tissue on white-light endoscopy. Confocal laser endomicroscopy (CLE) provides subcellular imaging and real-time "optical biopsy". The aim of this study was to prospectively describe CLE features of SSA/Ps.

PATIENTS AND METHODS

Consecutive patients with SSA/Ps were prospectively evaluated with probe-based CLE imaging. CLE images and polyp histology were independently reviewed by three endoscopists and an expert gastrointestinal (GI) pathologist. Distinguishing CLE features of SSA/Ps were identified in conjunction with pathologic correlation.

RESULTS

In total, 260 CLE images were generated from nine SSA/Ps evaluated in seven patients. Four consensus CLE features of SSA/P were identified: (1) a mucus cap with a bright, cloud-like appearance; (2) thin, branching crypts; (3) increased number of goblet cells and microvesicular mucin-containing cells; and (4) architectural disarray, with dystrophic goblet cells and lack of regular circular crypts.

CONCLUSION

This is a novel description of characteristic CLE features of SSA/Ps. The four features we identified are easy to detect and may allow for CLE to serve as a diagnostic modality.

Synchronous quadruple primary neoplasms: glioblastoma, neuroendocrine tumor, schwannoma and sessile serrated adenoma in a patient with history of prostate cancer

Quadruple synchronous primary neoplasms are exceedingly rare with only one case reported in the English literature. We herein report a case of synchronous quadruple primary neoplasms in a 70-year-old Arabic male with a history of prostate cancer who presented to our hospital for work-up of a brain mass found at an outside hospital. Subsequent (18)Fluorodeoxyglucose (FDG) positron emission tomography demonstrated a 5.9-cm temporoparietal mass and three additional lesions, each with increased maximum standardized uptake value (SUV(max)). Histologic examination, immunohistochemistry and cytogenetic analyses of the lesional tissue revealed four primary neoplastic lesions: primary glioblastoma, inguinal schwannoma, well-differentiated neuroendocrine tumor of the terminal ileum and an appendiceal sessile serrated adenoma/polyp. This case is unique among previous reports as our patient presented with four primary neoplasms synchronously. To the best of our knowledge, this combination of synchronous multiple primary neoplasms has not been reported in the English literature.

Diagnostic features of sessile serrated adenoma/polyps on magnifying narrow band imaging: a prospective study of diagnostic accuracy

BACKGROUND AND AIMS

The narrow band imaging classification system (NBI International Colorectal Endoscopic [NICE] classification) classifies colorectal polyps very accurately. However, sessile serrated adenoma/polyps (SSA/Ps) pathologically resembles hyperplastic polyp and has a possibility to be left in situ on NICE classification. The aim of this study was to establish and evaluate new simple diagnostic features for SSA/Ps using magnifying narrow band imaging (M-NBI).

METHODS

We performed a single-arm observational study of diagnostic accuracy in two stages, as follows: seeking stage, development of simple diagnostic features for SSA/P and definition of diagnostic criteria based on retrospective assessments of M-NBI; and validation stage, prospective validation and evaluation of the new diagnostic criteria.

RESULTS

In the seeking stage, we identified brownish, oval, expanded crypt openings and thick-branched vessels on the surfaces of SSA/Ps. We named these "expanded crypt openings" (ECOs) and "thick and branched vessels" (TBVs), respectively. In the validation stage, we enrolled 796 polyps in 261 patients, and classified 126 polyps as NICE type 1; all these lesions were endoscopically removed and assessed histopathologically. The sensitivity, specificity, and accuracy of ECOs for SSA/Ps were 84.3%, 81.1%, and 82.4%, whereas those of TBVs were 45.1%, 68.9%, and 59.2%, respectively. M-NBI provided a sensitivity of 98% and specificity of 59.5% for discrimination of SSA/Ps from other lesions classified as NICE type 1.

CONCLUSIONS

Identification of ECOs, supplemented with TBVs, has high sensitivity for the diagnosis of SSA/P. These findings may facilitate the use of endoscopic optical diagnosis in clinical practice.

Adenocarcinoma arising in small sessile serrated adenoma/polyp (SSA/P) of the colon: clinicopathological study of eight lesions

We reviewed the clinicopathological findings of eight cases of sessile serrated adenoma/polyps (SSA/Ps) with carcinoma, the largest diameter of which was 10 mm or less. All lesions were polyps located in the right side of the colon. Four lesions showed submucosal invasion and one lesion invaded the proper muscle layer. The depth of invasion, however, did not seem to be related to the carcinoma area size. Most carcinomas were well to moderately differentiated tubular adenocarcinomas focally showing some serrated appearances, and the predominant component of one carcinoma was a poorly differentiated medullary growth with inflammatory stroma. Rapid progression to invasive carcinoma from SSA/P was suggested for the carcinoma with proper muscle invasion whereas one submucosally invasive carcinoma was considered to progress over 7 years. Immunohistochemically, it was suggested that with or without hMLH1 protein loss, alterations of p53 and/or Wnt signaling pathway can be involved in the cancerization through SSA/Ps. The carcinomas irregularly imitated the mucin expression of the SSA/Ps (positive for MUC5AC and MUC2, and MUC6 expression in crypt bases), which was lost with progression of the carcinomas. Analyses of small SSA/P lesions with cancerization would facilitate the understanding of the mode of progression of SSA/Ps and their early detection.

Recommended intervals between screening and surveillance colonoscopies

Colonoscopy has become the mainstay for screening and surveillance of colorectal cancer. The guidelines for screening and surveillance colonoscopy have recently been updated, particularly in light of greater recognition of the importance of sessile serrated lesions in the role of cancer. It is important for practitioners to be aware of and understand the recommendations for screening and surveillance to optimize patient safety and to decrease health care use. We searched PubMed for articles and guidelines related to screening and surveillance of colonic polyps and serrated adenomas. The related citations feature was also used. The search was conducted from February 22, 2013, to March 2, 2013, and we included the search terms colorectal cancer screening, colonoscopy, guidelines, colorectal polyps, and colorectal surveillance. We selected the most recent guidelines and pertinent articles for this review, in which we discuss the basis of screening and surveillance colonoscopy and provide recommendations for colonoscopy intervals.

Differentiation between sessile serrated adenoma/polyp and non-sessile serrated adenoma/polyp in large hyper plastic polyp: A Japanese collaborative study

A hyperplastic polyp (HP) >10 mm is described as a large hyperplastic polyp (LHP). Previous studies have considered LHP and sessile serrated adenoma/polyp (SSA/P) as synonymous. Although HP and SSA/P have previously been morphologically distinguished, differences between LHP and SSA/P have not yet been reported. The present study aimed to define the differences between SSA/P and non-SSA/P in LHP using immunohistochemistry for Ki67. Colorectal serrated lesions (>10 mm) that were completely resected by endoscope and derived from 11 institutions in Japan [Dokkyo Medical University School of Medicine (Mibu), Takahiro Fujii Clinic (Tokyo), Sano Hospital (Kobe), Oda GI Clinic, Hattori GI Endoscopy and Oncology Clinic (Kumamoto), Ohta Clinic (Nagoya), Hiroshima University (Hiroshima), Iwate Medical University (Morioka), Juntendo and Kyorin Universities (Tokyo) as well as Toyama University (Toyama)] affiliated with the Japanese Society for Cancer of the Colon and Rectum (JSCCR) between January 2003 and December 2010 were selected. The histological criteria of the Japanese Society for Cancer of the Colon and Rectum (JSCCR, project meeting; editor-in chief, Takashi Yao) were used to distinguish SSA/P and non-SSA/P from LHP. Non-SSA/P comprises both incomplete SSA/P and HP. A total of 154 samples diagnosed as SSA/P or non-SSA/P from 148 patients were used. This study comprised 107 SSA/P and 47 non-SSA/P cases, whereby lesions were located on the right side of the colon (73.2 and 26.8%, respectively). Ki67-positivity in SSA/Ps was significantly higher compared to non-SSA/Ps. A greater number of SSA/Ps in LHP were located on the right side of the colon compared to the left side. SSA/Ps occurring on the right side of the colon may be precursor lesions of colorectal carcinoma in serrated neoplasia pathways. In conclusion, LHPs and SSA/Ps limited to the right side of the colon are suggested to be clinically treated as the same type of lesions.