Superficial Serrated Adenoma (SuSA): A New Subtype of Serrated Lesions

Superficial serrated adenoma (SuSA) is a new subtype of serrated lesions proposed in recent years, most of which are located in the sigmoid colon or rectum, with typical mixed adenoma and serrated pathological features, and its molecular features are high frequency of KRAS mutation and RSPO fusion or overexpression. At present, it is believed that SuSA has two subtypes: traditional serrated adenoma (TSA)-associated SuSA and isolated SuSA. Solitary SuSA showed faded pedicle-free protuberant lesions under endoscope and lobulated, pp (pit pattern) classification was type II and type IIIH, TSA-associated SuSA showed double-layer eminence, SuSA part showed white flat eminence, pp classification showed type II and IIIH, TSA part showed red tone high eminence, pp was IVH type. SuSA can develop into colorectal cancer through the evolution of TSA, and it can also directly develop into MSS colorectal cancer. In view of the superficial understanding of SuSA and the lack of a complete description of SuSA, this paper review the research progress of SuSA at home and abroad from the origin, endoscope features, histopathological features, molecular biology, differential diagnosis and treatment of SuSA, in order to better promote the understanding and clinical diagnosis of lesions.

Clinicopathological features and expression of regulatory mechanism of the Wnt signaling pathway in colorectal sessile serrated adenomas/polyps with different syndrome types

BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide,with the fourth highest mortality among all cancers.Reportedly,in addition to adenomas,serrated polyps,which account for 15%-30%of CRCs,can also develop into CRCs through the serrated pathway.Sessile serrated adenomas/polyps(SSAs/Ps),a type of serrated polyps,are easily misdiagnosed during endoscopy.AIM To observe the difference in the Wnt signaling pathway expression in SSAs/Ps patients with different syndrome types.METHODS From January 2021 to December 2021,patients with SSAs/Ps were recruited from the Endoscopy Room of Shanghai Traditional Chinese Medicine-Integrated Hospital,affiliated with Shanghai University of Traditional Chinese Medicine.Thirty cases each of large intestine damp-heat(Da-Chang-Shi-Re,DCSR)syndrome and spleen-stomach weakness(Pi-Wei-Xu-Ruo)syndrome were reported.Baseline comparison of the general data,typical tongue coating,colonoscopy findings,and hematoxylin and eosin findings was performed in each group.The expression of the Wnt pathway-related proteins,namelyβ-catenin,adenomatous polyposis coli,and mutated in colorectal cancer,were analyzed using immunohistochemistry.RESULTS Significant differences were observed with respect to the SSAs/Ps size between the two groups of patients with different syndrome types(P=0.001).The other aspects did not differ between the two groups.The Wnt signaling pathway was activated in patients with SSAs/Ps belonging to both groups,which was manifested asβ-catenin protein translocation into the nucleus.However,SSAs/Ps patients with DCSR syndrome had more nucleation,higherβ-catenin expression,and negative regulatory factor(adenomatous polyposis coli and mutated in colorectal cancer)expression(P<0.0001)than SSA/P patients with Pi-Wei-Xu-Ruo syndrome.In addition,the SSA/P size was linearly correlated with the related protein expression.CONCLUSION Patients with DCSR syndrome had a more obvious Wnt signaling pathway activation and a higher risk of carcinogenesis.A high-quality colonoscopic diagnosis was essential.The thorough assessment of clinical diseases can be improved by combining the diseases of Western medicine with the syndromes of traditional Chinese medicine.

Sessile serrated adenomas:Demographic,endoscopic and pathological characteristics

AIM:To study the demographic and endoscopic characteristics of patients with sessile serrated adenoma(SSA) in a single center.METHODS:Patients with SSA were identified by review of the pathology database of Mayo Clinic Arizona from 2005 to 2007.A retrospective chart review was performed to extract data on demographics,polyp characteristics,presence of synchronous adenomatous polyps or cancer,polypectomy methods,and related complications.RESULTS:One hundred and seventy-one(2.9%) of all patients undergoing colonoscopy had a total of 226 SSAs.The mean(SE) size of the SSAs was 8.1(0.4) mm;42% of SSAs were ≤ 5 mm,and 69% were ≤ 9 mm.Fifty-one per cent of SSAs were located in the cecum or ascending colon.Approximately half of the patients had synchronous polyps of other histological types,including hyperplastic and adenomatous polyps.Synchronous adenocarcinoma was present in seven(4%) cases.Ninety-seven percent of polyps were removed by colonoscopy.CONCLUSION:Among patients with colon polyps,2.9% were found to have SSAs.Most of the SSAs were located in the right side and were safely managed by colonoscopy.

Correlations of morphology and molecular alterations in traditional serrated adenoma

Traditional serrated adenoma was first reported by Longacre and FenoglioPresier in 1990.Their initial study described main features of this lesion,but the consensus diagnostic criteria were not widely adopted until recently.Traditional serrated adenoma presents with grossly protuberant configuration and pineconelike appearance upon endoscopy.Histologically,it is characterized by ectopic crypt formation,slit-like serration,eosinophilic cytoplasm and pencillate nuclei.Although much is now known about the morphology and molecular changes,the mechanisms underlying the morphological alterations are still not fully understood.Furthermore,the origin of traditional serrated adenoma is not completely known.We review recent studies of the traditional serrated adenoma and provide an overview on current understanding of this rare entity.

Improving sessile serrated adenoma detection rates with high definition colonoscopy:A retrospective study

BACKGROUND Sessile serrated adenomas(SSAs)are important premalignant lesions that are difficult to detect during colonoscopy due to poor definition,concealment by mucous caps,and flat appearance.High definition(HD)colonoscopy may uniquely aid in the detection of these inconspicuous lesions compared to standard definition(SD)colonoscopes.In the absence of existing clinical guidelines to obligate the use of HD colonoscopy for colorectal cancer screening in average-risk patients,demonstrating the benefit of HD colonoscopy on SSA detection rate(SSADR)may help strengthen the evidence to recommend its use in all settings.AIM To evaluate the benefit of HD colonoscopy compared to SD colonoscopy on SSADR in average-risk patients undergoing screening colonoscopy.METHODS Data from screening colonoscopies for patients aged 50-76 years two years before and two years after the transition from SD colonoscopy to HD colonoscopy at our large,academic teaching center were collected.Patients with symptoms of colorectal disease,positive occult blood test,history of colon polyps,cancer,polyposis syndrome,inflammatory bowel disease or family history of colon cancer or polyps were excluded.Patients whose endoscopists did not perform colonoscopies both before and after scope definition change were also excluded.Differences in individual endoscopist SSADR,average SSADR,and overall SSADR with SD colonoscopy vs HD colonoscopy were also evaluated for significance.RESULTS A total of 3657 colonoscopies met eligibility criteria with 2012 colonoscopies from the SD colonoscopy period and 1645 colonoscopies from the HD colonoscopy period from a pool of 11 endoscopists.Statistically significant improvements of 2.30%in mean SSADR and 2.53%in overall SSADR were noted with HD colonoscopy(P=0.00028 and P=0.00849,respectively).On the individual level,three endoscopists experienced statistically significant benefit with HD colonoscopy(+5.74%,P=0.0056;+4.50%,P=0.0278;+4.84%,P=0.03486).CONCLUSION Our study suggests that HD colonoscopy statistically significantly improves sessile serrated adenoma detection rate in the screening of average risk patients during screening colonoscopy.By improving the detection and removal of these lesions,adoption of HD colonoscopy may reduce the significant premalignant burden of sessile serrated adenomas.

Significance of EZH2 and BMI-1 Protein Expression in Carcinogenesis of Colon Serrated Adenoma

Objective:To observe the significance of EZH2 and BMI-1 protein expression in the carcinogenesis process of colon serrated adenoma(SSA/P).Methods:Hematoxylin-eosin(HE)staining was used to observe the morphological characteristics of normal tissues,hyperplastic polyp(HP),SSA/P and colon cancer.Immunohistochemical staining was used to detect the expression of EZH2 and BMI-1 protein.The relative expression of EZH2 and BMI-1 was detected by qRT-PCR.Results:Compared with normal tissues,HP and colon cancer tissues,SSA/P showed serrated glandular hyperplasia,glandular dilatation,and deep nuclear staining,which had certain atypia.The positive expression rates of EZH2 and BMI-1 protein were 53.3%and 56%,which were close to those of colon cancer(66.7% and 76.6%)and higher than those of normal group and HP(16% and 8%,P<0.05).The relative expression of EZH2 and BMI-1 in SSA/P tissue was significantly higher than that in normal group and HP,but lower than that in carcinogenesis group(P<0.05).Conclusion:EZH2 and BMI-1 play an important role in the carcinogenesis of colon serrated adenoma,and can be used as the primary screening index before carcinogenesis.

Serrated polyps of the colon and rectum:Remove or not?

In recent years,the serrated neoplasia pathway where serrated polyps arise as a colorectal cancer has gained considerable attention as a new carcinogenic pathway.Colorectal serrated polyps are histopathologically classified into hyperplastic polyps(HPs),sessile serrated lesions,and traditional serrated adenomas;in the serrated neoplasia pathway,the latter two are considered to be premalignant.In western countries,all colorectal polyps,including serrated polyps,apart from diminutive rectosigmoid HPs are removed.However,in Asian countries,the treatment strategy for colorectal serrated polyps has remained unestablished.Therefore,in this review,we described the clinicopathological features of colorectal serrated polyps and proposed to remove HPs and sessile serrated lesions≥6 mm in size,and traditional serrated adenomas of any size.

Serrated lesions:A challenging enemy

The serrated pathway accounts for 30%-35%of colorectal cancer(CRC).Unlike hyperplastic polyps,both sessile serrated lesions(SSLs)and traditional serrated adenomas are premalignant lesions,yet SSLs are considered to be the principal serrated precursor of CRCs.Serrated lesions represent a challenge in detection,classification,and removal–contributing to post-colonoscopy cancer.Therefore,it is of the utmost importance to characterize these lesions properly to ensure complete removal.A retrospective cohort study developed a diagnostic scoring system for SSLs to facilitate their detection endoscopically and subsequent removal.From the study,it can be ascertained that both indistinct border and mucus cap are essential in both recognizing and diagnosing serrated lesions.The proximal colon poses technical challenges for some endoscopists,which is why high-quality colonoscopy plays such an important role.The indistinct border of some SSLs poses another challenge due to difficult complete resection.Overall,it is imperative that gastroenterologists use the key features of mucus cap,indistinct borders,and size of at least five millimeters along with a high-quality colonoscopy and a good bowel preparation to improve the SSL detection rate.

Detection Rate, Distribution, Clinical and Pathological Features of Colorectal Serrated Polyps

Background：Colorectal serrated polyp is considered as histologically heterogeneous lesions with malignant potential in western countries.However,few Asian studies have investigated the comprehensive clinical features of serrated polyps in symptomatic populations.The aim of the study was to evaluate the features of colorectal serrated polyps in a Chinese symptomatic population.Methods：Data from all consecutive symptomatic patients were documented from a large colonoscopy database and were analyzed.Chi-square test or Fisher＇s exact test and logistic regression analysis were used for the data processing.Results：A total of 9191 （31.7%） patients were detected with at least one colorectal polyp.The prevalence of serrated polyps was 0.53% （153/28,981）.The proportions of hyperplastic polyp （HP）,sessile serrated adenoma/polyp （SSA/P）,and traditional serrated adenoma （TSA） of all serrated polyps were 41.2%,7.2%,and 51.6%,respectively,which showed a lower proportion of HP and SSA/P and a higher proportion of TSA.Serrated polyps appeared more in males and elder patients while there was no significant difference in the subtype distribution in gender and age.The proportions of large and proximal serrated polyps were 13.7% （21/153） and 46.4% （71/153）,respectively.In total,98.9% （89/90） serrated adenomas were found with dysplasia.Moreover,14 patients with serrated polyps were found with synchronous advanced colorectal neoplasia,and large serrated polyps （LSPs） （odds ratio：3.446,95% confidence interval：1.010-11.750,P 〈 0.05）,especially large HPs,might have an association with synchronous advanced neoplasia （AN）.Conclusions：The overall detection rate ofcolorectal serrated polyps in Chinese symptomatic patient population was low,and distribution pattern of three subtypes is different from previous reports.Moreover,LSPs,especially large HPs,might be associated with an increased risk of synchronous AN.