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.

Effective use of the Japan Narrow Band Imaging Expert Team classification based on diagnostic performance and confidence level

Five years have passed since the Japan Narrow Band Imaging Expert Team (JNET) classification was proposed in 2014. However, the diagnostic performance of this classification has not yet been established. We conducted a retrospective study and a systematic search of Medical Literature Analysis and Retrieval System On-Line. There were three retrospective single center studies about the diagnostic performance of this classification. In order to clarify this issue, we reviewed our study and three previous studies. This review revealed the diagnostic performance in regards to three important differentiations.(1) Neoplasia from non-neoplasia;(2) malignant neoplasia from benign neoplasia;and (3) deep submucosal invasive cancer (D-SMC) from other neoplasia. The sensitivity in differentiating neoplasia from non-neoplasia was 98.1%-99.8%. The specificity in differentiating malignant neoplasia from benign neoplasia was 84.7%-98.2% and the specificity in the differentiation D-SMC from other neoplasia was 99.8%-100.0%. This classification would enable endoscopists to identify almost all neoplasia, to appropriately determine whether to perform en bloc resection or not, and to avoid unnecessary surgery. This article is the first review about the diagnostic performance of the JNET classification. Previous reports about the diagnostic performance have all been retrospective single center studies. A large-scale prospective multicenter evaluation study is awaited for the validation.

Prospective real-time evaluation of diagnostic performance using endocytoscopy in differentiating neoplasia from nonneoplasia for colorectal diminutive polyps(≤ 5 mm)

AIM To clarify the diagnostic performance of endocytoscopy for differentiation between neoplastic and nonneoplastic colorectal diminutive polyps.METHODS Patients who underwent endocytoscopy between October and December 2016 at Sano Hospital were prospectively recruited. When diminutive polyps(≤5 mm) were detected, the lesions were evaluated by endocytoscopy after being stained with 0.05% crystal violet and 1% methylene blue. The diminutivepolyps were classified into five categories(EC 1 a, 1 b, 2, 3 a, and 3 b). Endoscopists were asked to take a biopsy from any lesion diagnosed as EC1 b(indicator of hyperplastic polyp) or EC2(indicator of adenoma). We have assessed the diagnostic performance of endocytoscopy for EC2 and EC1 b lesions by comparison with the histopathology of the biopsy specimen. RESULTS A total of 39 patients with 63 diminutive polyps were analyzed. All polyps were evaluated by endocytoscopy. The mean polyp size was 3.3 ± 0.9 mm. Among the 63 diminutive polyps, 60 were flat and 3 were pedunculated. The mean time required for EC observation, including the time for staining with crystal violet and methylene blue, was 3.0 ± 1.9 min. Histopathologic evaluation showed that 13 polyps were hyperplastic and 50 were adenomas. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of EC2 for adenoma compared with EC1 b for hyperplastic polyp were 98.0%, 92.3%, 96.8%, 98.0% and 92.3%, respectively. There were only two cases of disagreement between the endoscopic diagnosis made by endocytoscopy and the corresponding histopathological diagnosis.CONCLUSION Endocytoscopy showed a high diagnostic performance for differentiating between neoplastic and non-neoplastic colorectal diminutive polyps, and therefore has the potential to be used for "real-time histopathology".

Sporadic fundic gland polyps with dysplasia or carcinoma:Clinical and endoscopic characteristics

Fundic gland polyps(FGPs)are the most common gastric polyps and have been regarded as benign lesions with little malignant potential,except in the setting of familial adenomatous polyposis.However,in recent years,the prevalence of FGPs has been increasing along with the widespread and frequent use of proton pump inhibitors(PPIs).To date,several cases of FGPs with dysplasia or carcinoma(FGPD/CAs)have been reported.In this review,we evaluated the clinical and endoscopic characteristics of sporadic FGPD/CAs.Majority of the patients with sporadic FGPD/CAs were middle-aged women receiving PPI therapy and without Helicobacter pylori(H.pylori)infection.Majority of the sporadic FGPD/CAs occurred in the body of the stomach and were sessile and small with a mean size of 5.4 mm.The sporadic FGPs with carcinoma showed redness,irregular surface structure,depression,or erosion during white light observation and irregular microvessels on the lesion surface during magnifying narrow-band imaging.In addition,sporadic FGPs,even with dysplasia,are likely to progress to cancer slowly.Therefore,frequent endoscopy is not required for patients with sporadic FGPs.However,histopathological evaluation is necessary if endoscopic findings different from ordinary FGPs are observed,regardless of their size.In the future,the prevalence of FGPs is expected to further increase along with the widespread and frequent use of PPIs and decreasing infection rate of H.pylori.Currently,it is unclear whether FGPD/CAs will also increase in the same way as FGPs.However,the trends of these lesions warrant further attention in the future.

New application of endocytoscope for histopathological diagnosis of colorectal lesions

BACKGROUND The endocytoscope with ultra-high magnification(x 520)allows us to observe the cellular structure of the colon epithelium during colonoscopy,known as virtual histopathology.We hypothesized that the endocytoscope could directly observe colorectal histopathological specimens and store them as endocyto-pathological images by the endoscopists without a microscope,potentially saving the burden on histopathologists.AIM To assess the feasibility of endocyto-pathological images taken by an endoscopist as adequate materials for histopathological diagnosis.METHODS Three gastrointestinal pathologists were invited and asked to diagnose 40 cases of endocyto-pathological images of colorectal specimens.Each case contained seven endocyto-pathological images taken by an endoscopist,consisting of one loupe image,three low-magnification images,and three ultra-high magnification images.The participants chose hyperplastic polyp or low-grade adenoma for 20 cases of endocyto-pathological images(10 hyperplastic polyps,and 10 Low-grade adenomas in conventional histopathology)in study 1 and high-grade adenoma/shallow invasive cancer or deep invasive cancer for 20 cases[10 tumor in situ/T1a and 10 T1b]in study 2.We investigated the agreement between the histopathological diagnosis using the endocyto-pathological images and conventional histopathological diagnosis.RESULTS Agreement between the endocyto-pathological and conventional histopathological diagnosis by the three gastrointestinal pathologists was 100%(95%CI:94.0%–100%)in studies 1 and 2.The interobserver agreement among the three gastrointestinal pathologists was 100%,and theκcoefficient was 1.00 in both studies.CONCLUSION Endocyto-pathological images were adequate and reliable materials for histopathological diagnosis.