Effect of cognitive load and working memory capacity on the efficiency of discovering better alternatives: A survival analysis.

Why do humans attempt to discover better alternatives to solve a problem even when they know the way to solve it? This question is related to the flexibility of thinking and is the subject of studies on the Einstellung effect. This study focuses on cognitive load for familiar trained procedure as a factor that influences the discovery of alternatives in Einstellung situations, where the problem can be solved using a trained procedure. Many studies on creative problem solving and strategy selection demonstrate that cognitive load for facilitates the discovery of alternatives. However, findings are inconsistent regarding Einstellung situations. We argue that the reason for such inconsistent results were the use of manipulations such as the double task, which both load on the trained and alternative procedure and the lack of perspective on efficiency in analysis. Therefore, we examine the relationship between cognitive load manipulated by the complexity of the trained procedure and time-based performance measured by the number of trials prior to finding alternatives. The results illustrate that higher cognitive load increased the efficiency of discovery of alternatives and that this effect was significant for participants with high working memory capacity. This study provides empirical evidence that high cognitive load for trained procedure facilitates the discovery of alternatives and suggests the importance of considering temporal properties, such as efficiency, when examining the effects of working memory on problem solving, which requires cognitive flexibility.

Performance evaluation of a computer-aided polyp detection system with artificial intelligence for colonoscopy.

OBJECTIVES: A computer-aided detection (CAD) system was developed to support the detection of colorectal lesions by deep learning using video images of lesions and normal mucosa recorded during colonoscopy. The study's purpose was to evaluate the stand-alone performance of this device under blinded conditions. METHODS: This multicenter prospective observational study was conducted at four Japanese institutions. We used 326 videos of colonoscopies recorded with patient consent at institutions in which the Ethics Committees approved the study. The sensitivity of successful detection of the CAD system was calculated using the target lesions, which were detected by adjudicators from two facilities for each lesion appearance frame; inconsistencies were settled by consensus. Successful detection was defined as display of the detection flag on the lesion for more than 0.5 s within 3 s of appearance. RESULTS: Of the 556 target lesions from 185 cases, detection success sensitivity was 97.5% (95% confidence interval [CI] 95.8-98.5%). The "successful detection sensitivity per colonoscopy" was 93% (95% CI 88.3-95.8%). For the frame-based sensitivity, specificity, positive predictive value, and negative predictive value were 86.6% (95% CI 84.8-88.4%), 84.7% (95% CI 83.8-85.6%), 34.9% (95% CI 32.3-37.4%), and 98.2% (95% CI 97.8-98.5%), respectively. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN000044622).

H3 K27-altered diffuse midline glioma in adults arising from atypical regions: Two case reports and literature review.

Diffuse midline glioma (DMG), H3 K27-altered, is a newly defined "pediatric-type," diffuse, high-grade glioma under current WHO classifications (updated in 2021). An essential diagnostic criteria of DMG is its occurrence in the midline structures; most intracranial DMG occurs in the brainstem or thalamus but can also occur in other midline structures. We experienced 2 adult cases of intracranial DMGs in areas other than the brainstem and thalamus that were initially difficult to diagnose. Case 1 was a 49-year-old man with extensive T2 high-signal lesions in the bilateral frontal lobes and corpus callosum on brain MRI. A Gd-based contrast medium partially enhanced the lesion and showed marked diffusion restriction, mimicking malignant lymphoma. Case 2 was a 24-year-old man who presented with paroxysmal olfactory abnormalities. The tumor extended mainly to the right temporal lobe, the right basal forebrain, and the bilateral hypothalamus, showing a T2/FLAIR mismatch sign suggestive of IDH-mutant astrocytoma without 1p/19q co-deletion. After a biopsy, both cases were properly diagnosed as DMG, H3 K27-altered (K27M-mutant). Diagnosing adult cases involving atypical midline structures is sometimes challenging before surgery; we discuss this phenomenon with both case details and a literature review.

Differences in the distribution of attention to trained procedure between finders and non-finders of the alternative better procedure.

The human ability to flexibly discover alternatives without fixating on a known solution supports a variety of human creative activities. Previous research has shown that people who discover an alternative procedure relax their attentional bias to information regarding the known solutions just prior to the discovery. This study examined whether the difference in the distribution of attention between the finders and non-finders of the alternative procedure is observed from the phase of solving the problem using the trained procedure. We evaluated the characteristics of the finders' distribution of attention in situations where problem solving using a trained procedure was successful. This aspect has been little examined in previous research. Our study obtained empirical evidence for the fact that, compared to non-finders, finders pay more attention to information unrelated to the trained procedure acquired through knowledge and experience, even time when using a trained procedure. We also confirmed that this difference does not exist from the beginning of the task, but emerges during repeated use of familiar procedures. These findings indicate that in order to find an alternative procedure, one should not only divert attention from a familiar procedure just before the discovery but also pay a certain amount of attention to information unrelated to the familiar procedure even when the familiar procedure is functioning well.

Self-Benefit and Others' Benefit in Cooperative Behavior in Shared Space.

OBJECTIVE: The objective is to clarify the nature of cooperative moving behavior that realizes smooth traffic with others from the viewpoint of the trade-off between self-benefit and others' benefit in the shared space. BACKGROUND: The shared space is not constrained by formal rules or behavioral norms, and is a potentially ambiguous situation where it is not clear who has priority. Therefore, the nature of cooperative behavior in the shared space is unclear. METHOD: An experimental task was conducted to compare cooperative and nonurgent moving behavior regarding completion time (self-benefit), the amount of interruption (others' benefit), and the amount of operation (cognitive effort). RESULTS: First, cooperative behavior benefits others. Second, although cooperative behavior decreases self-benefit compared to the baseline without any instructions, it can obtain relatively more self-benefit than nonurgent behavior without considering self-benefit. Third, cooperative behavior requires cognitive effort. CONCLUSION: Cooperative behavior provides benefit to both oneself and others by spending cognitive effort in not interrupting others. APPLICATION: If the nature of the cooperative behavior can be clarified, a cooperative module can be implemented into the algorithms of various mobilities.

Comparison of the diagnostic performance of NBI, Laser-BLI and LED-BLI: a randomized controlled noninferiority trial.

BACKGROUND AND AIMS: New image-enhanced endoscopy (IEE), blue Light Imaging (LED-BLI) is launched in USA and Europe, whereas Blue Laser Imaging (Laser-BLI) is available only Asian and some countries. No studies have directly compared the diagnostic accuracy of narrow band imaging (NBI), Laser-BLI and LED-BLI for colorectal tumors. The present study aimed to compare the diagnostic accuracy of the three methods for colorectal tumor using the NBI international colorectal endoscopic (NICE) classification and the Japanese NBI Expert Team (JNET) classifications. METHODS: This was a multi-center evaluator-blinded, randomized control trial of patients who underwent endoscopic colorectal tumor resection. The patients were randomly assigned to NBI, Laser-BLI or LED-BLI. Cropped images were sent to blinded external evaluators and diagnosed according to NICE and JNET classifications. The diagnostic accuracy of each endoscopy system was compared with non-inferiority test. RESULTS: A total of 619 colonic tumors were resected from 230 patients and evaluated by external four evaluators. The diagnostic accuracy of NBI for NICE 1, NICE 2, NICE 3 was 90.6%, 90.3% and 99.5%, respectively and for JNET 1, JNET 2A, JNET 2B and JNET 3, it was 94.6%, 72.0%, 79.2% and 99.1%, respectively. In non-inferiority test, Laser-BLI and LED-BLI revealed non-inferiority to NBI in all NICE and JNET categories (p<0.001). CONCLUSIONS: Laser-BLI and LED-BLI had high diagnostic accuracy and non-inferiority of NBI, especially for hyperplastic polyp/sessile serrated lesion and low-grade dysplasia. This is first trial to compare the diagnostic accuracy with NBI, Laser-BLI and LED-BLI and useful to understand the position of each IEE. This trial was registered as UMIN000032107.

Prognosis after curative resection for stage IA gastric cancer in elderly patients: endoscopic submucosal dissection versus surgery.

PURPOSE: To establish whether gastrectomy for early gastric cancer (EGC) in elderly patients is related to poor survival. METHODS: The subjects of this retrospective study were patients aged ≥ 75 years with primary stage IA EGC, who underwent curative resection with endoscopic submucosal dissection (ESD) or surgery. RESULTS: We analyzed data on 365 patients who underwent ESD and 170 patients who underwent surgery. Overall survival (OS) was not significantly different for the ESD group vs. the surgery group (5-year cumulative rates, 81.5% vs. 79.7%; log-rank test, P = 0.506). Multivariate analysis revealed that treatments; namely, ESD or surgery, were not associated with OS (hazard ratio 1.09, 95% confidence interval 0.77-1.51). Similar results were observed even in the subgroups with worse conditions, such as age > 80 years, Eastern Cooperative Oncology Group performance status 2-3, Charlson comorbidity index ≥ 2, and prognostic nutritional index ≤ 46.7. Using propensity score matching, we selected 88 pairs of patients who underwent ESD or surgery with baseline characteristics matched and found that OS was not different between the two groups (log-rank test, P = 0.829). CONCLUSION: OS was comparable for elderly patients who underwent ESD and those who underwent surgery for EGC. Surgical invasiveness did not worsen the prognosis, even for elderly patients.

Long-term prognosis after endoscopic submucosal dissection for colorectal tumors in patients aged over 80 years.

BACKGROUND: In Japan, endoscopic submucosal dissection (ESD) is standardized for large colorectal tumors. However, its validity in the elderly population is unclear. We aimed to evaluate the safety and efficacy of ESD for colorectal tumors in elderly patients aged over 80 years. METHODS: ESD was performed on 178 tumors in 165 consecutive patients aged over 80 years between December 2008 and December 2018. We retrospectively evaluated the clinicopathological characteristics and clinical outcomes of ESD. We also assessed the prognosis of 160 patients followed up for more than 12 months. RESULTS: The mean patient age was 83.7 ± 3.1 years. The number of patients with comorbidities was 100 (62.5%). Among all patients, 106 (64.2%) were categorized as class 1 or 2 according to the American Society of Anesthesiologists classification of physical status (ASA-PS), and 59 (35.8%) were classified as class 3. The mean procedure time was 97.7 ± 79.3 min. The rate of histological en bloc resection was 93.8% (167/178). Delayed bleeding in 11 cases (6.2%) and perforation in 7 cases (3.9%) were treated conservatively. The 5-year survival rate was 89.9%. No deaths from primary disease (mean follow-up time: 35.3 ± 27.5 months) were observed. Overall survival rates were significantly lower in the non-curative resection group that did not undergo additional surgery than in the curative resection group (P = 0.0152) and non-curative group that underwent additional surgery (P = 0.0259). Overall survival rates were higher for ASA-PS class 1 or 2 patients than class 3 patients (P = 0.0105). Metachronous tumors (> 5 mm) developed in 9.4% of patients. CONCLUSIONS: ESD for colorectal tumors in patients aged over 80 years is safe. Colorectal cancer-associated deaths were prevented although comorbidities pose a high risk of poor prognosis.

Clinical usefulness of combination therapy with polidocanol injection and argon plasma coagulation for gastric antral vascular ectasia.

BACKGROUND AND AIM: Gastric antral vascular ectasia (GAVE) causes gastrointestinal bleeding. The initial treatment for GAVE bleeding is endoscopic hemostasis, and currently, the most performed technique to achieve hemostasis is argon plasma coagulation (APC). However, APC is associated with a high recurrence rate. To overcome this limitation, we examined the outcomes of the combination therapy of APC and polidocanol injection (PDI) for treating GAVE. METHODS: We retrospectively analyzed the outcomes of 15 consecutive GAVE patients treated with PDI + APC at Hiroshima University Hospital between November 2011 and September 2019 with respect to clinical characteristics, hemostatic efficacy, complications related to treatment, and recurrence rate. RESULTS: The mean age of patients (4 men and 11 women) was 74 ± 8.4 years. Patients had comorbidities of liver cirrhosis (seven patients, 47%), chronic renal failure (seven patients, 47%), and autoimmune diseases (seven patients, 47%). Endoscopic hemostasis with PDI + APC was performed in all patients (n = 15). The mean number of PDIs attempted to stop bleeding was 1.5 ± 0.8 (1-4), and the mean number of APCs attempted was 2.1 ± 1.2 (1-5). Complications related to treatment occurred in two patients (14%): ulceration in one patient and hematoma in another patient, both of whom were treated conservatively. Two patients (13%) had recurrences during the follow-up period (average period, 42 months). Both were cured with additional treatment of PDI only. CONCLUSION: The combination therapy of PDI and APC is effective for GAVE with a low recurrence rate.

Effect of educational lecture on the diagnostic accuracy of Japan NBI Expert Team classification for colorectal lesions.

BACKGROUND: An educational and training program is required for generalization of Japan NBI Expert Team (JNET) classification. However, there is no detailed report on the learning curve of the diagnostic accuracy of endoscopists using JNET classification. We examined the effect of an educational lecture on beginners and less experienced endoscopists for improving their diagnostic accuracy of colorectal lesions by JNET classification. METHODS: Seven beginners with no endoscopy experience (NEE group), 7 less experienced endoscopists (LEE group), and 3 highly experienced endoscopists (HEE group) performed diagnosis using JNET classification for randomized NBI images of colorectal lesions from 180 cases (Type 1: 22 cases, Type 2A: 105 cases, Type 2B: 33 cases, and Type 3: 20 cases). Next, the NEE and LEE groups received a lecture on JNET classification, and all 3 groups repeated the diagnostic process. We compared the correct diagnosis rate and interobserver agreement before and after the lecture comprehensively and for each JNET type. RESULTS: In the HEE group, the correct diagnosis rate was more than 90% with good interobserver agreements (kappa value: 0.78-0.85). In the NEE and LEE groups, the correct diagnosis rate (NEE: 60.2 → 68.0%, P < 0.01; LEE: 66.4 → 86.7%, P < 0.01), high-confidence correct diagnosis rate (NEE: 19.6 → 37.2%, P < 0.01; LEE: 43.6 → 61.1%, P < 0.01), and interobserver agreement (kappa value, NEE: 0.32 → 0.43; LEE: 0.39 → 0.75) improved after the lecture. In the examination by each JNET type, the specificity and positive predictive value in the NEE and LEE groups generally improved after the lecture. CONCLUSION: After conducting an appropriate lecture, the diagnostic ability using JNET classification was improved in beginners or endoscopists with less experience in NBI magnifying endoscopy.

Clinical usefulness of linked color imaging for evaluation of endoscopic activity and prediction of relapse in ulcerative colitis.

PURPOSE: In the treatment of ulcerative colitis (UC), accurate evaluation of UC activity is important to achieve mucosal healing. We sought to investigate the clinical utility of linked color imaging (LCI) for the evaluation of endoscopic activity and prediction of relapse in UC patients. METHODS: We enrolled 72 consecutive UC patients in remission who underwent colonoscopy at our institution between September 2016 and October 2018. The relationship between the presence of redness in white light imaging (WLI) and LCI and histopathological inflammation (Geboes score: GS) at 238 biopsy sites was examined. We also assessed the presence or absence of planar redness in the entire rectum as ± and classified the patients into three groups according to the combination of WLI/LCI: A: WLI-/LCI-, B: WLI-/LCI+, and C: WLI+/LCI+. The relationship between WLI/LCI classification and relapse in 64 patients followed up for more than 12 months from initial colonoscopy was assessed and compared to the Mayo endoscopic subscore (MES). RESULTS: A GS of 0 or 1 accounted for 89% of WLI/LCI non-redness sites, while a GS of 2 or 3 accounted for 42% of WLI non-redness/LCI redness sites. LCI findings were significantly correlated with GS. During follow-up, 10 patients in group C and four patients in group B relapsed, but none in group A. Non-relapse rates were significantly correlated with WLI/LCI classification, but not with MES. CONCLUSION: LCI is a useful modality for accurate assessment of endoscopic activity and prediction of relapse in UC by detecting mild inflammation unrecognizable by WLI.

Long-Term Outcomes after Endoscopic Submucosal Dissection for Ulcerative Colitis-Associated Dysplasia.

INTRODUCTION: The Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients: International Consensus Recommendations guidelines recommend surveillance colonoscopy instead of colectomy after the complete removal of "endoscopically resectable" dysplastic lesions in ulcerative colitis (UC). There are no studies on long-term outcomes of endoscopic submucosal dissection (ESD) for UC-associated neoplasia (UCAN). We aimed to evaluate the clinical outcomes of ESD for UC-associated dysplasia (UCAD) during long-term follow-up. METHODS: We retrospectively enrolled 17 consecutive UC patients with 22 UCADs, who underwent initial ESD or total proctocolectomy at the Hiroshima University Hospital. The clinicopathological features of the patients and neoplasias and clinical outcomes of ESD were evaluated and compared with those of total proctocolectomy. RESULTS: UCAD in the ESD and total proctocolectomy groups was mostly noted on the left side of the colon, and most lesions were superficial macroscopic lesions. In the ESD group, en bloc resection and histological complete resection rates were 83 and 67%, respectively. One patient died of malignant melanoma; however, none of the patients died of UC-associated carcinoma in both groups. Metachronous neoplasias developed in 5 of the 7 patients in the ESD group. Among the 5 patients with metachronous UCAN, 4 finally underwent total proctocolectomy and 1 underwent additional ESD. CONCLUSIONS: ESD for UCAD is a useful method for total excisional biopsy. UC patients with UCAD resected by ESD have a high risk of developing metachronous UCAN during the follow-up period.

Clinical significance of immunohistochemical lymphovascular evaluation to determine additional surgery after endoscopic submucosal dissection for colorectal T1 carcinoma.

PURPOSE: The Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines indicate lymphovascular invasion-evaluated by hematoxylin and eosin (HE) staining-as a surgical requirement after endoscopic submucosal dissection (ESD) in T1 colorectal carcinoma (CRC) patients; however, immunohistochemical evaluation may be superior. This study aimed to clarify the significance of immunohistochemical lymphovascular evaluation as an indicator for additional surgery of T1 CRC after ESD, and assessed the guidelines' adequacy, even when evaluating through immunostaining. METHODS: Patients with T1 CRC who underwent ESD were enrolled across three institutions between January 2012 and December 2017. Immunohistochemical lymphovascular evaluation was performed. Clinicopathological features, pathological evaluations, and surgery indications were recorded. Univariate and multivariate logistic regression identified risk factors for lymph node (LN) metastasis of T1 CRC after ESD. RESULTS: Among 370 patients with T1 CRC, recurrence, 5-year overall survival, and 5-year disease specific survival rates were 1.6%, 94.6%, and 99.5%, respectively. Six patients (1.6%) experienced recurrence, five of whom underwent additional surgery. Those with no risk factors did not exhibit recurrence. A total of 215 (58.1%) patients underwent additional surgery after ESD, 21 (9.7%) of whom exhibited LN metastasis. Among 16 patients who underwent additional surgery due to lymphovascular invasion, three (18.8%) had LN metastasis. Multivariate logistic regression analysis identified lymphatic invasion as a significant risk factor for LN metastasis (odds ratio 3.9, 95% confidence interval 1.0-14.6, P = 0.0421). CONCLUSIONS: The JSCCR guidelines have clinical validity, and immunohistochemical lymphatic evaluation findings potentially predict LN metastasis for T1 CRC after ESD.

Clinical Features and Genomic Characterization of Post-Colonoscopy Colorectal Cancer.

INTRODUCTION: Some colorectal cancers (CRCs) may be missed during colonoscopies. We aimed to determine the clinicopathological, biological, and genomic characteristics of post-colonoscopy CRCs (PCCRCs). METHODS: Of the 1,619 consecutive patients with 1,765 CRCs detected between 2008 and 2016, 63 patients with 67 PCCRCs, when colonoscopies were performed 6-60 months before diagnosis, were recruited. After excluding patients with inflammatory bowel disease, familial polyposis syndrome, CRCs that developed from diminutive adenomatous polyps, and recurrent CRCs after endoscopic resection, 32 patients with 34 PCCRCs were enrolled. The lesions' clinicopathological features, mismatch repair proteins (MMRs), and genomic alterations were investigated. RESULTS: The overall PCCRC-5y rate, rate of intramucosal (Tis) lesions, and rate of T1 or more deeply invasive cancers were 3.7% (66/1,764), 3.9% (32/820), and 3.6% (34/944), respectively. Thirty-three patients' MMRs were investigated; 7 (21%) exhibited deficient MMRs (dMMRs), comprising 4 with T2 or more deeply invasive cancers and 5 whose lesions were in the proximal colon. Twenty-three tumors' genomic mutations were investigated; PIK3CA had mutated in 5 of 6 T2 or more deeply invasive cancers, of which, 4 were located in the proximal colon. Two patients with dMMRs and BRAF mutations had poor prognoses. Sixty-one percent (17/28) of the macroscopic type 0 lesions were superficial. All superficial Tis and T1 PCCRCs were detected <24 months after the negative colonoscopies. They were distributed throughout the colon and rectum. DISCUSSION: PCCRCs may be invasive cancers in the proximal colon that exhibit dMMRs and/or PIK3CA mutations or missed early CRCs especially superficial lesions.

Clinical usefulness of the S-O clip during colorectal endoscopic submucosal dissection in difficult-to-access submucosal layer.

Background and study aims In colorectal endoscopic submucosal dissection (ESD), the S-O clip improves the accessibility to the submucosal layer of the colon. However, its safety and usefulness in difficult colorectal ESDs are unclear. Thus, in this study, we aimed to assess the effectiveness of the S-O clip in colorectal ESD in the difficult-to-access submucosal layer. Patients and methods From January 2016 to December 2016, 189 consecutive cases of colorectal ESD were performed at Hiroshima University Hospital before the S-O clip was introduced. Between January 2017 and June 2018, among 271 consecutive colorectal ESD cases, 41 cases were performed colorectal ESD using the S-O clip. We compared outcomes between the two groups (41 cases with S-O clip [use group] and 189 cases without S-O clip [non-use group]) using propensity score matching. Results Prior to propensity score matching, 41 cases with the S-O clip (use group) and 189 cases without the S-O clip (non-use group) were extracted. The degree of submucosal fibrosis was more severe and the procedure time was longer in the use group than in the non-use group. In the use and non-use groups, en bloc resection (100 % vs. 94.7 %) and complete en bloc resection (100 % vs. 92.6 %) rates were satisfactory. After propensity score matching, 33 cases in each group were extracted. As a result, complete en bloc resection rate was significantly higher in the use group than in the non-use group (100 % vs. 84.9 %). Conclusion The S-O clip is effective and can be used safely in colorectal ESD in the difficult-to-access submucosal layer.

Can surveillance colonoscopy be discontinued in an elderly population with diminutive polyps?

OBJECTIVES: Surveillance colonoscopy after endoscopic resection (ER) for adenomatous polyps reduces the incidence and mortality of colorectal cancer (CRC). However, its significance in the elderly population is uncertain. The study aimed to determine whether surveillance colonoscopy should be discontinued in the elderly population. METHODS: We enrolled 105 patients who underwent baseline colonoscopy between January 2004 and December 2009 and were subsequently followed-up over 5 years in our institution. All had diminutive colorectal polyps and were aged <80 years at baseline colonoscopy and ≥80 years at follow-up in May 2018. Patients who had undergone colectomy or who had inflammatory bowel disease, familial adenomatous polyposis, Lynch syndrome, and no diminutive polyps were excluded. The cumulative incidence of the target lesion was evaluated. Histopathological diagnoses included low-grade dysplasia (LGD), high-grade dysplasia (HGD), and carcinoma. RESULTS: The target lesion was detected in 15% (16/105) of the patients. There was no invasive carcinoma; however, two HGDs were detected. There were three lesions that had increased from previously detected diminutive lesions, all of which were LGDs. There were no target lesions detected after 84 years of age, and the cumulative incidence was 0.20. The cumulative incidence was significantly higher in the group with HGD than in the group with no target lesions at baseline colonoscopy. There was no HGD after age 79 years, and the cumulative incidence was 0.019. CONCLUSION: Surveillance colonoscopy for patients with diminutive polyps may be discontinued after age 79 years.

A case of primary malignant melanoma of the esophagus with a widely expanded surface area.

Primary malignant melanoma of the esophagus (PMME) is rare but aggressive. PMME accounts for approximately 0. 1% of all malignant esophageal neoplasms occurring worldwide, and is usually diagnosed during the advanced stage. A 67-year-old man underwent an esophagogastroduodenoscopy (EGD) at our hospital and confirmed 20 mm of black pigmentation in the lower esophagus in the chest area. Pathological biopsy findings of the black-pigmented epithelial tissue revealed the presence of tumor cells with brown granules, leading to the diagnosis of malignant melanoma. Owing to difficulty in accurately diagnosing the range in this PMME case, we performed thoracoscopic esophagectomy. Pathological organisation test results were pT1a-LPM, INFb, pN0, and pM0, which were diagnosed at pStage I. The lesion expanded extensively, measuring > 10 cm in diameter. The tumor cells, which were centrally located in the black-pigmented area, were observed to have proliferated beyond the surrounding brownish area into the mucosa, but no findings were found in the endoscopic examination. As in this case, because PMME may diffusely spread along the basal layer outside the range of pigmentation, endoscopic diagnosis of the extent of disease spread may be impossible; hence, it is important to keep this phenomenon in mind while performing resection to treat PMME.

Early-stage serrated adenocarcinomas are divided into several molecularly distinct subtypes.

Serrated adenocarcinoma (SAC) is considered the end stage of the serrated neoplasia pathway. Although SAC prognosis is not widely recognized, the serrated pathway-associated subtype consistently exhibits unfavorable prognosis in genetic studies. Herein, we classified molecularly distinct subtypes of serrated adenocarcinomas and clarified their associated clinicopathological characteristics and genetic changes. We examined 38 early-stage colorectal SACs. Of these, 24 were classified into three molecularly distinct groups by colon cancer subtyping (CCS). The clinicopathological characteristics, Ki 67 labeling index (LI), and SAC epithelial serration were assessed. The DNA from carcinomas and normal tissue/adenoma was extracted by laser microdissection and sequenced by next-generation sequencing, and mutation numbers and patterns of a 15-oncogene panel were determined. The CCS groups included CCS1 (CDX2+, HTR2B-, FRMD6-, ZEB1-, and microsatellite instable-low [MSI-L]/microsatellite stable [MSS]; 14 cases), CCS2 (microsatellite instable-high [MSI-H], 5 cases), and CCS3 (CDX2-, HTR2B+, FRMD6+, ZEB1+, and MSI-L/MSS; 5 cases). Invasive cancer was significantly more frequent in CCS3 than in CCS1 (5/5 versus 3/14, respectively). Ki67 LI and epithelial serration were higher in CCS3 than in CCS1 (83.0 ± 5.8 versus 65.4 ± 4.0 and 5/5 versus 3/14, respectively; p = 0.031 and 0.0048). CCS2 showed the highest mutation number, whereas KRAS and BRAF mutation numbers were higher in CCS3 than in CCS1. Early-stage SACs were classified into three molecularly distinct subtypes with different clinicopathological and genetic characteristics.

The utility of a novel colonoscope with retroflexion for colorectal endoscopic submucosal dissection.

Background and study aims The PCF-H290TI/L produced by Olympus is a novel colonoscope equipped with some advantageous features for endoscopic treatment. It is expected to improve the potential for retroflexion and overall endoscope operability, which can reduce the difficulty of performing colorectal ESD. The aim of this study was to evaluate the utility of the novel colonoscope in colorectal ESD. Methods Three hundred and forty-eight consecutive colorectal lesions resected via ESD between June 2014 and January 2017 at Hiroshima University Hospital were included in the retroflexion ability analysis. We compared the retroflexion potential of PCF-H290TI to that of a conventional endoscope. Two hundred and twenty-seven colorectal lesions located in the left-sided colon and resected with ESD between April 2009 and February 2018 were enrolled in the treatment outcome analysis. Treatment outcomes using PCF-H290TI compared to those of the conventional colonoscope, and outcomes of the PCF-H290TI with retroflexion compared to those of the conventional colonoscope without retroflexion were evaluated by propensity score matching. Results The retroflexion rate with the PCF-H290TI was 76 %, which was significantly higher than the 44 % rate with the conventional scope. Endoscope operability was better and dissection speed was faster when using the PCF-H290TI with retroflexion compared to the conventional colonoscope without retroflexion. There were no significant differences between the groups in en bloc resection rate and adverse events. Conclusion Compared to the conventional colonoscope, the PCF-H290TI/L made it easier to perform ESD via a retrograde approach regardless of tumor location, and thus may be useful for performing colorectal ESD.