A novel predictive formula for highly accurate discrimination between truly Helicobacter pylori-uninfected and currently infected/spontaneously eradicated individuals for gastric cancer screening.

The ABC classification, which categorizes gastric cancer risk based on serum Helicobacter pylori (H pylori) antibody and pepsinogen levels, has a limitation of potentially misclassifying high-risk individuals as low risk. To overcome the problem, we previously developed a 4-parameter predictive formula (age, serum H pylori antibody, PGI, and PGII) using logistic regression analysis to accurately identify low-risk truly H pylori-uninfected status. Our predictive formula demonstrated superior sensitivity and specificity in distinguishing between low-risk truly uninfected individuals and high-risk currently/spontaneously eradicated status individuals, compared to the modified ABC classification based on latex immunoassay kits (traditional 3-parameter model). This study aimed to revalidate the diagnostic accuracy of the predictive formula in a new and different study population. We applied the predictive formula to the target population and compared the sensitivity and specificity with those of the traditional 3-parameter model. A total of 788 enrollees were analyzed: 703 were classified as truly uninfected, 45 as currently infected, and 40 as spontaneously eradicated according to the results of stool antigen testing and endoscopic findings. The sensitivities and specificities of the predictive formula and the traditional 3-parameter model were 89.5% and 87.1% versus 89.8% and 80.0%, respectively. The specificity of the predictive formula was superior in the 70 to 89 age range and H pylori antibody < 3 U/mL groups. The predictive formula had higher specificity than the traditional 3-parameter model. The results should contribute to efficient gastric cancer screening by predicting H pylori infection status.

Association of colonic metaplasia of goblet cells and endoscopic phenotypes of the J pouch in patients with ulcerative colitis: a retrospective pilot study.

BACKGROUND/AIMS: Mucosal adaptation of the ileum toward colonic epithelium has been reported in pouchitis in ulcerative colitis (UC); however, the clinical characteristics, endoscopic findings, and outcomes in patients with pouchitis with ileal mucosal adaptation are poorly understood. METHODS: This was a single-center retrospective study comprising UC patients treated by proctocolectomy with ileal pouch-anal anastomosis who had undergone pouchoscopy at the University of Tsukuba Hospital between 2005 and 2022. Endoscopic phenotypes were evaluated according to the Chicago classification. High-iron diamine staining (HID) was performed to identify sulfomucin (colon-type mucin)-producing goblet cells (GCs) in pouch biopsies. We compared clinical data between patients with (high HID group) and without > 10% sulfomucin-producing GCs in at least one biopsy (low HID group). RESULTS: We reviewed 390 endoscopic examination reports from 50 patients. Focal inflammation was the most common phenotype (78%). Five patients (10%) required diverting ileostomy. Diffuse inflammation and fistula were significant risk factors for diverting ileostomy. The median proportion of sulfomucin-producing GCs on histological analysis of 82 pouch biopsies from 23 patients was 9.9% (range, 0%-93%). The duration of disease was significantly greater in the high HID group compared to the low HID group. The median percentage of sulfomucin-producing GCs was significantly higher in patients with diffuse inflammation or fistula compared to other endoscopic phenotypes (14% vs. 6.0%, P= 0.011). CONCLUSIONS: Greater proportions of sulfomucin-producing GCs were observed in endoscopic phenotypes associated with poor outcomes in UC, indicating patients with pouchitis showing colonic metaplasia of GCs may benefit from early interventions.

Clinical Usefulness of Hypoxia Imaging Colonoscopy for the Objective Measurement of Ulcerative Colitis Disease Activity.

BACKGROUND AND AIMS: Colonic mucosal hypoxia is associated with mucosal inflammation in ulcerative colitis (UC). We aimed to assess the clinical usefulness of hypoxia imaging colonoscopy for the assessment of clinical, endoscopic, and histologic disease activities of UC. METHODS: This was a retrospective cohort study comprised of 100 consecutive UC patients who underwent hypoxia imaging colonoscopy between September 2022 and September 2023 at the University of Tsukuba Hospital. We measured colonic tissue oxygen saturation (StO2) at the biopsy sites and compared StO2 values between different disease activities. We used receiver operating characteristic (ROC) analysis to calculate the area under the ROC curve (AUROC). RESULTS: We identified a significant correlation between rectal StO2 and the Simple Clinical Colitis Activity Index, with moderate accuracy to predict bowel urgency at a 40.5% cutoff (AUROC 0.74, 95% CI 0.62-0.87). Our analysis of 490 images showed median StO2 values for Mayo endoscopic subscores (MES) 0, 1, 2, and 3 as 52% (IQR 48%-56%), 47% (IQR 43%-52%), 42% (IQR 38.8%-47%), and 39.5% (IQR 37.3%-41.8%), respectively. Differences for all pairs were significant. Median StO2 was 49% (IQR 44%-54%) for Geboes scores 0-2, significantly higher than histologically active disease (Geboes score ≥ 3). At a colonic StO2 cutoff of 45.5%, AUROCs for endoscopically and histologically active diseases were 0.79 (95% CI 0.74-0.84) and 0.72 (95% CI 0.66-0.77), respectively. CONCLUSIONS: StO2 obtained by hypoxia imaging colonoscopy is useful for assessing clinical, endoscopic, and histologic activities of UC, suggesting StO2 may be a novel and objective endoscopic measurement.

First report from the International Evaluation of Endoscopic classification Japan NBI Expert Team: International multicenter web trial.

OBJECTIVES: Narrow-band imaging (NBI) contributes to real-time optical diagnosis and classification of colorectal lesions. The Japan NBI Expert Team (JNET) was introduced in 2011. The aim of this study was to explore the diagnostic accuracy of JNET when applied by European and Japanese endoscopists not familiar with this classification. METHODS: This study was conducted by 36 European Society of Gastrointestinal Endoscopy (ESGE) and 49 Japan Gastroenterological Endoscopy Society (JGES) non-JNET endoscopists using still images of 150 lesions. For each lesion, nonmagnified white-light, nonmagnified NBI, and magnified NBI images were presented. In the magnified NBI, the evaluation area was designated by region of interest (ROI). The endoscopists scored histological prediction for each lesion. RESULTS: In ESGE members, the sensitivity, specificity, and accuracy were respectively 73.3%, 94.7%, and 93.0% for JNET Type 1; 53.0%, 64.9%, and 62.1% for Type 2A; 43.9%, 67.7%, and 55.1% for Type 2B; and 38.1%, 93.7%, and 85.1% for Type 3. When Type 2B and 3 were considered as one category of cancer, the sensitivity, specificity, and accuracy for differentiating high-grade dysplasia and cancer from the others were 59.9%, 72.5%, and 63.8%, respectively. These trends were the same for JGES endoscopists. CONCLUSION: The diagnostic accuracy of the JNET classification was similar between ESGE and JGES and considered to be sufficient for JNET Type 1. On the other hand, the accuracy for Types 2 and 3 is not sufficient; however, JNET 2B lesions should be resected en bloc due to the risk of cancers and JNET 3 can be treated by surgery due to its high specificity.

Factors associated with increased duration of endoscopic submucosal dissection for rectal tumors: a 22-year retrospective analysis.

BACKGROUND AND AIMS: Colorectal endoscopic submucosal dissection (ESD) is widely used in several countries. However, it is associated with technical difficulties. Rectal ESD is considered an intermediate step in colorectal ESD training. Nevertheless, some rectal lesions require a longer procedure time than usual, and the reason for the prolonged time taken for these specific lesions remains unclear. Therefore, this study aimed to clarify the factors associated with prolonged rectal ESD. METHODS: In total, 483 rectal lesions resected using ESD from February 1998 to June 2021 were investigated. Prolonged ESD procedure time was defined as the time from the first submucosal injection to lesion removal exceeding 120 minutes, whereas other procedures were defined as average ESD procedure time. Clinicopathologic and endoscopic findings were compared between the 2 groups using univariate and multivariate analyses. RESULTS: One hundred forty-four lesions were resected using a prolonged ESD procedure time of 202.9 ± 92.3 minutes, whereas 339 lesions were resected using an average ESD procedure time of 77.8 ± 29.4 minutes. Multivariate analysis revealed that tumors involving the dentate line (P = .026), resection size ≥50 mm (P < .001), invasion depth ≥T1b (P = .006), and circumferential range ≥2/3 (P = .001) were independent risk factors for prolonged-duration ESDs, regardless of whether the procedure was performed by an expert or not. CONCLUSIONS: The results of the present study suggest that the location of a lesion involving the dentate line, resection size ≥50 mm, circumferential range ≥2/3, and invasion depth ≥T1b are the independent risk factors for prolonged ESD procedure time.

Video-based e-learning program for schoolteachers to support children of parents with mental illness: a cluster randomized trial.

BACKGROUND: Some children of parents with mental illness need support. This study aimed to develop and test the effectiveness of an e-learning program for training elementary schoolteachers to support children of parents with mental illness. METHODS: The program, which included a 30-min video-based e-learning program, aimed to help schoolteachers gain basic knowledge about mental illness and children of parents with mental illness, recognize children in need of support, and gain confidence in supporting them. A school-based cluster randomized controlled trial was conducted, and the schools were randomly divided into intervention and control groups. The teachers at these schools signed up for the program and participated individually. The outcome measures for the schoolteachers were evaluated at three time points: baseline (T1), post (T2), and one month later (T3). Along with the Sense of Coping Difficulty subscale (primary outcome measure), the following self-developed outcome measures were used: actual behaviors and attitude toward supporting children, knowledge, and self-assessment of program goals achievement. The Sense of Coping Difficulty subscale results at T3 were compared between the groups. Effectiveness over time was assessed for all the outcome measures. The interaction between baseline and intervention effects on the Sense of Coping Difficulty subscale was analyzed. As a part of the process evaluation, open-ended text responses were analyzed qualitatively. RESULTS: Baseline responses were collected from 87 participants in the intervention group and 84 in the control group. The total score of the Sense of Coping Difficulty subscale at T3 was significantly lower in the intervention group than in the control group (p = 0.007). Over time, a significant effect was observed on the Sense of Coping Difficulty subscale, actual behavior, knowledge of onset timing and probability of onset, and achievement of all program goals. Exploratory analysis was particularly effective for those who encountered a high level of difficulty in supporting children. The participants' text responses indicated that they planned to look carefully at children's backgrounds and stay close to them in the future. CONCLUSIONS: The program was effective for schoolteachers in supporting children of parents with mental illness. TRIAL REGISTRATION: UMIN000045483; 14/09/2021.

Childhood Adversities and Psychological Health of Adult Children of Parents with Mental Illness in Japan.

In this study, we seek to clarify whether the present-day experience of psychological distress among adults whose parents suffered from mental illness is related to their childhood experiences of abuse and neglect and their provision of emotional care for their parents during their school-age years. To this end, a web-based cross-sectional study was conducted. A total of 120 participants over the age of 20 who attended a self-help group responded (50% response rate); of these, 94 had a parent diagnosed with a mental illness, and these participants were included for data analysis purposes. Of the 94 respondents, 65 (69.2%) were highly distressed, as measured by a Kessler (K) 6 measure of ≥5. A logistic regression analysis revealed that the experience of providing emotional care for parents during school-age childhood was significantly related to high levels of distress in adulthood (OR = 3.48; 95% CI 1.21-9.96). For children of parents with mental illnesses, the effects of providing emotional care for parents during childhood may include long-term psychological distress. For this reason, mentally ill parents raising children need visiting community nurses or other professionals to provide emotional care on behalf of their children.

The Feasibility, Safety, and Long-term Outcomes of Endoscopic Submucosal Dissection for Colorectal Neoplasia in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Evidence regarding the utility of endoscopic submucosal dissection (ESD) for neoplasia in patients with inflammatory bowel disease (IBD) is limited. This meta-analysis aims to understand the feasibility, safety, and long-term outcomes of ESD in IBD patients. METHODS: Electronic databases were searched for observational and case-controlled studies. Primary endpoints were en bloc resection and margin-negative resection of neoplastic lesions. Secondary endpoints included procedure-related bleeding and perforation, local recurrence, and metachronous neoplasia. RESULTS: We analyzed 25 studies with a total of 585 neoplastic lesions in 552 patients. The rates of en bloc resection and margin-negative resection were 0.88 [95% confidence interval (CI) 0.82-0.92] and 0.78 (95% CI 0.72-0.83), respectively. Meta-regression analysis showed longer disease duration was significantly associated with the higher rate of en bloc resection. The rates of procedure-related bleeding and perforation were 0.080 (95% CI 0.057-0.11) and 0.055 (95% CI 0.038-0.081), respectively. The rates of local recurrence and metachronous neoplasia were 0.008 events/person-year (95% CI 0.002-0.013) and 0.031 event/person-year (95% CI 0.016-0.046), respectively. Meta-analysis of case-controlled studies found no significant differences in the endpoints between IBD patients treated by ESD and those treated by endoscopic mucosal resection, or non-IBD patients treated by ESD. CONCLUSIONS: ESD is a feasible and safe procedure to remove neoplastic lesions in IBD patients. Given there is a considerable risk of metachronous neoplasia development, postoperative surveillance colonoscopy with an appropriate consultation with surgeons is essential to monitor not only local recurrence but also neoplastic changes in the remaining colon.

Detection of colorectal adenomas with texture and color enhancement imaging: Multicenter observational study.

OBJECTIVES: We aimed to evaluate the efficacy of texture and color enhancement imaging (TXI), which allows the acquisition of brighter images with enhanced color and surface structure in colorectal polyp detection compared to white light imaging. METHODS: Patients who underwent colonoscopy with repeated ascending colon observation using TXI and white light imaging between August 2020 and January 2021 were identified in three institutions. The outcomes included the mean number of adenomas detected per procedure (MAP), adenoma detection rate (ADR), and ascending colonic adenoma miss rate (Ac-AMR). Logistic regression was used to determine the effects of the variables on the outcomes. RESULTS: We included 1043 lesions from 470 patients in the analysis. The MAP, ADR, flat polyp detection rate, and Ac-AMR in TXI and white light imaging were 1.5% (95% confidence interval 1.3-1.6%) vs. 1.0% (0.9-1.1%), 58.2% (51.7-64.6%) vs. 46.8% (40.2-53.4%), 66.2% (59.8-72.2%) vs. 49.8% (43.2-56.4%), and 17.9% (12.1-25.2%) vs. 28.2% (20.0-37.6%), respectively. TXI, age, withdrawal time, and endoscopy type were identified as significant factors affecting the MAP and the ADR using multivariate regression analysis. CONCLUSIONS: Our study indicates that TXI improve the detection of colorectal neoplastic lesions. However, prospective randomized trials are required to confirm these findings.

Unexpected adhesive bowel obstruction after endoscopic submucosal dissection of early sigmoid colon cancer.

Various complications of colorectal endoscopic submucosal dissection (ESD) have been reported, including bleeding, penetration, perforation, and coagulation syndrome. However, the occurrence of bowel obstruction after ESD is rare. We report a case of adhesive bowel obstruction after ESD for a laterally spreading tumor in the sigmoid colon. The 35-mm tumor was successfully removed by ESD without intraoperative complications. The patient had a fever, lower abdominal pain, and a small amount of bloody stool the day after ESD. Endoscopy revealed minor bleeding from the ESD scar, which was treated by hemostatic clips. Pathological analysis showed adenocarcinoma was exposed to the vertical margin; therefore, the resection was non-curative. At 39 days after ESD and 36 days after discharge, the patient had abdominal pain and nausea. She was readmitted with a diagnosis of adhesive bowel obstruction. Conservative treatment was ineffective; therefore, she underwent sigmoidectomy combined with partial resection of the small intestine because of small intestinal stenosis caused by inflammation. The pathological examination showed localized peritonitis around the sigmoid colon where ESD was performed. There was more fibrosis along the serous surface of the small intestine than on the sigmoid colon. We concluded that there was a micro-perforation that could not be detected by endoscopy or physical examination. This case indicates that adhesive bowel obstruction may occur as a complication of ESD.

Robust automated prediction of the revised Vienna Classification in colonoscopy using deep learning: development and initial external validation.

BACKGROUND: Improved optical diagnostic technology is needed that can be used by also outside expert centers. Hence, we developed an artificial intelligence (AI) system that automatically and robustly predicts the pathological diagnosis based on the revised Vienna Classification using standard colonoscopy images. METHODS: We prepared deep learning algorithms and colonoscopy images containing pathologically proven lesions (56,872 images, 6775 lesions). Four classifications were adopted: revised Vienna Classification category 1, 3, and 4/5 and normal images. The best algorithm-ResNet152-in the independent internal validation (14,048 images, 1718 lesions) was used for external validation (255 images, 128 lesions) based on neoplastic and non-neoplastic classification. Diagnostic performance of endoscopists was compared using a computer-assisted interpreting test. RESULTS: In the internal validation, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for adenoma (category 3) of 84.6% (95% CI 83.5-85.6%), 99.7% (99.5-99.8%), 90.8% (89.9-91.7%), 89.2% (88.5-99.0%), and 89.8% (89.3-90.4%), respectively. In the external validation, ResNet152's sensitivity, specificity, PPV, NPV, and accuracy for neoplastic lesions were 88.3% (82.6-94.1%), 90.3% (83.0-97.7%), 94.6% (90.5-98.8%), 80.0% (70.6-89.4%), and 89.0% (84.5-93.6%), respectively. This diagnostic performance was superior to that of expert endoscopists. Area under the receiver-operating characteristic curve was 0.903 (0.860-0.946). CONCLUSIONS: The developed AI system can help non-expert endoscopists make differential diagnoses of colorectal neoplasia on par with expert endoscopists during colonoscopy. (229/250 words).

Utility of red dichromatic imaging for identifying the bleeding point in endoscopic hemostasis of colonic diverticular bleeding.

Video 1Endoscopic hemostasis of colonic diverticular bleeding using red dichromatic imaging to identify the bleeding point.

Conditional inference tree models to perceive depth of invasion in T1 colorectal cancer.

BACKGROUND AND AIM: Accurate diagnosis of invasion depth for T1 colorectal cancer is of critical importance as it decides optimal resection technique. Few reports have previously covered the effects of endoscopic morphology on depth assessment. We developed and validated a novel diagnostic algorithm that accurately predicts the depth of early colorectal cancer. METHODS: We examined large pathological and endoscopic databases compiled between Jan 2015 and Dec 2018. Training and validation data cohorts were derived and real-world diagnostic performance of two conditional interference tree algorithms (Models 1 and 2) was evaluated against that of the Japan NBI-Expert Team (JNET) classification used by both expert and non-expert endoscopists. RESULTS: Model 1 had higher sensitivity in deep submucosal invasion than that of JNET alone in both training (45.1% vs. 28.6%, p < 0.01) and validation sets (52.3% vs. 40.0%, p < 0.01). Model 2 demonstrated higher sensitivity than Model 1 (66.2% vs. 52.3%, p < 0.01) in excluding deeper invasion of suspected Tis/T1a lesions. CONCLUSION: We discovered that machine-learning classifiers, including JNET and macroscopic features, provide the best non-invasive screen to exclude deeper invasion for suspected Tis/T1 lesions. Adding this algorithm improves depth diagnosis of T1 colorectal lesions for both expert and non-expert endoscopists.

The Optimal Cut-off of the Latex Immunoassay (LZ Test) for Helicobacter pylori Infection Based on the Stool Antigen Test and Helicobacter pylori-associated Gastritis.

Objective Helicobacter pylori antibody kits using the latex immunoassay (LIA) are widely used in Japan. However, the optimal cut-off of the LIA remains unclear. This study clarified the optimal cut-off of the LIA for assessing the current infection status of patients (currently infected, never infected, spontaneously eradicated) in clinical practice. Methods In total, 482 subjects with no history of H. pylori eradication therapy who underwent a medical examination at our hospital were enrolled. The infection status was ascertained using a stool antigen test, and the endoscopic findings of H. pylori-associated gastritis. H. pylori antibody levels were measured using the LIA. Results In total, 414, 38, and 30 subjects were categorized into the never-infected, currently infected, and spontaneously eradicated groups. The optimal cut-off based on receiver operating characteristic curve analysis was 4 U/mL, whereas the area under the curve, sensitivity, and specificity for differentiating never-infected and currently infected subjects were 0.95, 92.1%, and 94.7%, respectively. When applying the cut-off of 4 U/mL to the judgment of current infection in all subjects, the sensitivity and specificity were 92.1% and 92.6%, respectively. Conclusion Our findings suggest that 4 U/mL was the optimal cut-off for differentiating current infection from no prior infection, and the value may be stable because of the exclusion of subjects with spontaneous eradication. The cut-off may be useful in initial screening for current H. pylori infection.

Anal Intraepithelial Neoplasia: Precursor of Anal Squamous Cell Carcinoma.

Anal squamous cell carcinoma (SCC) is rare, but it has been commonly detected as an invasive cancer. The standard treatment for anal SCC was surgical resection. However, recent medical advances have enabled the standard treatment to be chemoradiotherapy. Anal intraepithelial neoplasia (AIN) is a premalignant lesion of SCC. The screening test for AIN and human papilloma virus vaccine are important for the following high-risk patients: patients positive for human immunodeficiency virus and men who have sexual intercourse with men. Although cytology can be easily applied for a screening test, the false-negative rate for AIN is high. Instead, high-resolution anoscopy (HRA) has been gaining attention as a promising screening method for high-risk patients. Investigations comparing characteristic findings of HRA with the histology of AIN have demonstrated that HRA is a highly specific test for AIN. Magnifying or image-enhanced endoscopies are also routinely used for colonoscopy, as they allow detailed observations at higher magnifications than those of HRA. Hence, these endoscopic modalities can be applied for assessing AIN. Ablation therapies or topical medications are available as the local treatment for AIN. Although endoscopic submucosal dissection is considered to be feasible to remove AIN, it has a technical difficulty to approach endoscopically invisible areas. Hence, this technique may be useful to resect AIN localized in the endoscopically visible areas, when the localization is confirmed via targeted biopsy.

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.

Endoscopic features of colorectal lymphoma according to histological type.

Background and Aim: This study aimed to investigate the relationship between the histological type of colorectal lymphoma and its endoscopic features. Methods: We retrospectively analyzed patients with primary colorectal lymphoma who were diagnosed using colonoscopy and biopsy specimens at the National Cancer Center Hospital, Tokyo, Japan. The lesions were macroscopically classified into the following types via colonoscopy: polypoid, ulcerative, multiple lymphomatous polyposis, diffuse, and mixed. Results: A total of 117 lesions were identified in 90 patients enrolled in this study. Of these, 59 (50%) were located in the ileocecal region, 23 (20%) in the rectum, 9 (8%) in the transverse colon, 8 (7%) in the sigmoid colon, 7 (6%) in the descending colon, and 4 (3%) in the ascending colon. Moreover, the most common histological subtypes were diffuse large B-cell lymphoma (DLBCL) in 39 patients (43%) and mantle cell lymphoma (MCL) in 23 patients (26%), followed by follicular lymphoma (FL; 17%), mucosa-associated lymphoid tissue (MALT) lymphoma (9%), peripheral T-cell lymphoma-NOS (2%), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL; 2%), and Burkitt lymphoma (1%). More than half of the DLBCL (52%), MCL (52%), and MALT (56%) lymphomas were macroscopically classified as polypoid types. In contrast, FL lesions showed various macroscopic types. The majority of DLBCL (62%) and FL (78%) lesions were distributed in the ileocecal region. MCL lesions tended to be widely spread in various sites of the large intestine. Conclusions: Colorectal lymphomas showed macroscopically distinctive features depending on the histological type. Understanding the macroscopic classification of the lesions by colonoscopy and its distribution may be helpful in diagnosing the type of lymphoma and determining the malignant grade based on the histological types.