Unified Magnifying Endoscopic Classification (UMEC) of Gastrointestinal Lesions: A North American Validation Study.

Background and study aim: Magnifying endoscopy enables the diagnosis of advanced neoplasia throughout the gastrointestinal tract. The unified magnifying endoscopic classification (UMEC) framework unifies optical diagnosis criteria in the esophagus, stomach, and colon, dividing lesions into three categories: non-neoplastic, intramucosal neoplasia, and deep submucosal invasive cancer. This study aims to ascertain the performance of North American endoscopists when using the UMEC. Methods: In this retrospective cohort study, five North American endoscopists without prior training in magnifying endoscopy independently diagnosed images of gastrointestinal tract lesions using UMEC. All endoscopists were blinded to endoscopic findings and histopathological diagnosis. Using histopathology as the gold standard, the endoscopists' diagnostic performances using UMEC were evaluated. Results: A total of 299 lesions (77 esophagus, 92 stomach, and 130 colon) were assessed. For esophageal squamous cell carcinoma, the sensitivity, specificity, and accuracy ranged from 65.2% (95%CI: 50.9-77.9) to 87.0% (95%CI: 75.3-94.6), 77.4% (95%CI: 60.9-89.6) to 96.8% (95%CI: 86.8-99.8), and 75.3% to 87.0%, respectively. For gastric adenocarcinoma, the sensitivity, specificity, and accuracy ranged from 94.9% (95%CI: 85.0-99.1) to 100%, 52.9% (95%CI: 39.4-66.2) to 92.2% (95%CI: 82.7-97.5), and 73.3% to 93.3%. For colorectal adenocarcinoma, the sensitivity, specificity, and accuracy ranged from 76.2% (95%CI: 62.0-87.3) to 83.3% (95%CI: 70.3-92.5), 89.7% (95%CI: 82.1-94.9) to 97.7% (95%CI: 93.1-99.6), and 86.8% to 90.7%. Intraclass correlation coefficients indicated good to excellent reliability. Conclusion: UMEC is a simple classification that may be used to introduce endoscopists to magnifying narrow-band imaging and optical diagnosis, yielding satisfactory diagnostic accuracy.

Establishment of Standards for the Referral of Large Non-Pedunculated Colorectal Polyps: An International Expert Consensus Using a Modified Delphi Process.

BACKGROUND AND AIMS: Resection of colorectal polyps has been shown to decrease the incidence and mortality of colorectal cancer. Large non-pedunculated colorectal polyps are often referred to expert centres for endoscopic resection, which requires relevant information to be conveyed to the therapeutic endoscopist to allow for triage and planning of resection technique. The primary objective of our study was to establish minimum expected standards for the referral of LNPCP for potential ER. METHODS: A Delphi methodology was employed to establish consensus on minimum expected standards for the referral of large colorectal polyps among a panel of international endoscopy experts. The expert panel was recruited through purposive sampling, and three rounds of surveys were conducted to achieve consensus, with quantitative and qualitative data analysed for each round. RESULTS: A total of 24 international experts from diverse continents participated in the Delphi study, resulting in consensus on 19 statements related to the referral of large colorectal polyps. The identified factors, including patient demographics, relevant medications, lesion factors, photodocumentation and the presence of a tattoo, were deemed important for conveying the necessary information to therapeutic endoscopists. The mean scores for the statements ranged from 7.04 to 9.29 out of 10, with high percentages of experts considering most statements as a very high priority. Subgroup analysis by continent revealed some variations in consensus rates among experts from different regions. CONCLUSION: The identified consensus statements can aid in improving the triage and planning of resection techniques for large colorectal polyps, ultimately contributing to the reduction of colorectal cancer incidence and mortality.

From Staining Techniques to Artificial Intelligence: A Review of Colorectal Polyps Characterization.

This review article provides a comprehensive overview of the evolving techniques in image-enhanced endoscopy (IEE) for the characterization of colorectal polyps, and the potential of artificial intelligence (AI) in revolutionizing the diagnostic accuracy of endoscopy. We discuss the historical use of dye-spray and virtual chromoendoscopy for the characterization of colorectal polyps, which are now being replaced with more advanced technologies. Specifically, we focus on the application of AI to create a "virtual biopsy" for the detection and characterization of colorectal polyps, with potential for replacing histopathological diagnosis. The incorporation of AI has the potential to provide an evolutionary learning system that aids in the diagnosis and management of patients with the best possible outcomes. A detailed analysis of the literature supporting AI-assisted diagnostic techniques for the detection and characterization of colorectal polyps, with a particular emphasis on AI's characterization mechanism, is provided. The benefits of AI over traditional IEE techniques, including the reduction in human error in diagnosis, and its potential to provide an accurate diagnosis with similar accuracy to the gold standard are presented. However, the need for large-scale testing of AI in clinical practice and the importance of integrating patient data into the diagnostic process are acknowledged. In conclusion, the constant evolution of IEE technology and the potential for AI to revolutionize the field of endoscopy in the future are presented.

Long-term efficacy of antireflux mucosectomy in patients with refractory gastroesophageal reflux disease.

OBJECTIVES: Minimally invasive treatments have been applied for gastroesophageal reflux disease (GERD), but the long-term results are controversial. Antireflux mucosectomy (ARMS) is a simple endoscopic procedure that does not require the insertion of a foreign body. We provide the first report on the long-term results of ARMS. METHODS: This was a single-center, single-arm trial, prospective study of 88 patients with proton pump inhibitor (PPI)-refractory GERD who underwent ARMS between June 2012 and June 2017. Primary outcomes were the rates of long-term effectiveness and PPI discontinuation. Secondary outcomes were to compare patients' preoperative background characteristics, questionnaire, and multichannel intraluminal impedance and pH monitoring data to examine the predictive factors of ARMS. The clinical course was reviewed, including the need for additional treatment after ARMS. RESULTS: Antireflux mucosectomy produced a long-term effect in 68.3% of the patients, and PPI could be discontinued in 42% of patients. There were significant differences in age, intensity of preoperative symptoms, and acid-related indicators. Forty-five percent (27/60) had reflux hypersensitivity and ARMS provided long-term effectiveness in 81% of these patients. There was no significant difference in subjective symptom assessment between those with short-term and long-term efficacy. Additional treatment was administered in 23% (14/60) and scheduled at 1-2 years' follow-up. CONCLUSIONS: Antireflux mucosectomy showed long-term efficacy, and many of the cases with short-term effects were able to maintain them. In addition, ARMS is also effective in patients with reflux hypersensitivity, and provides a treatment option that bridges the gap between surgical and medical treatment.

Endoscopic carbon dioxide insufflation tolerance test on the anal sphincter for anorectal hypofunction: a pilot and feasibility study.

Background: Anorectal function deteriorates with age. The diagnostic performance of the endoscopic pressure study integrated system (EPSIS), an endoscopic carbon dioxide (CO2) insufflation stress test of the lower esophageal sphincter has been previously evaluated as a diagnostic tool for gastroesophageal reflux disease. We aimed to evaluate the applicability of EPSIS in improving anorectal function. We hypothesized that EPSIS can be applied to the diagnosis of lower gastrointestinal tract disorders. Methods: This was a pilot, single-center, retrospective study using prospectively collected data between December 2021 and March 2022. It was designed to evaluate the differences in EPSIS rectal pressure measurements between older (≥80 years) and younger (<80 years) patients. At the end of the screening colonoscopy, the colonoscope was fixed in a retroflex position. When bowel movement was observed, CO2 was insufflated to the point where gas leakage occurred through the anus. The measured maximum pressure was defined as EPSIS-rectal pressure max (EPSIS-RP max) and compared between the groups. Results: Overall, 30 patients were included and examined. The median ages of the <80 and ≥80 years' groups were 53 (range: 27-79) and 82 (range: 80-94) years, respectively, with corresponding median measured EPSIS-RP max of 18.7 (range: 8.5-30.2) and 9.8 (range: 5.4-22.3) mmHg (P<0.001). Conclusions: Measurement of maximum rectal pressure illustrates the age-related decline in physiological anorectal function. Future studies should consider a loading test using EPSIS to quantify the decline in anorectal function and use it as a routine tool for screening and adjunctive diagnosis of anorectal hypofunction.

The third space for endoscopic treatment of motility disorders of the gastrointestinal tract.

Over the last few decades, we have seen the further advancement and progress of the field of interventional and therapeutic endoscopy, bringing us to undiscovered areas of the gut's lumen. The development of peroral endoscopic myotomy (POEM) created a breakthrough in the field of therapeutic endoscopy by bringing us to the so-called "third space," which is an artificially created space in the submucosal layer. The rise of third space endoscopy brought us novel and fundamental aspects into therapeutic endoscopy by paving the way to interventions throughout the gastrointestinal (GI) tract. With the success of POEM, the same third space principles have become the foundation for the development of other third space endoscopic techniques for the management of motility disorders of the GI tract, giving rise to a number of POEM offshoots. Since motility disorders of the GI tract are commonly encountered in clinical practice, the development of third space endoscopic interventions to address these disorders was seemingly timely, providing patients optimal care. In this chapter, we would like to offer a closer look and provide the readers a general overview of POEM and other POEM-based techniques which have been developed for the management of motility disorders of the GI tract.

Evolving field of third-space endoscopy: Derivatives of peroral endoscopic myotomy.

Third-space endoscopy, also known as submucosal endoscopy, allows for a wide range of therapeutic interventions within the submucosal layer and even into the muscular or subserosal layers of the gastrointestinal lumen. The technical development of peroral endoscopic myotomy (POEM) for achalasia has revolutionized the field of therapeutic endoscopy and the method has been continuously refined and modified. Although POEM has been applied to treat primary achalasia, it shows a favorable clinical response in other esophageal motility disorders and as a salvage treatment after previously failed intervention. Gastroesophageal reflux after POEM has drawn considerable attention and there have been major advancements in its prevention and management. POEM has led to advantageous derivatives such as peroral endoscopic tumor resection or submucosal tunneling endoscopic resection for resection of subepithelial lesions, Zenker POEM for hypopharyngeal diverticula, diverticular POEM for epiphrenic esophageal diverticula, and gastric POEM for refractory gastroparesis. These techniques have a similar concept, which constitutes submucosal tunneling with a mucosal flap valve and secure mucosal incision closure. The submucosal tunneling technique is widely accepted and continues to evolve. This study aimed to review in detail the indications, outcomes, and technical variations in POEM and explore several emerging submucosal tunneling procedures. This review will benefit future studies by providing a summary of recent developments in this field.

Learning curve for peroral endoscopic myotomy in therapeutic endoscopy experts and nonexperts: Large single-center experience.

OBJECTIVES: Reports on learning curve for peroral endoscopic myotomy (POEM) in therapeutic endoscopy nonexperts are limited. We aimed to assess the number of cases required to achieve POEM proficiency for endoscopic submucosal dissection (ESD) experts and nonexperts. METHODS: This is a retrospective study at the largest POEM referral center in Japan. POEM between April 2014 and December 2020 were included. Nonexperts and ESD experts were divided by training phases: A, 1-20; B, 21-40; C, 41-60; D, 61-80; and E, 81-100 cases. Primary outcome was operation time, and the phase to reach target time (83 min) was investigated. Secondary outcomes were clinical success rate, adverse events, and post-POEM gastroesophageal reflux disease (GERD). RESULTS: Five hundred and sixty-six cases were performed by 14 nonexperts, and 555 cases by 15 ESD experts. As the primary outcome, operation time in nonexperts was: A, 95 (79-115.8); B, 86.5 (71-105); C, 80 (70-100); D, 73 (64.5-100.5); and E, 73.5 (57.8-88.8) min, while in ESD experts: A, 90 (74-128); B, 77 (70-92); and C, 77 (70-93.5) min (median [interquartile range]). Operation time decreased significantly as experience increased in both groups (P < 0.001), and nonexperts required 41-60 cases to achieve proficiency, while experts required 21-40 cases. As secondary outcomes, in nonexperts, clinical success was 96.9-100%, adverse events were 5.0-9.2%, symptomatic GERD was 11.8-26.5%, and proton pump inhibitor (PPI) intake was 11.5-18.7% in each phase. While in experts, clinical success was 96.2-100%, adverse events were 3.0-5.8%, symptomatic GERD was 14.6-22.0%, and PPI intake was 12.6-17.9%. There were no significant differences among training phases. CONCLUSIONS: Non-ESD experts require more cases to achieve proficiency in POEM. These results are useful for establishing POEM training programs and institutional implementation of the procedure.

Association between endoscopic pressure study integrated system (EPSIS) and high-resolution manometry.

Background and study aims The endoscopic pressure study integrated system (EPSIS), a novel diagnostic tool for gastroesophageal reflux disease (GERD), allows evaluation of the anti-reflux barrier using endoscopy by monitoring the intragastric pressure (IGP) during insufflation. In this study, we evaluated the association between EPSIS results and lower esophageal sphincter (LES) function measured by high-resolution manometry (HRM) to elucidate whether EPSIS can evaluate the LES function. Patients and methods A retrospective, single-center study of patients with GERD symptoms who underwent endoscopy, pH-impedance monitoring, EPSIS, and HRM was conducted. The primary outcome was basal LES pressure and the secondary outcomes were end-respiratory LES pressure and integrated relaxation pressure (IRP). As EPSIS parameters, the following were measured: 1) pressure difference (mmHg), the difference between maximum and basal IGP; and 2) pressure gradient (mmHg/s), calculated by dividing pressure difference by the insufflating time. Pressure difference < 4.7 mmHg or pressure gradient < 0.07 mmHg/s was defined as an EPSIS GERD pattern. Results Forty-seven patients (median age: 53 years, 37 female) were analyzed. Pressure difference and pressure gradient significantly correlated with basal LES pressure (ρ = 0.29; P =  0.04 and ρ = 0.29; P =  0.04). Patients with EPSIS GERD pattern showed significantly lower basal LES pressure [13.2 (4.8-26.6) vs 25.3 (10.4-66.7) mmHg, P =  0.002], lower end-respiratory LES pressure [8.5 (1.1-15.9) vs 15.5 (1.9-43.9) mmHg, P =  0.019] and lower IRP [5.9 (1.0-12.0) vs 9.8 (1.3-17.8) mmHg, P =  0.020]. Conclusions This study showed a close association between EPSIS results and LES pressures measured by HRM. This indicates that EPSIS can evaluate the LES function during endoscopy and endorse the role of EPSIS as a diagnostic tool for GERD.

Successful endoscopic full-thickness resection of an exophytic subepithelial lesion with double scope traction technique.

Video 1Video demonstrating the endoscopic full-thickness resection of an exophytic subepithelial lesion with "double scope traction" technique.

Per-oral endoscopic myotomy as treatment for Killian-Jamieson diverticulum.

Killian-Jamieson diverticulum (KJD) is a rare type of esophageal diverticulum less commonly encountered compared with Zenker's diverticulum (ZD). Endoscopic approach for these diverticula has been rapidly evolving. Currently, a flexible endoscopic septum division is considered the first-line treatment for symptomatic ZD patients, however reported recurrence rates are over 10% according to recent literature. With the advent of submucosal tunneling technique established by per-oral endoscopic myotomy for achalasia, it has been applied to treat ZD named as Zenker's diverticulum per-oral endoscopic myotomy (Z-POEM) as a minimally invasive treatment. Although there are very few reports utilizing submucosal tunneling approach to KJD, we have opted to perform Z-POEM in order to safely perform complete dissection of the muscle septum while maintaining mucosal integration. Due to the difficulty of anatomical location of KJD, we created mucosal incision and subsequent submucosal tunnel directly at the level of the septum as opposed to creating a submucosal tunnel few centimeters proximal to the septum as being previously proposed. We report a case in which this technique was successfully performed with complete resolution of dysphagia without any adverse event. This technique permits to perform complete myotomies without the fear of causing perforation. Although larger cohorts are required to assess its safety and efficacy, Z-POEM to treat KJD seems to be promising.

Comparison of scope holding sign on endoscopy and lower esophageal sphincter contraction on high-resolution manometry: A pilot study.

Objectives: Lower esophageal sphincter (LES) plays a key role in gastroesophageal reflux disease (GERD) pathogenesis. In retroflexion and under sufficient insufflation, it can be seen how the lower esophagus grasps the endoscope, which we named scope holding sign (SHS). This study aimed to compare the SHS and LES pressure on high-resolution manometry (HRM), to elucidate whether the sphincter can be visualized endoscopically. Methods: This was a single-center, prospective pilot study. Patients with symptoms of GERD, who underwent endoscopy and HRM between February 2021 and April 2021, were included. A manometry catheter and an ultra-slim endoscope were inserted, and the resting LES pressure was measured. The lower esophagus holding (SHS-positive) and releasing (SHS-negative) the endoscope and catheter were observed. The LES pressures during SHS-positive and SHS-negative were compared. Results: Eleven patients (median age: 57 years; eight men) with normal esophageal motility were analyzed. The median LES pressure in SHS-positive was significantly higher than the resting LES pressure (40.4 [22.9-74.0] vs. 25.9 [2.0-66.7] mm Hg; p = 0.001) and the LES pressure in SHS-negative (4.6 [1.5-9.3]; p = 0.001). Furthermore, the LES pressure in SHS-negative was significantly lower than the resting LES pressure (4.6 [1.5-9.3] vs. 25.9 [2.0-66.7] mm Hg; p = 0.005). Conclusions: This study demonstrated that the SHS parallels LES pressure, indicating that the sphincter can be observed endoscopically. This may enable us to evaluate LES function during endoscopy in patients with GERD, thus, deserving further evaluation in future studies.

Treatment of achalasia with peroral endoscopic myotomy in situs inversus totalis.

Peroral endoscopic myotomy (POEM) has become established as a safe, effective, and versatile minimally invasive endoscopic treatment for achalasia and other esophageal motility disorders. Situs inversus totalis is a rare congenital disorder characterized by a completely reversed position (mirror-image) of the thoracic and abdominal visceral organs. This case report demonstrated a successful treatment of achalasia in a situs inversus totalis by POEM. Similar to the POEM procedure in a normal patient, it is important to maintain the orientation throughout the submucosal tunneling while keeping in mind the reversed orientation and anatomical landmarks. The submucosal tunnel and myotomy were created by an anterior approach which is in this case located at the reversed axis, at 10 o'clock position. There were no major technical modifications needed to be carried out by the operator. No adverse events were noted. Improvement in the Eckardt Symptom Score as well as the barium esophagogram and high-resolution manometry findings on 2-month follow-up exhibited that although POEM was performed in a reversed orientation, similar effects and outcomes were achieved, indicating a successful procedure in this case. In summary, by keeping in mind the reversed positioning and anatomical landmarks in situs inversus totalis, POEM shows to be a safe, effective, and versatile intervention in treating achalasia in situs inversus totalis without the need for major modifications in the procedural technique.

Achalasia with esophageal intramural hematoma treated by per-oral endoscopic myotomy (POEM).

Esophageal intramural hematoma (EIH) is a condition which occurs as a result of hemorrhage within the esophageal wall including the submucosal layer. However, reports of EIH on achalasia patients are quite limited and per-oral endoscopic myotomy (POEM) for achalasia with EIH has not been reported. This is the first case report that demonstrated a successful treatment of achalasia with EIH by POEM. In achalasia, since there is absence of lower esophageal sphincter relaxation, as barotraumatic pathogenesis, an increase in the intraesophageal pressure may cause EIH. As direct traumatic pathogenesis, the stasis of food may directly injure the esophageal wall resulting in EIH. After confirming the hematoma healed until it became an ulcer, POEM was performed on the posterior axis since the intramural hematoma was located anteriorly. The procedure was completed successfully without any occurrence of adverse events. On 2-months follow-up, improvement in dysphagia was noted, and complete epithelialization of the intramural hematoma region was seen on endoscopic examination. On 1-year follow-up, patient did not have recurrence of dysphagia and intramural hematoma. In summary, we reported a case of achalasia with EIH, which was treated by POEM. POEM procedure may be effective not only for the improvement of dysphagia but also for a better ulcer healing and prevention of intramural hematoma recurrence.

Novel modified side-by-side balloon dilatation method for esophagogastric junction strictures: Single-/double-barrel techniques.

Endoscopic balloon dilatation is an established treatment for benign gastrointestinal strictures. In order to dilatate safely, it is necessary to dilatate gradually and preferably under direct endoscopic visualization. However, it is currently difficult to achieve dilatation widths of 20-30 mm with commercial products and of over 30-mm with endoscopic visualization. Therefore, a safe and innovative application technique is needed for patients who need these 20-mm or greater dilatation widths. We have developed two methods that enable more than 20-mm dilatation under direct visualization. (i) Single-barrel method: an endoscopic balloon dilatation catheter was fixed with grasping forceps at the tip of the endoscope and carried into the stomach. The balloon catheter was released from the endoscope to create a retroflexed view. The endoscope and balloon were positioned adjacent to each other at the gastric cardia. The balloon was inflated gradually and the esophagogastric junction was dilatated under direct visualization. (ii) Double-barrel method: the same procedure was repeated with two balloons. Theoretically, we achieved a dilatation of >30-mm in diameter. These modified methods may be helpful for esophagogastric junction strictures, such as esophageal achalasia (serving as an initial endoscopic balloon dilatation prior to using a 30-mm achalasia balloon), or for functional strictures after Nissen fundoplication. In conclusion, our simple, modified method enables safe and gradual dilatation under direct endoscopic visualization. Additionally, combination of the sizes of one or two balloons can achieve various widths of dilatation.

Geriatric patients with esophageal motility disorders benefit more from minimally invasive peroral endoscopic myotomy: a multicenter study in Japan.

Geriatric patients with existing studies on the safety and efficacy of peroral endoscopic myotomy (POEM) for achalasia involve small sample sizes and single institutions. However, multi-center, large-scale data analyses are lacking. The study aimed to clarify the characteristics of geriatric patients with esophageal motility disorders (EMDs) and determine the procedure-related outcomes and clinical course following POEM. This cohort study included 2,735 patients with EMDs who were treated at seven Japanese facilities between 2010 and 2019. The patients' characteristics and post-POEM clinical courses were compared between the geriatric (age ≥ 75 years; n = 321) and non-geriatric (age < 75 years; n = 2,414) groups. Compared with the non-geriatric group, the geriatric group had higher American Society of Anesthesiologists physical status scores; more recurrent cases; lower incidence of chest pain; and higher incidence of type III achalasia, distal esophageal spasm, and Jackhammer esophagus. Furthermore, the incidence of sigmoid esophagus was higher, although esophageal dilation was not severe in this group. POEM was safe and effective for geriatric patients with treatment-naïve and recurrent EMDs. Furthermore, compared with the non-geriatric group, the geriatric group had lower post-POEM Eckardt scores, fewer complaints of refractory chest pain, and a lower incidence rate of post-POEM reflux esophagitis. Geriatric patients are characterized by worse clinical conditions, more spastic disorders, and greater disease progression of EMDs, which are also the indications for minimally invasive POEM. POEM is more beneficial in geriatric patients as it has lowering symptom scores and incidence rates of reflux esophagitis.

Unified magnifying endoscopic classification for esophageal, gastric and colonic lesions: a feasibility pilot study.

Background and study aims Image-enhanced magnifying endoscopy allows optimization of the detection and diagnosis of lesions found in the gastrointestinal tract. Current organ-specific classifications are well-accepted by specialized endoscopists but may pose confusion for general gastroenterologists. To address this, our group proposed the Unified Magnifying Endoscopic Classification (UMEC) which can be applied either in esophagus, stomach, or colon. The aim of this study was to evaluate the diagnostic performance and clinical applicability of UMEC. Patients and methods A single-center, feasibility pilot study was conducted. Two endoscopists with experience in magnifying narrow band imaging (NBI), blinded to white-light and non-magnifying NBI findings as well as histopathological diagnosis, independently reviewed and diagnosed all images based on UMEC. In brief, UMEC is divided into three categories: non-neoplasia, intramucosal neoplasia, and deep submucosal invasive cancer. The diagnostic performance of UMEC was assessed while using the gold standard histopathology as a reference. Results A total of 303 gastrointestinal lesions (88 esophageal squamous lesions, 90 gastric lesions, 125 colonic lesions) were assessed. The overall accuracy for both endoscopists in the diagnosis of esophageal squamous cell cancer, gastric cancer, and colorectal cancer were 84.7 %, 89.5 %, and 83.2 %, respectively. The interobserver agreement for each organ, Kappa statistics of 0.51, 0.73, and 0.63, was good. Conclusions UMEC appears to be a simple and practically acceptable classification, particularly to general gastroenterologists, due to its good diagnostic accuracy, and deserves further evaluation in future studies.

Endoscopic Classifications of Early Gastric Cancer: A Literature Review.

Endoscopic technologies have been continuously advancing throughout the years to facilitate improvement in the detection and diagnosis of gastric lesions. With the development of different endoscopic diagnostic modalities for EGC, several classifications have been advocated for the evaluation of gastric lesions, aiming for an early detection and diagnosis. Sufficient knowledge on the appearance of EGC on white light endoscopy is fundamental for early detection and management. On the other hand, those superficial EGC with subtle morphological changes that are challenging to be detected with white light endoscopy may now be clearly defined by means of image-enhanced endoscopy (IEE). By combining magnifying endoscopy and IEE, irregularities in the surface structures can be evaluated and highlighted, leading to improvements in EGC diagnostic accuracy. The main scope of this review article is to offer a closer look at the different classifications of EGC based on several endoscopic diagnostic modalities, as well as to introduce readers to newer and novel classifications, specifically developed for the stomach, for the assessment and diagnosis of gastric lesions.