Partial Stent-in-Stent Method with an Uncovered Self-Expandable Metallic Stent for Unresectable Malignant Hilar Bile Duct Obstruction.

(1) Background: There is controversy regarding stent placement for unresectable malignant hilar biliary obstruction (UMHBO). We mainly use the partial stent-in-stent (PSIS) method with an uncovered self-expandable metallic stent (UCSEMS) based on the drainage area and patency period. In this study, we investigated the usefulness and safety of the PSIS method. (2) Methods: In total, 59 patients who underwent the PSIS method for UMHBO at our hospital were included in the study. The technical success rate, clinical success rate, time to recurrent biliary obstruction (TRBO) and overall survival (OS) from the first placement, factors affecting TRBO and OS, and early complications within 30 days after the procedure were evaluated retrospectively. (3) Results: The technical and clinical success rates were 100% and 96.6%, respectively, with a TRBO of 121 days [95% confidence interval: 82-231] and an OS of 194 days [95% confidence interval: 113-305] after the first placement. Early complications occurred in nine patients (15.3%), including five cases of cholangitis, three cases of pancreatitis, and one case of cholecystitis. (4) Conclusions: The PSIS method for UMHBO is safe and useful with high technical and clinical success rates.

Safety and Diagnostic Yield of Endoscopic Ultrasound-Guided Fine-Needle Biopsy for Hypervascular Pancreatic Lesions.

Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is a common technique for diagnosing pancreatic lesions with high accuracy and a low incidence of procedural adverse events. However, occasional adverse events, particularly bleeding, may occur. Procedures for hypervascular lesions are considered important, but their risks are unknown. We aimed to evaluate the safety and diagnostic yield of EUS-FNB for hypervascular pancreatic solid lesions. This study included 301 patients with 308 solid pancreatic lesions who underwent EUS-FNB between May 2011 and December 2018. We performed propensity-score matching to balance clinical differences between hypervascular and hypovascular lesions and analyzed 52 lesions. We compared the safety and diagnostic performance of propensity score-matched cohorts. The sensitivity, specificity, and accuracy rates of EUS-FNB for hypervascular lesions were 94.7%, 100%, and 96.2%, and those for hypovascular lesions were 80.0%, 100%, and 84.6%, respectively. There was no difference in diagnostic performance between hypervascular and hypovascular lesions. Furthermore, adverse events occurred in only one patient (pancreatitis) in the hypovascular group. There were no significant differences in the occurrence of adverse events between hypervascular and hypovascular lesions (0% vs. 3.8%, p = 1.000). Therefore, EUS-FNB may be safe with a high diagnostic yield, even for hypervascular solid pancreatic lesions.

Pancreatic Juice Cytology Evaluations Using Synthetic Secretin and Serial Pancreatic Juice Aspiration Cytological Examination for the Diagnosis of Pancreatic Ductal Adenocarcinoma.

Pathological examination by endoscopic ultrasound-fine needle aspiration is not possible in approximately 10% of pancreatic tumor cases. Pancreatic juice cytology (PJC) is considered an alternative diagnostic method. However, its diagnostic capability is insufficient, and PJC has been repeatedly redevised. Serial pancreatic juice aspiration cytological examination (SPACE) and secretin-loaded PJC (S-PJC) have been recently introduced as alternative diagnostic methods. This study aimed to determine the diagnostic capacity and safety of SPACE and S-PJC using a propensity score-matched analysis. The sensitivity, specificity, and accuracy were 75.0%, 100%, and 92.3% for S-PJC, respectively, and 71.4%, 100%, and 92.3% for SPACE, respectively, meaning that there was no significant difference between the groups. Four patients (15.4%) each in the S-PJC and SPACE groups experienced complications, including postendoscopic retrograde cholangiopancreatography, pancreatitis, and cholangitis. Overall, there was no difference in efficacy and safety between the SPACE and S-PJC groups.

Comparison between Target Sample Check Illuminator and White Light Observation in Discriminating the Presence of Target Specimen for Endoscopic Ultrasound-Guided Fine Needle Aspiration Sample.

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is an essential endoscopic tissue sampling method for diagnosing pancreatobiliary diseases; however, determining the presence of target specimens mixed in the blood by conventional observation is challenging due to the small size of the obtained sample. This study investigated the usefulness of a target sample check illuminator (TSCI) that emits a specific wavelength of light to determine the presence of target specimens. Twenty-seven patients who underwent EUS-FNA at our hospital were included. Conventional white light observation was performed for the collected samples, followed by TSCI; six people evaluated the presence of the target specimen on a 5-point scale. The target specimen discrimination score using TSCI (median: 5) was significantly higher than that using conventional white light observation (median: 1) (p < 0.001). No significant difference was observed in the discrimination score between the evaluator (novice vs. expert, p = 0.162) and puncture needle (22G vs. 25G, p = 0.196). The discriminability of TSCI in the samples obtained using EUS-FNA was significantly higher than that of conventional observation. TSCI does not depend on the evaluator or puncture needle for the identification of the target specimen; hence, it can provide a good pathological specimen and may contribute to the improvement of the diagnostic ability.

The Usefulness of Peroral Cholangioscopy for Intrahepatic Stones.

Peroral cholangioscopy (POCS) is believed to be effective in treating intrahepatic stones; however, reports on its efficacy are few. We reviewed the results of intrahepatic stones treated with fluoroscopic guidance or POCS. This study included 26 patients who underwent endoscopic treatment for intrahepatic stones at our institution between January 2017 and December 2021. We retrospectively evaluated the procedure time and adverse events in the first session and the rate of complete stone removal. Complete stone removal was achieved in 92% (24/26); POCS was required in 16 of 26 (62%) procedures and the complete stone removal was achieved in 15 of 16 (94%) of these procedures. The POCS group had a significantly longer procedure time than the fluoroscopy group. Cholangitis incidence was high; however, no difference was noted between patients with and without POCS, and all cases were mild and treated conservatively. Endoscopic treatment for intrahepatic stones may lead to an increase in the incidence of cholangitis, requires specialized devices such as a cholangioscope, and should be performed in an established institution by experienced staff. POCS is useful for intrahepatic stones formed upstream of the stenosis and intrahepatic stones piled in the bile duct.

Modified BEST-J Score Model Predicts Bleeding after Endoscopic Submucosal Dissection with Fewer Factors.

This study constructed a simplified post-endoscopic submucosal dissection (ESD) prediction model with a prognostic nutritional index (PNI). A total of 449 patients who underwent gastric ESD was included, divided with a ratio of 2:1, and assigned to the model or validation cohort. A prediction model of post-ESD (modified BEST-J score) was constructed using the model cohort. The modified BEST-J score was evaluated by comparing its accuracy to the BEST-J score in the validation cohort. Within 4 weeks of ESD, melena, hematemesis, or a 2 g/dL or greater decrease in hemoglobin level that required esophagogastroduodenoscopy was defined as post-ESD bleeding. In the model cohort, 299 patients were enrolled and 25 (8.4%) had post-ESD bleeding. Independent risk factors for post-ESD bleeding were use of P2Y12RA, tumor size > 30 mm, location of lesion at lower one-third of the stomach, and PNI ≤ 47.9. Constructing the modified BEST-J score based on these variables, the sensitivity, specificity, and positive likelihood ratio were 73.9%, 78.1%, and 3.37. When comparing the modified BEST-J score to the BEST-J score in the validation cohort, no significant difference was observed by ROC-AUC (0.77 vs. 0.75, p = 0.81). Modified BEST-J score can predict post-ESD bleeding more simply, with the same accuracy as the BEST-J score.

Intracellular glutathione levels affect the outcomes of verteporfin-mediated photodynamic therapy in esophageal cancer cells.

Photodynamic therapy (PDT) induces cancer cell death by generating reactive oxygen species (ROS). In this process, photosensitizers accumulate in cancer cells irradiated by laser light of a specific wavelength, leading to ROS generation. Verteporfin (VP), a second-generation photosensitizer, is used in PDT for age-related macular degeneration. However, the antitumor effects of VP-PDT remain poorly defined. This study investigated the antitumor effects of VP-PDT on esophageal cancer (EC) cell lines in vitro. Two types of EC cell lines, the KYSE30 cell line, derived from highly differentiated esophageal carcinoma, and the KYSE170 cell line, derived from moderately differentiated carcinoma, were used in this study. VP-PDT exerted effective anticancer effects in both cell lines. Our results revealed that the low-density lipoprotein receptor, albumin receptor, and heme carrier protein-1 in VP uptake were not involved in VP uptake. However, cells rich in intracellular glutathione were resistant to VP-PDT. Our study outcomes suggest that lowering intracellular glutathione via a glutathione synthesis inhibitor or sulfasalazine can increase the effectiveness of VP-PDT-mediated anticancer effects.

Review on acute pancreatitis attributed to COVID-19 infection.

The coronavirus disease 2019 (COVID-19) is known to cause gastrointestinal symptoms. Recent studies have revealed COVID-19-attributed acute pancreatitis (AP). However, clinical characteristics of COVID-19-attributed AP remain unclear. We performed a narrative review to elucidate relation between COVID-19 and AP using the PubMed database. Some basic and pathological reports revealed expression of angiotensin-converting enzyme 2 and transmembrane protease serine 2, key proteins that aid in the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the pancreas. The experimental and pathological evaluation suggested that SARS-CoV-2 infects human endocrine and exocrine pancreas cells, and thus, SARS-CoV-2 may have a direct involvement in pancreatic disorders. Additionally, systemic inflammation, especially in children, may cause AP. Levels of immune mediators associated with AP, including interleukin (IL)-1ß, IL-10, interferon-γ, monocyte chemotactic protein 1, and tumor necrosis factor-α are higher in the plasma of patients with COVID-19, that suggests an indirect involvement of the pancreas. In real-world settings, some clinical features of AP complicate COVID-19, such as a high complication rate of pancreatic necrosis, severe AP, and high mortality. However, clinical features of COVID-19-attributed AP remain uncertain due to insufficient research on etiologies of AP. Therefore, high-quality clinical studies and case reports that specify methods for differential diagnoses of other etiologies of AP are needed.

Efficacy and Safety of Pancreatic Juice Cytology with Synthetic Secretin in Diagnosing Malignant Intraductal Papillary Mucinous Neoplasms of the Pancreas.

The risk of malignant transformation of intraductal papillary mucinous neoplasm (IPMN) is presently assessed using imaging, which remains unsatisfactory. Given the high viscosity of pancreatic juice, pancreatic juice cytology (PJC) is considered an investigational procedure. We previously demonstrated that the diagnostic performance of PJC was improved via synthetic secretin loading in pancreatic ductal carcinoma. This study aimed to evaluate the efficacy of synthetic secretin-loaded PJC (S-PJC) for IPMN. The usefulness and safety of S-PJC were prospectively evaluated in 133 patients with IPMN. Overall, 92, 12, and 26 patients had branch duct, main duct, and mixed-type lesions, respectively. The risk classifications based on the 2017 international consensus guidelines were high-risk stigmata, worrisome features, and no risk in 29, 59, and 45 patients, respectively. Synthetic secretin loading improved the sensitivity of PJC from 50.0% to 70.8%. Complications included 13 (9.8%) cases of mild pancreatitis, 1 (0.8%) case of acute cholangitis, and 1 (0.8%) case of Mallory-Weiss syndrome, all of which resolved with conservative treatment. In conclusion, synthetic secretin-loaded PJC improved the diagnostic performance of cytology for malignant IPMN. We recommend using synthetic secretin-loaded PJC for the preoperative pathological diagnosis of malignant IPMN in clinical settings.

Large Gallstones Stacked Together in the Common Bile Duct after Choledochojejunostomy.

A 65-year-old man had a history of cholecystectomy and treatment for cholelithiasis with a common bile duct incision. Owing to frequent cholangitis, he underwent choledochojejunostomy. Twenty years after the surgery, he was hospitalized for cholangitis and was suspected of having hilar cholangiocarcinoma based on imaging findings. Percutaneous transhepatic cholangioscopy using a SpyGlass™ DS (Boston Scientific, Marlborough, USA) showed gallstones and bile sludge in the bile ducts, but no tumors were noted. Electrohydraulic shockwave lithotripsy with double-balloon enteroscopy enabled complete stone removal; a direct visual biopsy with peroral cholangioscopy showed no malignancy in the bile duct.

Peroral Cholangioscopy-Guided Forceps Mapping Biopsy for Evaluation of the Lateral Extension of Biliary Tract Cancer.

BACKGROUND: Peroral cholangioscopy (POCS)-guided forceps mapping biopsy (FMB) is a method for the accurate preoperative identification of the extent of the disease of biliary tract cancer (BTC). However, the diagnostic value of POCS-FMB is still uncertain. OBJECTIVES: We evaluated the diagnostic utility of POCS-FMB for the identification of lateral extension-superficial intraductal spread longitudinally and continuously from the main lesion-of BTC. METHODS: In the retrospective study, patients who received POCS-FMB and surgery for curative resection of BTC between September 2016 and August 2019 at our medical institution were enrolled. The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was evaluated. Furthermore, we also evaluated the factors affecting the diagnostic accuracy of POCS-FMB. RESULTS: A total of 23 patients with BTC were enrolled, and 24 procedures of POCS-FMB from 96 sites of biliary tracts were performed. The sensitivity, specificity, and accuracy of POCS-FMB were 53.8%, 63.9%, and 63.1%, respectively. In the multivariate logistic regression analyses, the biopsy from the bifurcation of biliary tracts was a significant factor affecting the diagnostic accuracy of POCS-FMB (odds ratio 3.538, 95%; confidence interval 1.151-10.875, p = 0.027). CONCLUSIONS: The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was insufficient. The biopsy from the bifurcation of biliary tracts was a positive factor affecting the diagnostic accuracy of POCS-FMB.

Peroral cholangioscopy-guided forceps biopsy versus fluoroscopy-guided forceps biopsy for extrahepatic biliary lesions.

BACKGROUND AND AIM: Endoscopic retrograde cholangiopancreatography (ERCP)-related tissue acquisition, including fluoroscopy-guided forceps biopsy (F-FB), is a common technique in diagnosing indeterminate biliary lesions. Recently, peroral cholangioscopy (POCS) and POCS-guided forceps biopsy (POCS-FB) has also been used for the diagnosis of indeterminate biliary lesions. However, it is uncertain which of those techniques were superior for the diagnosis of extrahepatic cholangiocarcinoma (ECC). We aimed to evaluate the diagnostic yield and safety of F-FB for indeterminate biliary lesions compared with POCS-FB. METHODS: Patients who underwent F-FB or POCS-FB to evaluate indeterminate biliary lesions between October 2011 and August 2019 were enrolled retrospectively. We carried out propensity score matching to balance these clinical differences between the F-FB group and POCS-FB group. In the propensity score-matched cohort, we compared the diagnostic performance of F-FB with that of POCS-FB based on the pathological evaluation. We also evaluate adverse events associated with F-FB and POCS-FB. RESULTS: We enrolled 113 patients with biliary diseases, and 62 patients were analyzed in the propensity score-matched cohort. Sensitivity, specificity, and accuracy of F-FB were 82.4, 100, and 90.3%, and for POCS-FB, those values were 83.3, 100, and 90.3%, respectively. There were no significant differences in the diagnostic performance between F-FB and POCS-FB. There were also no significant differences in the occurrence of adverse events between F-FB and POCS-FB (41.9 vs 29.0%, P = 0.289). CONCLUSIONS: The diagnostic yield of F-FB for ECC is similar to that of POCS-FB. POCS-FB is not necessary for the initial pathological diagnosis of indeterminate biliary lesions.

Adequate tissue acquisition rate of peroral cholangioscopy-guided forceps biopsy.

BACKGROUND: Peroral cholangioscopy (POCS)-guided forceps biopsy is a method for diagnosing indeterminate biliary strictures and for the preoperative identification of the exact perihilar and distal margins of biliary tract cancer (BTC). However, POCS-guided forceps biopsy may result in an insufficient amount of specimen at times. Therefore, we evaluated the adequate tissue acquisition rate and the factors affecting the adequate tissue acquisition of POCS-guided forceps biopsy for the biliary tract. METHODS: Patients who underwent POCS-guided forceps biopsy for biliary disease between September 2016 and October 2018 at our hospital were enrolled retrospectively. We evaluated the adequate tissue acquisition rate of POCS-guided forceps biopsy for the biliary lesion and that for non-stenotic bile duct. In addition, the factors affecting the adequate tissue acquisition rate of POCS-guided forceps biopsy were evaluated. RESULTS: We enrolled 47 patients with biliary disease and performed POCS-guided forceps biopsy for biliary lesion and POCS-guided forceps mapping biopsy for non-stenotic bile duct in 40 and 36 patients, respectively. The adequate tissue acquisition rates of POCS-guided forceps biopsy for biliary lesions and that for non-stenotic bile duct were 86.4%, and 68.9%, respectively. In the multivariate logistic regression analyses, age, and previous biliary stenting before POCS were factors affecting the adequate tissue acquisition rate of POCS-guided forceps biopsy for the biliary lesion. For non-stenotic bile duct, the location of the biliary lesion, endoscopic sphincterotomy (EST), and procedure time of POCS were factors affecting the adequate tissue acquisition rate of POCS-guided forceps mapping biopsy. CONCLUSIONS: Previous biliary stenting was a factor affecting a low tissue acquisition rate of POCS-guided forceps biopsy for the biliary lesion. In the POCS-guided forceps mapping biopsy, the location of the biliary lesion, EST, and procedure time were factors affecting tissue acquisition rates.

A Case of Right Hepatic Artery Syndrome Diagnosed by Using SpyGlassDSTM System.

We report the case of a 68-year-old woman who had abdominal pain and slightly elevated biliary enzymes. Magnetic resonance cholangiopancreatography detected biliary duct stenosis, while contrast-enhanced magnetic resonance imaging showed that the right hepatic artery transversed the extrahepatic bile duct at the level of bifurcation of the bile duct. We performed endoscopic retrograde cholangiopancreatography and peroral cholangioscopy with the SpyGlass DS™ system. Then, mild extrinsic pulsatile compression of the bile duct was observed at stricture level with an intact bile duct epithelium. Therefore, she was diagnosed with right hepatic artery syndrome and underwent cholecystectomy. Six months later, her biliary enzyme level decreased, and the recurrence of pain gradually decreased.

Programmed cell death-1 inhibitor-related sclerosing cholangitis: A systematic review.

BACKGROUND: Programmed cell death-1 (PD-1) inhibitor has been indicated for many types of malignancies. However, these inhibitors also cause immune-related adverse events. Hepatobiliary disorder is a phenotype of immune-related adverse event affecting 0%-4.5% of patients treated with PD-1 inhibitors. Recent studies have reported PD-1 inhibitor-related sclerosing cholangitis (SC); however, the associated clinical and pathological features are unclear. AIM: To evaluate the clinical and pathological features of PD-1 inhibitor-related SC through a systematic review of the literature. METHODS: The review, conducted using electronic databases in PubMed, was restricted to the period from January 2014 to September 2019 and focused on case reports/series on PD-1 inhibitor-related SC published in English. We scanned the references of the selected literature to identify any further relevant studies. Six cases previously studied by us, including three that have not yet been published, were included in this review. RESULTS: Thirty-one PD-1 inhibitor-related SC cases were evaluated. Median age of patients was 67 years (range, 43-89), with a male to female ratio of 21:10. The main disease requiring PD-1 inhibitor treatment was non-small cell lung cancer. Agents that caused PD-1 inhibitor-related SC were nivolumab (19 cases), pembrolizumab (10 cases), avelumab (1 case), and durvalumab (1 case). The median number of cycles until PD-1 inhibitor-related SC onset was 5.5 (range, 1-27). Abdominal pain or discomfort (35.5%, 11/31) was the most frequent symptom. Blood serum tests identified liver dysfunction with a notable increase in biliary tract enzymes relative to hepatic enzymes, and a normal level of serum immunoglobulin G4. Biliary dilation without obstruction (76.9%, 20/26), diffuse hypertrophy of the extrahepatic biliary tract (90.5%, 19/21), and multiple strictures of the intrahepatic biliary tract (30.4%, 7/23) were noted. In 11/23 (47.8%) cases, pathological examination indicated that CD8+ T cells were the dominant inflammatory cells in the bile duct or peribiliary tract. Although corticosteroids were mainly used for PD inhibitor-related SC treatment, the response rate was 11.5% (3/26). CONCLUSION: Some clinical and pathological features of PD-1 inhibitor-related SC were revealed. To establish diagnostic criteria for PD-1 inhibitor-related SC, more cases need to be evaluated.

A Simple Method for Measuring Adenosine Triphosphate in Acute Cholangitis Patients to Determine the Need for Emergency Biliary Drainage.

Objective Acute cholangitis is occasionally life-threatening and requires immediate treatment. For the management of acute cases, globally accepted diagnostic criteria and the use of severity grading, as defined in the Tokyo Guidelines 2018 (TG18), are recommended. This study was performed to explore the association between acute cholangitis and the level of adenosine 5'-triphosphate (ATP) in blood as determined with a simple measurement method. Methods Twenty-three consecutive patients admitted for acute cholangitis and 14 healthy individuals were enrolled. Based on the TG18, the patients were categorized according to the degree of severity as Grade I, II, or III. We measured the amount of ATP in blood samples using a bioluminescence meter and evaluated the correlation with the degree of severity. Results The ATP/total hemoglobin (tHgb) level showed a significant decline in association with an increase in severity, as that in the healthy controls was 236.60 ± 8.10 and in the Grade I, II, and III groups was 238.56 ± 6.98, 186.88 ± 7.62, and 154.60 ± 11.01, respectively (p<0.01). While no significant difference was observed between the healthy controls and Grade I patients (p=0.649), there was a statistically significant difference between Grade I and Grade II (p<0.01) in the ATP/tHgb level. According to a receiver operating characteristic analysis, the area under the curve for ATP/tHgb, used as an index for predicting the need for emergency biliary drainage (Grade II, III cases), was the highest among various examined factors. Conclusion The present novel measurement method was found to be simple to perform and useful for detecting acute cholangitis patients with a low ATP level who may require emergency biliary drainage.

Measurement of Adenosine Deaminase in Ascitic Fluid Contributed to the Diagnosis in a Case of Tuberculous Peritonitis.

A diagnosis of tuberculous peritonitis (TBP) is difficult because of nonspecific manifestation and limited effectiveness of conventional diagnostic tools. Recently, the usability of measurement of ascitic adenosine deaminase (ADA) was shown. We report here a case of TBP in which measurement of ascitic ADA contributed to the diagnosis. A 93-year-old male developed a large amount of ascites. Analyses of the ascitic fluid revealed exudation, though antibiotics treatment was ineffective. Using paracentesis, the ADA level in the ascites was measured and shown to be high. Under suspicion of TBP, an exploratory laparoscopy was performed and a definitive diagnosis of TBP was made.

Peroral Cholangioscopy-Guided Forceps Biopsy and Endoscopic Scraper for the Diagnosis of Indeterminate Extrahepatic Biliary Stricture.

BACKGROUND: Peroral cholangioscopy (POCS) has become a widely-used technique in diagnosing indeterminate biliary strictures, enabling optical viewing of the biliary system and targeted biopsies under direct vision. The diagnostic utility of the new endoscopic scraper, Trefle®, for extrahepatic cholangiocarcinoma (ECC) has also been reported. However, the diagnostic utility of POCS-guided and Trefle®-assisted tissue acquisition for ECC has never been compared empirically. We evaluated the efficacy and safety of Trefle®-assisted tissue acquisition for diagnosing ECC compared with POCS-guided tissue sampling. METHODS: Patients who underwent Trefle®-assisted tissue acquisition or POCS-guided forceps biopsy to differentiate ECC from benign biliary disease between April 2014 and March 2018 were enrolled retrospectively. We evaluated the diagnostic performance of Trefle®-assisted tissue acquisition and POCS-guided forceps biopsy based on pathological evaluation. We also compared adverse events associated with Trefle®-assisted tissue acquisition with those of POCS-guided forceps biopsy. RESULTS: We enrolled 34 patients with biliary disease and performed Trefle®-assisted tissue acquisition and POCS-guided forceps biopsy in 14 and 20 patients, respectively. Sensitivity, specificity, and accuracy of Trefle®-assisted tissue acquisition were 87.5%, 83.3%, and 85.7%, respectively, and for POCS-guided forceps biopsy, these were 90.0% each. Statistical values of Trefle®-assisted tissue acquisition and POCS-guided tissue acquisition were not significantly different. There were no significant differences in the occurrence of adverse events between the Trefle®-assisted tissue acquisition and the POCS-guided forceps biopsy (35.7% vs. 25.0%, p = 0.770). Compared with patients who underwent POCS procedure, endoscopic sphincterotomy was performed for fewer patients who underwent Trefle®-assisted tissue acquisition (p < 0.001). CONCLUSIONS: The diagnostic ability of Trefle®-assisted tissue acquisition for ECC is similar to that of POCS-guided tissue acquisition. Trefle®-assisted tissue acquisition might also help to preserve the sphincter of Oddi and its digestive function.