Current Situation and Problems in Diagnosis of Early Chronic Pancreatitis.

OBJECTIVES: The Japan Pancreas Society introduced the concept of early chronic pancreatitis (ECP) in 2009, but its epidemiology remains unclear. This study investigated challenges in ECP diagnosis. METHODS: Early chronic pancreatitis was diagnosed in 4 cohorts between April 2019 and November 2021 using the Clinical Diagnostic Criteria for Chronic Pancreatitis 2019. These cohorts included patients with abdominal/back pain, abnormal pancreatic enzyme levels, ECP suspected due to other reasons, and those who underwent endoscopic ultrasonography for other diseases. RESULTS: A total of 2502 cases were analyzed and 150 (40 alcoholic and 110 nonalcoholic) cases with ECP findings on endoscopic ultrasonography were included. Early chronic pancreatitis was confirmed in 14 cases (9%), including 9 (22.5%) alcoholic and 5 (4.5%) nonalcoholic cases. Early chronic pancreatitis was confirmed in 15%, 0%, 2.2%, and 0.13% cases in the 4 cohorts, respectively. Early chronic pancreatitis was confirmed in 10 (48%) of the 21 (14%) cases with pancreatic pain. CONCLUSIONS: Early chronic pancreatitis diagnostic rate was low, particularly in nonalcoholic cases, but was slightly higher in cases with pancreatic pain. The diagnostic rate was highest in the abdominal/back pain group. Further studies are required to establish appropriate diagnostic criteria for ECP.

A case of groove pancreatitis with duodenal stenosis successfully treated by endoscopic ultrasonography-guided pancreaticogastrostomy.

One of the reasons for groove pancreatitis is caused by the leakage of pancreatic juice into the space between the pancreatic head, descending duodenum, and common bile duct. Endoscopic drainage of Santorini's duct (SD) via the minor papilla is reportedly efficacious but can be difficult due to duodenal stenosis. We report Santorini's duct drainage using endoscopic ultrasonography-guided pancreaticogastrostomy (EUS-PGS) for a case of groove pancreatitis with gastric outlet obstruction. Gastric outlet obstruction was improved after 7 months of EUS-PGS with internal drainage through the Santorini's duct/minor papilla. EUS-PGS may be effective for treating groove pancreatitis with duodenal stenosis. This is the first report of groove pancreatitis with duodenal stenosis, the symptoms of which were improved by EUS-PGS.

Measurement of the anchoring force of covered self-expandable and lumen-apposing metal stents for interventional endoscopic ultrasonography.

OBJECTIVES: Interventional endoscopic ultrasonography is performed for various situations that require drainage, after which stent migration is the most severe adverse event. Several lumen-apposing metal stents (LAMS) and covered self-expandable metal stents (CSEMS) provide antimigration systems; however, their anchoring ability has not been studied well. Therefore, we measured and compared the anchoring force (ACF) of commercially available LAMS and CSEMS. METHODS: Anchoring force was measured for five types of LAMS (NAGI, SPAXUS, Plumber, and AXIOS 8 and 10 mm) and seven types of CSEMS (BCL, SHCL, BCG, BPD [four types of HANAROSTENT], HILZO, Niti-S [Spring Stopper], and Wallflex). We created a phantom model for inducing stent migration. It has a rotatable part as a curved fixture, and we measured ACF at angles between 0° and 40°. RESULTS: The mean ACF at 0° and 20° were NAGI 1.50, 1.84 N, SPAXUS 1.73, 1.72 N, Plumber 2.64, 2.03 N, and AXIOS 3.96, 3.61 N, respectively; and BCL 0.48, 0.53 N, Wallflex 0.53, 0.48 N, SHCL 0.64, 0.73 N, HILZO 1.09, 1.09 N, BCG 1.22, 1.20 N, BPD 1.78, 1.67 N, and Spring Stopper 2.29, 2.51 N. CONCLUSION: We measured ACF in LAMS and CSEMS with a new phantom model. The highest value among the LAMS was for the AXIOS and among the CSEMS was for the Spring Stopper. Some of the ACF values varied with the direction of pull. These findings may have a significant impact on stent selection for interventional endoscopic ultrasonography, and this model can be used to evaluate newly developed stents.

Retrospective evaluation of slim fully covered self-expandable metallic stent for unresectable malignant hilar biliary obstruction.

BACKGROUND: There have been few reports of covered self-expandable metallic stent (SEMS) placement for malignant hilar-biliary obstruction (MHBO) because of risk of biliary branch obstruction. We studied feasibility and efficacy of 6-mm-diameter, slim, fully covered SEMS (SFCSEMS) in a relatively large cohort. METHODS: We retrospectively evaluated SFCSEMS in unresectable MHBO from December 2016 to September 2021 in Juntendo University Hospital. RESULTS: We enrolled consecutive 54 unresectable MHBO (18 bile duct, 11 gallbladder, eight pancreatic, two hepatocellular, and 15 metastatic cancer cases) including Bismuth-type II (n = 11), III (n = 17), and IV (n = 26), and placed two (n = 35) or three (n = 19) SFCSEMS. The technical and clinical success rate was 100% and 92.5%, respectively, with 76.3 min of mean procedure time. Recurrent biliary obstruction (RBO) was observed in 35.2% and the median cumulative time to RBO (TRBO) was 181 days. Other adverse events were 11.1% (four mild-pancreatitis, one segmental-cholangitis, and one cholecystitis). There were no failed cases of stent exchange and second SFCSEMS (n = 6) showed significantly lower RBO (16.7% vs. 81.8%, P = .0364) and longer TRBO (undefined vs 86 days; P = .0617) than plastic stent (n = 11). CONCLUSIONS: Endoscopic placement of SFCSEMS for unresectable MHBO was effective and feasible with low incidence of segmental cholangitis, and exchange strategy of SFCSEMS was promising.

Endoscopic Ultrasound-guided Hepaticogastrostomy in a Seven-year-old Girl.

Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is an effective biliary drainage procedure in adult cases with difficult biliary access. However, there have been no reports on this procedure being used in pediatric cases. We successfully performed EUS-HGS in a pediatric case with a surgically altered anatomy. A standard convex-type echoendoscope and standard devices were used, and there were no device-related complications. The benefit of EUS-HGS for pediatric patients was avoidance of a percutaneous tube, which is difficult to maintain in active children. The accumulation of further cases and performance of a prospective study are warranted to standardize and expand the experience with this procedure.

Pancreatic Adenocarcinoma With Strong Expression of Interleukin-13 Receptor α2 Shows a Poor Response to Gemcitabine-Based Chemotherapy.

OBJECTIVES: Pancreatic ductal adenocarcinoma with strong expression of interleukin-13 receptor α2 (IL-13Rα2) was associated with poor prognosis and gemcitabine resistance in an orthotopic mouse model. We evaluated the influence of IL-13Rα2 expression in the endoscopic ultrasound-fine needle aspiration (EUS-FNA) specimen. METHODS: We included patients with pancreatic ductal adenocarcinoma, as diagnosed by EUS-FNA, who received gemcitabine-based chemotherapy (G-CTX). Tumor expression of IL-13Rα2 was assessed by immunohistochemistry and classified using a three scale (negative, weak, or strong) in a blinded fashion. The effect of G-CTX was assessed by tumor reduction rate by computed tomography after 3 months. RESULTS: A total of 95 patients were enrolled, and 63 and 32 cases were determined with strong and weak/negative expression of IL-13Rα2. The IL-13Rα2-strong group showed significantly poorer progression-free and overall survival rates than weak/negative group (P = 0.0191 and P = 0.0062, respectively). Strong expression of IL-13Rα2 was associated with progression factor after 3 months of the first G-CTX (odds ratio, 13.72; P = 0.0143). CONCLUSIONS: Pancreatic ductal adenocarcinoma with strong expression of IL-13Rα2 in EUS-FNA specimens showed poor prognosis and poor response to G-CTX.

Impact of the Coronavirus Disease-2019 Pandemic on Pancreaticobiliary Disease Detection and Treatment.

The emergency declaration (ED) associated with the coronavirus disease-2019 (COVID-19) pandemic in Japan had a major effect on the management of gastrointestinal endoscopy. We retrospectively compared the number of pancreaticobiliary endoscopies and newly diagnosed pancreaticobiliary cancers before (1 April 2018 to 6 April 2020), during (7 April to 25 May 2020), and after the ED (26 May to 31 July). Multiple comparisons of the three groups were performed with respect to the presence or absence of symptoms and clinical disease stage. There were no significant differences among the three groups (Before/During/After the ED) in the mean number of diagnoses of pancreatic cancer and biliary cancer per month in each period (8.0/7.5/7.5 cases, p = 0.5, and 4.0/3.5/3.0 cases, p = 0.9, respectively). There were no significant differences among the three groups in the number of pancreaticobiliary endoscopies (EUS: endoscopic ultrasonography/ERCP: endoscopic retrograde cholangiopancreatography) per month (67.8/62.5/69.0 cases, p = 0.7 and 89.8/51.5/86.0 cases, p = 0.06, respectively), whereas the number of EUS cases decreased by 42.7% between before and during the ED. There were no significant differences among the three groups in the presence or absence of symptoms at diagnosis or clinical disease stage. There was no significant reduction in the newly diagnosed pancreaticobiliary cancer, even during the ED. The number of ERCP cases was not significantly reduced as a result of urgent procedures, but the number of EUS cases was significantly reduced.

Duration of Reduced CA19-9 Levels Is a Better Prognostic Factor Than Its Rate of Reduction for Unresectable Locally Advanced Pancreatic Cancer.

A decrease in carbohydrate antigen (CA) 19-9 levels has been proposed as a prognostic marker for survival and recurrence in patients with pancreatic cancer. We evaluated the association between duration of reduced CA 19-9 levels during 6 months after treatment and long-term survival for 79 patients with unresectable locally advanced pancreatic cancer (LAPC). We calculated the differences between pretreatment and monthly CA19-9 levels. We categorized 71 patients with decreases in CA19-9 levels into three groups based on the duration of these reduced levels (>2, >3, and >4 months). The cut-off level for long-term (more than 2 years) survival was identified as a 44% reduction from the baseline, using a ROC curve. A reduction duration >2 months was not associated with overall survival (p = 0.1), while >3 months was significantly associated with survival (p =.04). In multivariate analysis, a reduction duration >3 months predicted a good long-term prognosis (odds ratio = 5.75; 95% confidence interval = 1.47-22.36; p < 0.01). In patients with unresectable LAPC, the duration of reduced CA19-9 levels for more than 3 months, rather than the rate of reduction in CA19-9 levels, during 6 months after treatment was significantly associated with good prognosis.

Usefulness of Routine Plain CT the Day After an Interventional EUS Procedure.

BACKGROUND: Interventional endoscopic ultrasound-guided procedures (I-EUS) are widely accepted as salvage procedures in ERCP-failed cases, and to drain fluid collected in the abdominal cavity. Although I-EUS has a relatively high incidence of complications and is severe/fatal in some cases, no follow-up strategy has been established. In our institution, plain computed tomography (P-CT) is performed routinely the day after I-EUS. In this study, we evaluated the usefulness of routine P-CT the day after I-EUS, as a follow-up method, and propose an algorithm. METHODS: We retrospectively reviewed 81 patients who underwent I-EUS and evaluated the usefulness of P-CT, abdominal X-ray, laboratory data, and symptoms as a follow-up method. An adverse event (AE) was defined as an event requiring any treatment. RESULTS: Technical success, clinical success, and AE rates were 96.3%, 90.1%, and 18.9%, respectively. In total, 30 patients had abnormal findings among the follow-up methods: 6 cases underwent additional procedures, 8 underwent medical treatments, and 16 were observed. The sensitivity, specificity, and accuracy for detecting AEs were assessed based on P-CT (85.7%, 100%, and 97.5%), X-ray (7.1%, 100%, and 83.5%), laboratory data (71.4%, 83.0%, and 81.0%), and symptoms (92.9%, 86.2%, and 87.3%). The sensitivity and accuracy of the latter two items were as high as those for X-ray, but specificity was lower than those for X-ray and P-CT. CONCLUSIONS: Routine P-CT the day after I-EUS was useful for detecting complications and deciding to perform an invasive salvage procedure. Symptoms and laboratory data were useful to supplement routine P-CT.

Risk Factors for Stent Migration into the Abdominal Cavity after Endoscopic Ultrasound-Guided Hepaticogastrostomy.

Background: Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is becoming increasingly popular. However, the risk factors for stent migration into the abdominal cavity remain unknown. Methods: Forty-eight patients undergoing EUS-HGS with placement of a long, partially covered self-expandable metallic stent (LPC-SEMS) were studied retrospectively to identify risk factors of stent migration. We determined the technical and functional success rates, and recorded adverse events, including stent migration. Results: EUS-HGS was technically successful in all patients. However, stent migration was evident in five patients (one actual and four imminent, 10%). Stent migration into the abdominal cavity was observed in one patient (2%), and the other four cases required additional procedures to prevent migration (8%). Logistic regression analysis revealed that the risk of stent migration increased as the initial (pre-procedure) distance between the stomach and liver at the puncture site increased (p = 0.012). Conclusions: A longer distance between the stomach and liver at the puncture site increased the risk of stent migration. However, during EUS-HGS, it is difficult to adjust the puncture position. It is important to ensure that the proportion of the stent in the stomach is large; the use of a self-anchoring stent may be optimal.

Evaluation of the Feasibility and Effectiveness of Placement of Fully Covered Self-Expandable Metallic Stents via Various Insertion Routes for Benign Biliary Strictures.

BACKGROUND AND AIMS: The goals of the management of benign biliary stricture (BBS) are to relieve symptoms and resolve short-/long-term stricture. We performed fully covered self-expandable metallic stent (hereafter, FCSEMS) placement for BBS using various methods and investigated the treatment outcomes and adverse events (AEs). METHODS: We retrospectively studied patients who underwent FCSEMS placement for refractory BBS through various approaches between January 2017 and February 2020. FCSEMS were placed for 6 months, and an additional FCSEMS was placed if the stricture had not improved. Technical success rate, stricture resolution rate, and AE were measured. RESULTS: A total of 26 patients with BBSs that were difficult to manage with plastic stents were included. The mean overall follow-up period was 43.3 ± 30.7 months. The cause of stricture was postoperative (46%), inflammatory (31%), and chronic pancreatitis (23%). There were four insertion methods: endoscopic with duodenoscopy, with enteroscopy, EUS-guided transmural, and percutaneous transhepatic. The technical success rate was 100%, without any AE. Stricture resolution was obtained in 19 (83%) of 23 cases, except for three cases of death due to other causes. Stent migration and cholangitis occurred in 23% and 6.3%, respectively. Stent fracture occurred in two cases in which FCSEMSs were placed for more than 6 months (7.2 and 10.3 months). CONCLUSION: FCSEMS placement for refractory BBS via various insertion routes was feasible and effective. FCSEMSs should be exchanged every 6 months until stricture resolution because of stent durability. Further prospective study for confirmation is required, particularly regarding EUS-guided FCSEMS placement.

Endoscopic ultrasound-guided antegrade procedures for managing bile duct stones in patients with surgically altered anatomy: Comparison with double-balloon enteroscopy-assisted endoscopic retrograde cholangiography (with video).

BACKGROUND AND STUDY AIM: Management of bile duct stones (BDSs) in patients with surgically altered anatomies (SAAs) remains challenging. An endoscopic ultrasound-guided antegrade (EUS-AG) procedure and double-balloon enteroscopy-assisted endoscopic retrograde cholangiography (DB-ERC) have been used to remove BDSs from patients with SAAs. However, few comparative data have been reported. Therefore, we compared the efficacy and safety of the techniques. METHODS: This was a single-center retrospective study. Patients with SAA who underwent the EUS-AG procedure or DB-ERC to remove intra- or extra-BDSs between November 2010 and March 2020 were included. The primary outcome was the technical success rate, defined as stent insertion or stone removal during the initial session. The secondary outcomes were the procedure time, incidence of adverse events (AEs), and complete stone removal rate. RESULTS: Of the 54 patients enrolled, 23 underwent the EUS-AG procedure and 31 DB-ERC. The technical success rates of EUS-AG and DB-ERC were 87.0% and 64.5%, respectively (P = 0.11). The procedure time was significantly shorter in the EUS-AG group than in the DB-ERC group (51.9 ± 15.4 vs 72.6 ± 32.2 min; P = 0.01), and the early AE rates were 26.1% and 12.9%, respectively (P = 0.71). The complete stone removal rates in patients who underwent previous stone removal were 94.1% in the EUS-AG group and 85.7% in the DB-ERC group (P = 0.61). CONCLUSION: The EUS-AG afforded technical success and complete stone removal rates comparable with those of DB-ERC, but the former procedure was shorter. The AE rate was acceptable.

Clinical Evaluation of a Newly Developed Guidewire for Pancreatobiliary Endoscopy.

BACKGROUND: The guidewire (GW) plays an important role in pancreatobiliary endoscopy. GW quality is a critical factor in the effectiveness and efficiency of pancreatobiliary endoscopy. In this study, we evaluate a new 0.025 inch multipurpose endoscopic GW: the M-Through. METHODS: Our study was a multicenter retrospective analysis. We enrolled patients who underwent endoscopic procedures using the M-Through between May 2018 and April 2020. Patients receiving the following endoscopic treatments were enrolled: common bile duct (CBD) stone extraction, endoscopic drainage for distal and hilar malignant biliary obstruction (MBO), and endoscopic drainage for acute cholecystitis. For each procedure, we examined the rate of success without GW exchange. RESULTS: A total of 170 patients (80 with CBD stones, 60 with MBO, and 30 with cholecystitis) were enrolled. The rate of completion without GW exchange was 100% for CBD stone extraction, 83.3% for endoscopic drainage for MBO, and 43.3% for endoscopic drainage for cholecystitis. In unsuccessful cholecystitis cases with the original GW manipulator, 1 of 8 cases succeeded in the manipulator exchange. Including 6 cases who changed GW after the manipulator exchange, 11 of 16 cases succeeded in changing GW. There was significant difference in the success rate between the manipulator exchange and GW exchange (p = 0.03). The insertion of devices and stent placement after biliary cannulation (regardless of type) were almost completed with M-through. We observed no intraoperative GW-related adverse events such as perforation and bleeding due to manipulation. CONCLUSION: The 0.025 inch M-Through can be used for endoscopic retrograde cholangiopancreatography-related procedures efficiently and safely. Our study found high rates of success without GW exchange in all procedures except for endoscopic drainage for cholecystitis. This GW is considered (1) excellent for supportability of device insertion to remove CBD stones; (2) good for seeking the biliary malignant stricture but sometimes need the help of a hydrophilic GW; (3) suboptimal for gallbladder drainage that require a high level of seeking ability.

Endoscopic Ultrasonography Findings of Early and Suspected Early Chronic Pancreatitis.

Chronic pancreatitis (CP) is associated with a risk of pancreatic cancer and is characterized by irreversible morphological changes, fibrosis, calcification, and exocrine and endocrine insufficiency. CP is a progressive disease with a poor prognosis and is typically diagnosed at an advanced stage. The Japan Pancreas Society proposed criteria for early CP in 2009, and their usefulness has been reported. Recently, a mechanism definition was proposed by the International Consensus Guidelines and early CP was defined as a disease state that is not based on disease duration. CP is diagnosed by computed tomography, magnetic resonance imaging, and endoscopic cholangiopancreatography, which can detect calcification and dilation of the pancreatic ducts; however, detecting early CP with these modalities is difficult because subtle changes in early CP occur before established CP or end-stage CP. Endoscopic ultrasonography (EUS) is useful in the diagnosis of early CP because it allows high-resolution, close-up observation of the pancreas. In addition to imaging findings, EUS with elastography enables measurement of the stiffness of the pancreas, an objective diagnostic measure. Understanding the EUS findings of early CP is important because a histological diagnosis is problematic, and other modalities are not capable of detecting subtle changes in early CP.

Best Procedure for the Management of Common Bile Duct Stones via the Papilla: Literature Review and Analysis of Procedural Efficacy and Safety.

BACKGROUND: Endoscopic management of common bile duct stones (CBDS) is standard; however, various techniques are performed via the papilla, and the best procedure in terms of both efficacy and safety has not been determined. METHODS: Endoscopic procedures were classified into five categories according to endoscopic sphincterotomy (EST) and balloon dilation (BD): (1) EST, (2) endoscopic papillary BD (≤10 mm) (EPBD), (3) EST followed by BD (≤10 mm) (ESBD), (4) endoscopic papillary large BD (≥12 mm) (EPLBD), and (5) EST followed by large BD (≥12 mm) (ESLBD). We performed a literature review of prospective and retrospective studies to compare efficacy and adverse events (AEs). Each procedure was associated with different efficacy and AE profiles. RESULTS: In total, 19 prospective and seven retrospective studies with a total of 3930 patients were included in this study. For EST, the complete stone removal rate at the first session, rate of mechanical lithotripsy (ML), and rate of overall AEs in EST were superior to EPBD, but a higher rate of bleeding was found for EST. Based on one retrospective study, complete stone removal rate at the first session, rate of ML, and rate of overall AEs were superior for ESBD vs. EST, and the rate of bleeding for the former was also lower. Complete stone removal rate at the first session and rate of ML for ESLBD were superior to those for EST, with no significant difference in rate of AEs. For EST vs. EPLBD, complete stone removal rate at the first session and rate of ML were superior for the latter. For EPLBD vs. ESLBD, the efficacy and safety were similar. CONCLUSIONS: ESBD is considered the best procedure for the management of small CBDS, but strong evidence is lacking. For large CBDS, both ESLBD and EPLBD are similar.

Mucinous Cystadenocarcinoma of the Pancreas with Cyst Infection in a Male Patient.

Follow-up computed tomography revealed a 40-mm pancreatic tail cyst in a 59-year-old man with type 1 diabetes mellitus. An intraductal papillary mucinous neoplasm was suspected; mucinous cystic neoplasm (MCN) was not considered because the patient was a man. During follow-up, cyst infection occurred but was improved by conservative treatment. At the 24-month follow up examination, cyst nodules had developed, corresponding to an increase in the carbohydrate antigen 19-9 level. Mucinous cystadenocarcinoma (MCC) was diagnosed pathologically based on distal pancreatectomy. A diagnosis of male MCN/MCC is often delayed, which may lead to a poor prognosis. MCN infection is also rare and poorly recognized. We observed an atypical male case of MCN/MCC.

Evaluation of the safety and efficacy of minimal endoscopic sphincterotomy followed by papillary balloon dilation for the removal of common bile duct stones.

BACKGROUND/AIM: A sufficiently open papilla is needed to remove common bile duct stones (CBDS) but endoscopic sphincterotomy (EST) requires a high level of skill and is difficult with endoscopic papillary balloon dilation (EPBD). The main adverse event of EST is bleeding and perforation and that of EPBD is post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis. To reduce these adverse events we employed minimal EST followed by papillary dilation (ESBD), and retrospectively evaluated its efficacy and safety compared with EST. PATIENTS AND METHODS: CBDS patients who underwent EST (n = 114) or ESBD (n = 321) at Juntendo University Hospital from January 2009 to December 2018 were consecutively enrolled, retrospectively. The exclusion criteria were large-balloon dilation (≥ 12 mm), large CBDS (>12 mm), and previous EST/EPBD. We compared the overall stone removal rate, incidence of adverse event, procedure time, number of ERCP procedures, and rate of mechanical lithotripsy (ML) between the two groups. RESULTS: Complete stone removal was successful in both ESBD and EST group. However, the rate of multiple ERCP sessions was significantly lower (35.1% vs. 12.8%, P < 0.001), procedure time was shorter (31.6 vs. 25.8 min, P = 0.01), and rate of ML was lower (16.7% vs. 7.8%, P = 0.01) in ESBD group. Bleeding was significantly more frequent in the EST group (9.6% vs. 1.2%, P < 0.001), particularly acute bleeding (7.9% vs. 0.9%, P < 0.001). CONCLUSIONS: ESBD is more efficient and safer in the management of CBD stones than EST. A prospective randomized study comparing ESBD with EST is needed to establish this combination technique.

Role of Peroral Cholangioscopy in the Diagnosis of Primary Sclerosing Cholangitis.

Primary sclerosing cholangitis (PSC) is characterized by idiopathic biliary stricture followed by progressive cholestasis and fibrosis. When diagnosing PSC, its differentiation from other types of sclerosing cholangitis and cholangiocarcinoma is necessary. The cholangioscopic findings of PSC have not been investigated sufficiently. PSC and IgG4-related sclerosing cholangitis are difficult to distinguish by peroral cholangioscopy (POCS), but POCS is useful for excluding cholangiocarcinoma. POCS findings vary according to the condition and stage of disease. In the active phase, findings such as mucosal erythema, ulceration, fibrinous white exudate, and an irregular surface are observed and may reflect strong inflammation in the biliary epithelium. On the other hand, findings such as scarring, pseudodiverticula, and bile duct stenosis appear in the chronic phase and may reflect fibrosis and stenosis resulting from repeated inflammation. Observation of inside the bile duct by POCS might confirm the current PSC activity. Because POCS offers not only information regarding the diagnosis of PSC and PSC-associated cholangiocarcinoma but also the current statuses of biliary inflammation and stenosis, POCS could significantly contribute to the diagnosis and treatment of PSC once the characteristic findings of PSC are confirmed by future studies.