Laparoscopic cholecystectomy was performed after percutaneous transhepatic gallbladder drainage in approximately 50% of cases with mild and 80% of cases with moderate acute cholecystitis in our hospital. Biliary drainage was transpapillary in 90%, percutaneous in 9%, and transpapillary and percutaneous in 1% of the cases. Endotoxin excretion into bile juice was observed in 90% of bile tract infection caused by gram-negative bacilli. For common bile duct stones, 99.8% were endoscopically treated, and the breakdown was 95% transpapillary and 5% percutaneous; 0.2% of cases were surgically treated. In the drainage of transpapillary treatment, there was no significant difference in the drainage effect between endoscopic biliary stenting and endoscopic nasobiliary drainage. The factors contributing to post-EST bleeding and pancreatitis were hypertension and small-incision EST, respectively. The incidence of post-EST bleeding in antithrombotic drug users was 9%, and the contributing factor was EST incision direction (11 o'clock direction). In percutaneous treatment, about 80% of the cases underwent stone removal after elctrohydraulic lithotripsy. The cumulative stone recurrence rate was 14% in 3 years; however, all recurrence stones could be removed under percutaneous transhepatic cholangioscopy.

Clinical research is established by providing samples and/or data based on the patient's goodwill. So, researchers are responsible for not wasting their samples and data, and conducting research requires ethics, social significance, and scientific validity. Researchers are required to attend seminars. And, researchers must prepare a "research plan" prior to research and be examined by the ethics review committee. In order to obtain consent, it is a general rule to obtain sufficient explanation and free will consent from the patients. If it is impossible to obtain consent in a study that uses existing samples and information obtained in clinical practice or another study, it can be conducted by opt-out.

The endoscopic therapy for pancreatobiliary diseases in patients with surgically altered anatomy had been not practical until the applied use of balloon-assisted endoscope (BAE) that was originally developed as an enteroscopy made it feasible. Since the medical procedural addition points of the ERCP using BAE (BAE-ERCP) were promulgated in Japanese national health insurance, BAE-ERCP has become the first-line pancreaobiliary endoscopic treatment for postoperative cases, however, the procedure is yet to be standardized. The deep endoscopic insertion into the blind end and the ERCP-related interventions are both required to complete BAE-ERCP. The first step of ERCP-related procedures is biliary cannulation. There are two ways of accesses to biliary cannulation, one is via the papillary approach and the other is via the choledochojejunal approach. It is important to thoroughly comprehend the basics and the features of respective accesses to aim to accomplish the BAE-ERCP procedures.

We examined the histopathological features of incidental gallbladder cancer (IGBC). We analyzed the 15 cases of IGBC (6 cases of early stage, 9 cases of advanced stage) and the incidence was 2.7%. Compared with 19 cases of conventional gallbladder cancer (CGBC), gallstones tended to be more complicated in the advanced IGBC group than in CGBC, and wall thickening was lower (P=0.034). These results were considered to be a factor that makes image diagnosis difficult. Although there were no differences between IGBC and CGBC in terms of lymphatic or venous invasion and prognosis, 6 cases in the early stage disease group showed no lymphatic invasion or venous invasion, and only one case experienced a postoperative recurrence. Since the clinical course of IGBC differs according to the stage at the time of diagnosis, it is important to perform additional examination in whole tissue section and carefully perform staging.

IgG4-related sclerosing cholangitis (IgG4-SC) is a distinct type of cholangitis frequently associated with autoimmune pancreatitis around 70-90% of all and currently recognized as a biliary manifestation of IgG4-related disease. The therapeutic strategy for IgG4-SC, which sometimes presented without AIP, is applied to that of AIP in real situation. A clinical practical guideline 2019 for IgG4-SC was established, while there has been devoid of evidence such as characteristics of isolated type, long-term prognosis included cancerization, the feasibility and safety of the steroid and its pathogen.This guideline proceeded by experts was developed based on the consensus, which was decided by the modified Delphi approach to enhance its low evidence level. As such, hopefully, this guide could be a permanently reliable standard which would lead to the world consensus concerning the therapeutic strategy for IgG4-SC by making frequent revises with plausible evidence and promising biomarkers without cease our dedications.

Systemic therapy for biliary tract cancer is often administered as perioperative adjuvant therapy, or as palliative therapy in cases with unresectable disease. Capecitabine is widely used overseas as postoperative adjuvant therapy, but this drug is still not approved for this use in Japan. Combined gemcitabine plus cisplatin, gemcitabine plus S-1, and gemcitabine plus cisplatin plus S-1 have been established as standard first-line treatments. Modified FOLFOX was demonstrated to yield survival benefit as second-line treatment in a UK phase III trial, and it was often used in patients who showed disease progression after gemcitabine plus cisplatin therapy. However, this treatment is not covered by insurance in Japan. In recent years, the development of molecular-targeted agents based on genomic alterations in the tumors has been progressing, and favorable treatment efficacies have been reported with IDH1 inhibitors, FGFR inhibitors, BRAF inhibitors plus MEK inhibitors, HER2 inhibitors, etc. Furthermore, development of a promising immune checkpoint inhibitor is also in progress. Pembrolizumab for microsatellite instability high tumors and ROS1/TRK inhibitors against tumors with NTRK1/2/3 fusion can be administered across cancers in various organs. Thus, it appears that rapid progress is being made in the development of systemic therapies for biliary tract cancer.

With the advent of AI technology, many trials for medical purpose have started. Regarding the field of AI medical imaging, two major ways are CADe for the detection of the lesions, and CADx for the diagnosis. Moreover, some case reports are available in CAP (Computer-aid Prediction) especially in the field of optical fundus and mammary gland.

There are two issues for AI research in the field of biliary tract diseases coming up as follows: 1. Each modality is more likely to have lesion-specific detectability. e.g. CT-negative bile duct stones are often detectable using extracorporeal and endoscopic ultrasound. 2. Pre-treatment diagnosis is often made by the results from multiple modalities.

To solve these problems, the authors recommend the Japan Biliary Association firstly collect the big data including the images and texts from all kinds of biliary related modalities, and start with CADe for the lesion-specific detectability in the dedicated modalities and CADx using AI algorithm generated from those data. GAN and cluster technology would be of great help for rare biliary diseases.

The authors expect the future AI research in the biliary tract diseases fruitful.

81-year-old man had complaints of jaundice and fever, and was diagnosed with distal cholangiocarcinoma the result of enhanced CT and the biopsy with ERC. The surgical treatment was performed, and tumors showed adenocarcinoma in the biliary epithelium, and neuroendocrine carcinoma in the submucosal infiltrating lesion. Adenocarcinoma components and neuroendocrine carcinoma components accounted for more than 30% each, and the diagnosis was mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). After the operation, the chemotherapy was performed, but died after 20 months. MiNEN of bile duct is difficult to differentiate before operations. The gold standard treatment for this disease has not been established and not only surgical treatment but also multimodal treatment such as preoperative chemotherapy may be considered.

Congenital defect of the gallbladder is a relatively rare disease. It is difficult to make a preoperative diagnosis of the disease even today since the development of image diagnosis, and actually, many cases are still diagnosed during surgery. Herein, we report our experience in a patient who was introduced to our hospital for cholecystolithiasis suggested by ultrasound, and diagnosed as having a defect of the gallbladder after we performed laparoscopic examination of the peritoneal cavity of the patient. The case was a 39-year-old female patient who visited a nearby hospital to undergo further examination for hepatic dysfunction, which was suggested in a health checkup, and cholecystolithiasis, which was suggested by ultrasound. She was introduced to our hospital for close examination despite showing no symptoms of cholecystolithiasis. CT suggested changes caused by cholecystolithiasis and contracted gallbladder; although the gallbladder was not visualized. Laparoscopic examination of the peritoneal cavity was not able to confirm the gallbladder, and thus it was diagnosed as congenital defect of the gallbladder.

We report a case of well-differentiated adenocarcinoma of the duodenal papilla which was strongly suspected to disseminate from intraductal papillary mucinous carcinoma (IPMC) via the pancreatic duct by genetic analysis. The patient was an octogenarian male with jaundice. Endoscopic examination revealed mild swelling of the duodenal papilla with sclerosis of the surrounding duodenal wall. A histopathological diagnosis of adenocarcinoma was confirmed by transampullary biopsy, and subtotal stomach-preserving pancreaticoduodenectomy was performed. Pathologically, well-differentiated adenocarcinoma with the gastric phenotype (MUC5AC+, MUC6+) and negative SMAD4-immunoreactivity replaced the epithelium of the ampulla, and invasion was seen into the surrounding stroma. IPMN was found in the branch duct but was microscopically discontinuous with the ampullary tumor. On the contrary, both lesions have same mutations in KRAS G13D and GNAS R201H, which indicated the ampullary carcinoma originated from IPMC lesion and was strongly suspected to disseminate via the pancreatic duct.

A 70-year-old man undergoing chemotherapy for gallbladder cancer was admitted for cholangitis due to bile duct stent occlusion. On CT, there was a gallbladder-colonic fistula, which formed a mass abscess with the tumor, and the content was like stool with gas. The patient was diagnosed with cholangitis and abscess formation, and it was considered that gallbladder cancer invaded the transverse colon, the internal pressure of the oral-side was increased, and a gallbladder-colonic fistula was formed.

Biliary drainage was preceded, and then a large intestine stent was placed in the transverse colon to reduce the pressure. The abscess disappeared and he was discharged to his home on the 20th day of after admitted. In unresectable advanced gallbladder cancer with no prognosis, colonic stent placement for internal bile fistula secondary to colonic invasion could be one of the treatments for infection control.

We report one case each of Csendes classification type II and type III Mirizzi syndrome. Case 1 is a 35-year-old woman. The chief complaint is epigastric pain. In the operation, the neck of the gallbladder was cut open in the longitudinal direction toward the dorsal side of the bile duct to remove the stone. At that time, a gallbladder-bile duct fistula was confirmed. The gallbladder neck was then trimmed and the stump closed with a nodular suture. Case 2 is a 75-year-old woman. The chief complaint is jaundice. The patient was diagnosed with Csendes classification type III of Mirizzi syndrome and underwent surgery. After removing the stones at the confluence and the bile duct, the bile duct wall was repaired using the gallbladder neck left in a flap shape, and the T tube was stented and placed. The course was good in both cases without postoperative bile duct stenosis.

The patient was a man in his 60s with obstructive jaundice. CT and ERCP revealed that the malignant biliary obstruction was caused by a carcinoma of the pancreatic head. For treating the jaundice, we performed ERCP and inserted a 10-Fr plastic stent into the common bile duct. One month later, he was admitted for cholangitis accompanied with stent occlusion. When we performed ERCP, we detected an obstruction of the plastic stent due to tissue-ingrowth from the flap on the papillary side of the stent. Therefore, we removed the plastic stent and inserted a fully-covered metallic stent. After this procedure, the cholangitis improved.

Plastic-stent occlusion usually occurs due to sludge formation, positioning error, and/or blood clots. Plastic-stent occlusion because of tissue-ingrowth is a very rare phenomenon.

Endoscopic sphincterotomy (EST) is the most established endoscopic treatment in terms of usefulness and safety, about 50 years after its development. However, since it is an area where adverse events (AE) occur frequently in gastrointestinal endoscopic treatment, it is necessary to master the procedure and acquire countermeasures for AE. In this article, I explained the basic techniques and tips of EST.