The reason I became interested in biliary tract was the clinical research "Change of free radicals during obstructive jaundice". Superoxide dismutase generated at obstructive jaundice was measured, and it was examined whether it was possible to distinguish a group with poor reduction of jaundice. At the time of obstructive jaundice, the outflow of activated neutrophils into peripheral blood accompanying the increase in the ability to produce active oxygen was promoted. In addition, lipid peroxide in the obstructive jaundice group showed a high value, and it was considered that hepatocyte function was reduced due to increased lipid peroxide production activity in the liver. I was able to get involved in national biliary tract cancer registry and revision of classification of biliary tract cancer. The number of registered cases became big data of 35225 cases. In a study of biliary tract cancer registration, hepatectomy of the S4a+5 segment and gallbladder bed resection for T2 gallbladder carcinoma were compared, and there was no significant difference in prognosis. In addition, a study of the national biliary tract cancer registration and UICC staging showed that gallbladder cancer should include the 13a lymph node in the regional lymph node. The biliary tract cancer registry will be transferred to NCD along with the revision of classification of biliary tract cancer (7th edition), and preparations are being made to accumulate more cases.

Pancreaticobiliary maljunction (PBM) is defined as a congenital malformation in which the pancreatic and bile ducts join outside the duodenal wall. Congenital biliary dilatation (CBD) is defined as a malformation which has both extrahepatic biliary dilatation and PBM. PBM causes reciprocal regurgitation of bile and pancreatic juice, which produces intermittent symptoms during childhood and biliary carcinoma in adulthood. Symptoms of abdominal pain and vomiting are caused by transient obstruction in the common bile duct with protein plugs. Plugs consist of insoluble lithostathine cleaved by trypsin, both of which are regurgitated from the pancreas. Biliary cancers are caused by chronic irritation of hazardous substances, produced by mixture of bile and pancreatic juice. Prevention of regurgitation and resection of organs tend to suffer from biliary cancer is necessary for treatment. Treatment of CBD involves bile duct resection and separation of bile and pancreatic juice. Complete excision of intrapancreatic bile duct and treatment of congenital intrahepatic bile duct stenoses are necessary to prevent later complication.

EUS and IDUS are positioned as Third steps in the Clinical practice guidelines for management of biliary tract cancers 2019: the 3rd Japanese edition.

In biliary tract cancers, EUS, ERCP, biopsy, cytology, and PET are performed. In addition, POCS and IDUS for bile duct cancer, POCS for gallbladder cancer, and IDUS for cancer of the Ampulla of Vater are performed.

Bile duct cancer: EUS is useful for differential diagnosis and the longitudinal tumor extent diagnosis, and IDUS can accurately diagnose local tumor staging, vascular invasion (portal vein, right hepatic artery), and the longitudinal tumor extent.

Gallbladder cancer: EUS is useful for the diagnosis of pancreatic invasion, the depth of tumor invasion into the wall of the gallbladder.

Cancer of the Ampulla of Vater: EUS is useful for the diagnosis of tumor invasion into the pancreatic parenchyma, and IDUS can accurately diagnose T staging and evaluating ductal invasion.

EUS-FNA recommends that patients with unresectable bile duct cancer and unresectable gallbladder cancer should be performed with caution as necessary.

In the Tokyo Guidelines 2018, safe steps for laparoscopic cholecystectomy (LC) for acute cholecystitis are shown. Among these, the recommendation to choose bailout procedures to avoid bile duct damage in patients in whom the surgery would be difficult is included.

LC is most difficult in patients with chronic cholecystitis, in which the layers of the gallbladder wall have disappeared and become scarred due to repeated cholecystitis. If ablation at the Calot's triangle is difficult, a fundus first technique wherein an incision is made from the fundus of the gallbladder toward the neck should be selected. If ablation of the cystic duct is difficult, a subtotal cholecystectomy should be performed. Although an open conversion can be performed in some cases when surgery is challenging, it cannot always be said that the LC technique will become easier with open conversion. The decision to perform these bailout procedures should be made appropriately considering the skill of the surgeon.

ERCP and associated procedures are widely used for the management of biliary disorders. Successful biliary cannulation is the initial mandatory step for all subsequent procedures. Achieving deep biliary cannulation can be challenging at times for experts and novices alike. The techniques available for cannulation have expanded. Several alternative techniques have been attempted after failed initial biliary cannulation using the routine techniques. Pancreatic guidewire technique may be most popular as a first salvage technique, followed by several precut techniques. Moreover, use of EUS guided rendezvous technique has also been recently increasing. It is necessary to become familiar with a variety of the newer techniques already available. We should not repeat the same approach and try to use alternative techniques which are tailored to the individual papillary and ductal anatomy of each patient.

We evaluated SpyGlass DS for longitudinal extensions of bile duct cancer. The present study included 17 patients underwent a surgical line of resection (15 resections, 2 unresections). We compared the accuracy of diagnosing longitudinal extensions using computed tomography (CT), intraductal ultrasonography (IDUS), cholangiography, and SpyGlass DS.

In resected cases, the false-positive rate was 6.7% for CT, 25.0% for IDUS, and 20.0% for cholangiography. The findings of Cholangioscopy-guided biopsies revealed normal mucosa in 86.7% of cases, irregular mucosa in 13.3%, and not carcinoma. R0 resection was achieved in all cases, with SpyGlass DS showing a diagnostic accuracy of 100%. For unresected cases, positive rates were 50.0% for CT, 50.0% for IDUS, and 100% for cholangiography. The findings of cholangioscopy-guided biopsies showed carcinomas, diagnosed as unresectable.

The findings of SpyGlass DS cholangioscopy-guided biopsies are useful for evaluating longitudinal extensions of bile duct cancer.

The aim of this study was to evaluate the possibility on detection of cystic duct lesions by endoscopic ultrasonography (EUS). Consecutive 711 patients were attempted to demonstrate systematically biliary tract using curvilinear-array EUS. In these patients, the detected cystic duct lesions and the delineation capability of cystic duct were investigated. Thirty cystic duct lesions were found, of which 22 lesions were stones, 4 were carcinomas, 3 were adenomyomatosis, and 1 was a hyperplastic polyp. EUS demonstrated all lesions; however, the calculous/acalculous lesions in transabdominal US, computed tomography, magnetic resonance imaging were demonstrated in 0%/12.5%, 42.1%/85.7%, and 41.2%/75.0%, respectively. The frequent reason of performing EUS was the search of causes of cholecystitis/cholangitis/pancreatitis in calculous lesions, and the increase/appearance of stones/debris in gallbladder in acalculous lesions. Continuous observation of the cystic duct was achieved in 82.3% (585/711). The achievement rate rose to 93.6% (336/359) in the later study period from 70.7% (249/352) in the early study period. Curvilinear-array EUS has high delineation capability of cystic duct and the possibility of the detection of cystic duct lesions.

Endoscopic ultrasound-guided biliary drainage (EUS-BD) has been increasingly used as an alternative in patients with biliary obstruction who fail endoscopic retrograde cholangiopancreatography. The advantage of EUS-BD is one-step internal drainage, compared with percutaneous biliary drainage. Recent studies have revealed that cumulative technical success and adverse event rates were 82-100% and 0-21.2%, respectively. Several adverse events have been reported such as bleeding, perforation and peritonitis, which sometimes require surgical and radiological intervention. Therefore, we should understand the mechanism of adverse events and the technique to prevent and manage them. Here, we focus on the progress and problems of EUS-BD referring to articles which have been published until now.

Adenomyomatosis (ADM) of the gallbladder is a benign, acquired lesion characterized by proliferation of the Rokitansky-Aschoff sinus (RAS) with epithelial and muscular hypertrophy. ADM is classified into diffuse, segmental, fundal, and mixed type according to its distribution. In this manuscript, gallbladder ADM is described mainly from the viewpoint of pathology, and ADM cases experienced in our institution have been summarized. It is noteworthy that muscular hypertrophy is seen in ADM, but a RAS-surrounding pattern is undetectable. In segmental type ADM, muscular hypertrophy is sometimes more marked at the fundal side than at the ADM site. In fundal type ADM, the grossly detectable central pit is comprised of the depressed gallbladder wall itself and not of the RAS. The pathogenesis of ADM has not been formally established, although there seems to be a consensus on the histological step from RAS to ADM. Current data does not support ADM as a precursor lesion of gallbladder carcinoma, although several authors have reported ADM, particularly segmental ADM, as a risk factor. The collection of further evidence regarding ADM pathology is required.

A case is a woman in her 50's. She was transported to our hospital with liver injury caused by traffic trauma 9 years ago. The rupture at the origin of the left hepatic duct was found, and it was difficult to try internal fistula by PTBD. Maintenance hemodialysis was required during the course of treatment, hepatic resection was judged impossible. Therefore, we performed intrahepatic bile duct jejunostomy with a B3 bile duct (Longmire's operation). However, cholangitis symptoms appeared frequently in 7 years after surgery, and it became a diagnosis of intrahepatic choledocholithiasis. We judged it as a surgical indication and performed left hepatectomy. A postoperative bile fisture occurred but it cured conservatively and she was discharged on the 43 rd day.

Longmire surgery may be performed for biliary stricture which was incurable with IVR, but intrahepatic bile duct calculus may occur after long period as in this case. Therefore, careful follow-up observation was considered necessary.

A 66-year-old female was referred to our hospital to far examination for irregularity of gallbladder wall and dilatation of common hepatic duct (CHD) detected by ultrasonography. The previous medical history showed that the patient had splenectomy and esophageal transection for esophageal varices at the age of 41. Blood test revealed slightly elevation of serum bilirubin. Radiological findings revealed gallbladder stones, extrahepatic portal venous obstruction (EHPVO), cavernous transformation (CVT), stenosis of CBD and dilatation of CHD. CBD stenosis due to CVT formed by EHPVO was diagnosed. An endoscopic biliary drainage (EBD) tube was placed in the CBD for cholestasis. In spite of the EBD tube was lost one year later, serum bilirubin was normal and no deterioration was found with CBD.

The patient is healthy in 6 years later now.

A 70's-year-old man underwent ileocecal resection for cecal cancer (Stage II). 4 years later, enhanced CT scan showed dilation of intrahepatic bile duct (B2,3) with no obvious intrahepatic tumor lesion. An intrahepatic cholangiocarcinoma was suspected. Endoscopic cholangiography showed an obstruction of the intrahepatic bile duct at the origin of B2 and B3, and cytology examinations revealed a finding of adenocarcinoma. The immunohistochemical examination of CK7 and CK20 convinced the diagnosis of metastasis from the cecal cancer. Left hepatectomy with caudal lobectomy was performed. The pathological findings showed a papillary tumor about 2cm in size filled only within intrahepatic bike duct at the beginning of B2,3. The final pathological diagnosis was a metastatic tumor of cecal cancer. Left hepatectomy with caudal lobectomy was performed. 7 years after surgery, recurrence tumor hasn't been observed. When the recurrence of colorectal cancer in intrahepatic bile duct whose appearance resembles an intrahepatic cholangiocarcinoma was completely resected, long-term prognosis can be expected as shown in the present case.

A 70-years-old man with abdominal pain was referred to our hospital. Abdominal ultrasonography showed a polypoid lesion in the gallbladder. The lesion had no blood flow by contrast-enhanced CT and contrast-enhanced Ultrasonography. So we diagnosed that it was not neoplasm. Endoscopic ultrasonography showed the outermost hyperechoic layer pulling up inside to the gallbladder. Therefore we suspected gallbladder carcinoma. We performed bile cytology via the endoscopic transpapillary gallbladder drainage route. Pathological finding suggested adenocarcinoma. The liver bed and common bile duct resection was performed. The postoperative pathological findings revealed pT2 gallbladder adenocarcinoma with necrosis. It was difficult in the diagnosis using contrast-enhanced agents by obstruction of blood flow in the polypoid lesion. EUS was useful to diagnose gallbladder lesion without blood flow.

The biliary tract is a bile outflow tract. Most of the biliary tract cancers develop obstructive jaundice. Diagnosis of biliary tract cancer with obstructive jaundice is planned according to the algorithm of the guideline. In resectable cases, precise preoperative diagnosis is important for radical resection. In actual clinical practice at each institute, some of empirical factors may affect the determination of the strategy of the biliary drainage. ENBD after diagnostic ERCP-related procedures is preferable. EBD is acceptable when the management is difficult due to such as long preoperative waiting period. For unresectable cases, it is important to select a drainage method considering the availability of re-interventions.