IgG4-related sclerosing cholangitis (IgG4-SC) is characterized by an elevated serum IgG4 concentration and by extensive fibrosis and dense infiltration of the bile duct wall by IgG4-positive plasma cells. IgG4-SC can be carefully diagnosed based on the clinical diagnostic criteria for IgG4-SC proposed in 2012. Cholangiographic classification of IgG4-SC is useful for making the differential diagnosis between IgG4-SC and other diseases. When intrapancreatic bile duct stenosis is detected, pancreatic cancer and cholangiocarcinoma (CC) must be ruled out. If intrahepatic bile duct stenosis is observed at more than one site, primary sclerosing cholangitis (PSC) must be included in the differential diagnosis. If stenosis is demonstrated in the hilar region, CC should be ruled out. Cases of isolated IgG4-SC sometimes develop, and they are difficult to diagnose.

Steroid therapy is standard treatment. Oral prednisolone therapy is started at 0.6mg/kg/d for 2 or 4 weeks, and the dose is then gradually tapered. Although the outcome of most IgG4-SC patients has been reported to be good based on the strong responsiveness of IgG4-SC to steroid therapy, further study is needed to elucidate the long-term outcome.

Bile duct strictures may result from various malignant and benign reasons, and differentiating between a malignant and benign stricture is important in daily practice. Endoscopic retrograde cholangiopancreatography (ERCP) is the most widely used endoscopic procedure in evaluating bile duct strictures. ERCP related procedures include cholangiogram, intra-ductal ultrasonography, tissue samplings, and cholangioscopy. They provide high diagnostic accuracy for differentiate from benign and malignant stricture. In the bile duct cancer, preoperative clinical diagnosis of distant metastases and local extension including invasion of the vessels and longitudinal extension is important. The longitudinal tumor extension varies depending on the gross type and location of tumor. According to frequent intraluminal tumor extension in hilar or upper bile duct cancer; the findings of wall thickness by MDCT and tapering stenosis of the bile duct by detail cholangiography are interpreted with care about the limits of ductal resection of the residual liver lobe as an index. On the other hand, the superficial tumor extension is frequent in the middle or lower bile duct cancer; therefore, peroral cholagioscopy and biopsy are often necessary. ERCP related procedures play a great roll for diagnosis of bile duct cancer.

A gallstone is defined as a concrement present in the biliary tract consisting of the gallbladder and bile duct. Gallstone diseases are often encountered in daily clinical practice. In the natural history of gallstones, a follow-up survey for gallstone patients with no treatment showed that the probability of having biliary tract pain during the prospective evaluation was significantly increased in the patients who had a prior history of biliary tract pain compared to those who had no history of pain before. However, the majority of symptomatic gallstone patients do not persist biliary colic for a long time but take a peaceful natural course. In the natural history of asymptomatic gallstones, the incidence rate of severe complications is reportedly a few percent. Among the severe complications, the most frequent one is acute cholecystitis. The conversion rate from asymptomatic to symptomatic gallstone is the highest within a few years after the diagnosis is made, and the rate complications decreases in parallel to the observation period. Moreover, it has been reported that no occurrence of gallbladder cancer is found in the observation period. The corresponding manner for asymptomatic gallstone is generally advised to watch clinical course.

Background: Endoscopic transpapillary cytology and biopsy are currently performed in cases with malignant biliary lesions (MBLs). However, their diagnostic accuracies are unsatisfactory. We aimed to evaluate the diagnostic ability of EUS-FNA in cases with suspected MBLs.

Methods: The present study included 26 cases with suspected MBLs and without pancreatic cancer. There were 15 cases with MBLs, and 11 cases with lymphadenopathy around the common bile duct. EUS-FNA was performed in all cases. Of these 15 cases with MBLs, ERCP was performed in 12 cases prior to EUS-FNA. We compared EUS-FNA and ERCP tissue sampling for diagnosis.

Results: ERCP tissue sampling in 12 cases showed the sensitivity, the specificity, and the accuracy; 22%, 100%, and 30%, respectively. EUS-FNA in the same 12 cases improved those three factors; 93%, 100%, and 93%, respectively. No post-procedural complication was seen in any cases.

Conclusions: EUS-FNA is a safe and accurate diagnostic method for cases with suspected MBL, and may represent an additional option in cases with negative results diagnosed by ERCP tissue sampling.

'New classification of Japanese gallbladder stones' shows 'pure cholesterol stone', 'combination stone', 'mixed stone', 'calcium bilirubinate stone', 'black stone' and 'rare gallstone' like 'calcium carbonate stone' or 'fatty acid calcium stone'.

In our resected 225 cases of gallbladder stones, we have analyzed chemical component of each stones and compared with the findings in 'New classification of Japanese gallbladder stones'. Some 'pure cholesterol stones' contained calcium bilirubinate or calcium carbonate. While some part of 'mixed stones' showed 100% cholesterol component. The result of chemical analysis for cholesterol stones did not always agree with the 'classification'. Macroscopic findings of 'black stone' were seen in all kinds of chemically analyzed component. So to discuss or study about 'black stone', macroscopic classification is inadequate, and chemical componential analysis is needed.

Purpose: To consider how we can avoid unnecessary ERCP by incorporate a convex EUS in a diagnosis system for the case that transient cholangitis with the choledocholith is suspected.

Method: Reviewed 48 cases which were diagnosed as transient acute cholangitis after convex type EUS observation had been introduced in our hospital, we assessed a choledocholith rate of detection by convex type EUS.

Result: We had made an observation by EUS for all cases which were diagnosis of transient cholangitis and confirmed choledocholith in 10 cases (20.8%). After that we performed ERCP and succeeded choledocholith removal for all 10 cases.

Conclusion: As the result of EUS observation, we could detect the small choledocholith which hardly point out by the other examination and could figure out which are ERCP required cases.

To perform safe, accurate surgeries, preoperative images need to be thoroughly and carefully studied to envision the tumor location and the blood vessels to be dissected. Every surgeon experiences such preoperative work, which is part of the rigorous training they repeatedly receive from his instructor. However, a considerable number of years of training is required, especially in bile duct carcinoma surgeries, to understand the anatomically complex structures of the liver, hilar lesion, and pancreas. Moreover, sharing information between surgeons with differing years of experience has been difficult. However, with the tremendous development in imaging technology of recent years, 3-dimensional computed tomography images can be obtained relatively easily and preoperative simulation performed using these images. Since bile duct carcinoma surgeries are difficult and have a high rate of complications, preoperative simulation should be performed thoroughly to ensure that safe, accurate surgery can be provided.

Preoperative biliary drainage (PBD) for obstructive jaundice by low bile duct obstruction was reviewed concerning randomized prospective control studies, meta-analyses and clinical practice guidelines in Japan, Europe and the United States. Preoperative biliary drainage is not routinely necessary in patients with obstructive jaundice in the middle or lower bile duct. PBD should be done in obstructive jaundice with cholangitis. Self-expandable metallic stent seems to be rather useful than plastic stent. In pancreatic head cancer, preoperative adjuvant therapy is frequently done and PBD is performed before preoperative adjuvant therapy. Thus, stenting method and stenting apparatus are the targets of examination hereafter. In distal bile duct cancer, preoperative adjuvant therapy is not usually done. Thus, the presence or absence of PBD, stenting method, and stenting equipment are the questions of further examination including prospective study. Most evidences concerning PBD come from foreign countries. Evidences from Japan is expected carefully considering the clinical practices.

A 60-year-old male was referred to our hospital because of a repeated cholangitis and the dilation of left intrahepatic bile duct. An abdominal computerized tomography and the magnetic resonance cholangiopancreatography revealed the presence of multiple cystic lesions and mild bile duct dilation mainly in the left hepatic lobe, and hepatic left lobe atrophy. Endoscopic retrograde cholangiography showed a biliary stenosis of the left hepatic duct and irregular dilations of peripheral biliary branches. Direct cholangioscope showed an exclusion-like stenosis was detected in the left bile duct but the tumor vessels were absent. The malignant findings were absent from the cytology in bile and the biopsy obtained from biliary stenosis. In DIC-CT no communications were present between cystic lesions and bile ducts. A left hepatic lobectomy was performed based on a provisional diagnosis of hepatic peribiliary cysts. Although hepatic peribiliary cysts are sometimes difficult to distinguish from malignant lesions, these cysts has become to be diagnosed using various imaging modalities and treated conservatively due to benign disease itself. However surgical resection is thought to be one treatment choice for HPBC with repeated cholangitis in consideration of patient background.

A 76-year-old female was referred to our hospital for acute cholecystitis and right segmental cholangitis after placement of a SEMS, which was deployed to resolve bile duct strictures caused by unresectable hilar malignant tumor. Although the acute cholecystitis resolved by PTGBD, the PTGBD tube could not be removed because of severe outflow obstruction of the cystic duct. After completion of internal fistulization by EUS-GBD, the PTGBD tube could be removed. After the removal of the PTGBD tube, the patient's QOL was well maintained, and she was discharged. Internal fistulization using EUS-GBD after placement of a PTGBD tube might be useful in patients with cholecystitis following SEMS placement for bile duct strictures caused by unresectable malignant tumors.

91-year-old woman was admitted to our hospital for treatment of the bile duct stones. We performed EST, removed the stones with balloon catheter, and placed ENBD-tube. After that the patient complained severe abdominal pain and CT showed retroperitoneal perforation and acute pancreatitis. In consideration of the risk of surgical treatment, conservative therapy was performed. Unfortunately, infectious acute necrotic collection (ANC) was confirmed by CT on the 9th day after EST. Therefore, we deployed a fully-covered self-expandable metallic stent to close the fistula, and subsequently performed EUS-guided transgastric drainage. Inflammatory reaction was continued, and ANC changed to walled-off necrosis (WON). Thus, we added the treatment of endoscopic necrosectomy (EN) twice a week in 4 weeks. Finally, WON mostly disappeared and her condition completely improved.

We report a case of communicating accessory bile duct that was identified before elective surgery. A 58-year old female was diagnosed of gallbladder stone by ultrasonography. She hoped to undergo surgery and referred to our hospital. A communicating accessory bile (Type c, Couinaud classification) was identified by preoperative MRCP. We performed laparoscopic cholecystectomy and were able to confirm a known communicating accessory bile duct in addition to cystic duct during the surgery. MRCP was useful to identify the variation of the bile duct anatomy and lead to safe laparoscopic surgery.

A 56-year-old man who suffered from epileptic psychosis since childhood underwent hepaticojejunostomy (HJ) Roux-en-Y (RY) reconstruction for bile duct injuries (BDI) during laparoscopic cholecystectomy for cholecystolithiasis. Thereafter, he experienced recurrent cholangitis and was referred to our department for persistent biliary and ileus symptoms. Magnetic resonance cholangiopancreatography in the previous hospital revealed a possible HJ anastomotic stenosis. However, drip infusion cholangiographic-CT (DIC-CT) and percutaneous transhepatic cholangiography showed stasis of the contrast media within the dilatation of the retrocolic RY limb. Thus, open laparotomy was performed, and the bending and slackening condition of the hepatic RY limb was remodeled by dissection. His post-surgical course was uneventful, without cholangitis or ileus. Thus, we experienced a rare case of severe recurrent cholangitis after HJ for post-cholecystectomy BDI caused by improper technical construction without biliary stricture. A multidisciplinary approach including jejunography of the RY limb and cholangiography could be required for good long-term results in this application. DIC-CT was useful for evaluation of the biliary tracts and the RY limb.

A 65-year-old man was referred to our hospital due to elevated lesion of the gallbladder on US. CT showed that enhanced elevated lesion of the neck of the gallbladder and enhanced wall thickness of the body and fundus of the gallbladder, and direct invasion into the liver and transverse colon (cholecystocolic fistula) was suspected. Imaging revealed advanced gallbladder cancer was most likely, but xanthogranulomatous cholecystitis was not excluded. First, staging laparoscopy was performed to confirm no dissemination and liver metastases. Then, we performed cholecystectomy with partial hepatectomy, partial resection of transverse colon and abdominal wall. Histopathological examination revealed a moderately differentiated tubular adenocarcinoma of the gallbladder (T3, N0, M0, stage III), and existence of cholecystocolic fistula without cancer invasion. Formation of cholecystocolic fistula might be caused by obstructive cholecystitis, not cancer invasion.

A 54-year-old female case. 10 years ago, endoscopic sphincterotomy and mechanical lithotripsy were performed on common bile duct stones associated with hereditary spherocytosis. After four years, the common bile duct stones recurred, so that endoscopic mechanical lithotripsy was performed again. Ursodeoxycholic acid was started for the purpose of suppressing recurrence of common bile duct stones. After that, since there were six recurrences of common bile duct stones in 4 years, component analysis of the removed stones resulted in ursodeoxycholic acid as the main component. There is no recurrence of bile duct stone for 1.5 years after discontinuing ursodeoxycholic acid. Bile duct stones caused by ursodeoxycholic acid were difficult to distinguish from other stones according to abdominal ultrasound and CT and macroscopic findings of stones. In cases of recurrent bile duct stones during administration of ursodeoxycholic acid, it is important to perform stone analysis in consideration of bile duct stones due to ursodeoxycholic acid.

General rules of biliary tract carcinoma (6^th edition) was revised in November, 2013 after September, 2003 (5^th edition), with reference to 2010 WHO classification of tumors of digestive system. Main changes of pathologic items in 6^th edition are as follows: i) Extrahepatic cholangiocarcinoma was divided into perihilar and distal cholangiocarcinoma. ii) Three types of preinvasive biliary tract carcinoma (biliary intraepithelial neoplasia, intraductal papillary neoplasia, and mucinous cystic neoplasm) were adopted. iii) In addition, neuroendocrine tumor of the biliary tree was similarly classified as done in the pancreas and gastroeintestinal tract. Herein, these pathological items were practically described with consideration of pathological diagnosis. Furthermore, new pathologic findings and discussions on several pathologic items in 6^th edition of general rules were described for next revision of general rules of biliary tract carcinoma.