Percutaneous gallbladder drainage is performed in patients with acute cholecystitis who are not eligible for emergency surgery and are scheduled for standby surgery. However, endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) is expected to be an alternative method, but it is mainly used in nonresectable cases. In this study, we performed laparoscopic cholecystectomy in five living pigs after EUS-GBD using a newly developed device based on the hypothesis that transgastric drainage would enable laparoscopic cholecystectomy. In all cases, cholecystectomy could be performed without laparotomy. In the future, we would like to verify the feasibility and safety of laparoscopic cholecystectomy after EUS-GBD using this device in humans.

Clinicians should reduce unnecessary radiation exposure when there is no gaze at the fluoroscopy monitor. We have developed a new eye-tracking fluoroscopy system that informs the radiologic technologist when the operators' line of sight is directed toward the monitor. The aim of this study was to evaluate the effectiveness of the system. This was a retrospective, single-center study comprising 15 endoscopic procedures. Median X-ray exposure was 277.4 seconds in the use group and 366.5 seconds in the non-use group (p=0.61). The number of unnecessary radiation exposure was 0 (interquartile range: 0-1.5) vs. 6 (4-10), p=0. 013. Unnecessary radiation exposure rate was significantly lower in the use group than in the non-use group (2.3% vs. 33.3%, p=0.017). In the non-use group, unnecessary exposure rate increased due to non-detection of line-of-sight to the fluoroscopy monitor intervening between detections during X-ray exposure. Appropriate X-ray inactivation using the eye-tracking fluoroscopy system led to increase the number of X-ray activation and to reduce the unnecessary radiation exposure time.

Anatomical variations in the hepatic artery are frequently encountered in pancreatoduodenectomy (PD). These variations include an aberrant hepatic artery (AHA), which was found in 35% of cases in a study of 172 patients who underwent PD. Within this group, 2.3% of patients had a specific type of AHA, called the aberrant right hepatic artery (ARHA), which arises from the gastroduodenal artery (GDA). This type of AHA is particularly challenging to deal with during PD because it can be accidentally damaged when the GDA is ligated. Previous reports have shown the incidence of this variation to be 0.28% to 2.0%. To prevent complications during PD, such as liver abscess, bile duct stenosis, and bilioenteric anastomotic leakage, it is critical to preserve the AHA. To achieve this, preoperative imaging techniques, such as enhance-contrasted CT with three-dimensional reconstruction, can help identify the relationship between the tumor and HA anatomy. Additionally, an intraoperative clamp test of GDA before resection may be useful in preventing ARHA injury.

Despite recent advances in imaging technology with a steadily improved evaluation of localization and the extension of biliary tract cancer, pathological assessment based on tissue sampling is essential for a definitive diagnosis and accurate evaluation of the progression. Furthermore, in the coming era of genomic medicine, high-quality tissue samples from individual patients suitable for comprehensive genomic profiling tests is required to provide personalized medicine based on patients' own genetic information. However, there are various challenges in tissue collection from bile ducts using existing methods. Here, we refer to points to be considered in the preoperative diagnosis of biliary tract cancer, and review the current status of tissue sampling for pathological evaluation by bile duct stricture biopsy and mapping biopsy using existing methods. In addition, we will discuss the features, results to date, and future prospects of the new device, which was developed to overcome various challenges in the diagnosis of biliary tract cancer.

A 72-year-old man was admitted to our hospital with a diagnosis of septic shock due to acute cholangitis. Computed tomography (CT) suggested cholangitis due to a calculus measuring 20mm lodged at the height of the confluence of the cystic, common hepatic, and common bile ducts. Based on ERCP, MRCP, and DIC-CT findings, Mirizzi syndrome with common hepato-cholecystic fistula was suspected. An ERBD tube was placed in B2, and the cholangitis was relieved with antibiotics and vasopressors. The patient had undergone conservative treatment for cholangitis due to common bile duct stones 8 years prior, and ERCP at the time showed an exceptional aberrant B6, but the MRCP and DIC-CT in this round of treatment did not reveal the B6 branch, suggesting that this site may also be involved in the fistula. Based on the above findings, we decided to perform an open partial cholecystectomy to securely preserve the B6. The postoperative course was uneventful with no stenosis in the bile duct.

A 65-year-old woman was referred to our hospital for the treatment of obstructive jaundice. She had received chemotherapy under the diagnosis of gallbladder cancer and multiple lymph node metastasis. She had an oval-shaped tumor with contrast effect in the gallbladder body and enlargement of porta hepatis and paraaortic lymph nodes on contrast-enhanced CT scan. The lesions revealed decreased diffusivity on diffusion weighted images of MRI. After EUS-guided biliary drainage, EUS-guided fine needle aspiration (EUS-FNA) was performed for a peripancreatic lymph node and immunohistology examinations showed neuroendocrine carcinoma (NEC). The patient had combined chemotherapy of carboplatin and etoposide, which resulted in progressive disease during the second course. Percutaneous biopsy from the liver invaded by gallbladder tumor revealed similar pathological findings to that acquired with EUS-FNA. Although the therapeutic effect on this patient was limited, EUS-FNA may give a correct therapeutic strategy for even rare diseases.

A 73-year-old male was transferred to our hospital because of elevated serum hepatobiliary enzymes. Radiological studies showed polypoid tumor in the distal bile duct, for which malignancy could not be denied. Pancreatoduodenectomy specimen showed a 30mm-sized, friable and polypoid tumor at the distal bile duct. Histologically, tumor comprised of spindle to round mononuclear tumor cells with abundant osteoclast-like giant cells. Immunohistochemical study showed positivity for SMA and Vimentin/negativity for desmin, CD34, Histone3.3G34W and ALK. The labeling index of Ki-67 was 5-30%. At the tumor base, biliary intraepithelial neoplasia (BilIN) was seen without invasive adenocarcinoma component. Molecular study showed the tumor lacked MYHii USP6 fusion, which is often seen in nodular fasciitis. Polypoid tumor was KRAS: mutated, while BilIN component was KRAS: wild. Pathological diagnosis of anaplastic carcinoma with osteoclast-like giant cells (AC with OC) was finally made. Due to the lack of nuclear atypia and invasive adenocarcinoma component, authors felt the pathological diagnosis for the present case was very difficult. AC with OC of the bile duct is very rare, and, so far, its prognosis and details are unknown. Studies with more cases are necessary.

A 73-year-old woman presented to our hospital with bile leakage after laparoscopic cholecystectomy. Preoperative imaging studies had revealed the right anterior and posterior bile ducts joined separately to the neck of the gallbladder, an extremely rare variant of the biliary duct, known as cholecystohepatic duct. An intraoperative video revealed that the right anterior and posterior bile ducts were divided separately during surgery. Biliary reconstruction using bilioenteric reconstruction was considered difficult due to abscess formation; hence, we performed right hemihepatectomy after percutaneous intraabdominal abscess drainage.

To prevent intraoperative biliary injury, careful preoperative imaging evaluation of the biliary tract anatomy and operative planning is critical for patients with cholecystohepatic duct.

A 70-year-old man presented with bile duct dilatation on serial follow-up plain CT scans four years after a distal gastrectomy for gastric cancer. Contrast-enhanced CT showed swelling of the ampulla of Vater (AV) and dilatation of the common bile duct with enhancement of the thickened wall. Intraductal ultrasound showed circumferential wall thickening in continuity from the intrapapillary bile duct (Ab) to the distal bile duct (Bd). The brushing cytology obtained from the Ab and terminal Bd revealed class V, suggesting adenocarcinoma. The patient underwent pancreatoduodenectomy because of suspected carcinoma of the AV extending to Bd. A pathological examination showed flat intraepithelial carcinoma (FIC) of the AV superficially extending to both the Bd and origin part of the main pancreatic duct. The lamina propria of the Ab and intrapapillary pancreatic duct was thick with chronic duodenal papillitis.

The detection of FIC without invasive carcinoma on imaging is challenging. This is a clinically significant case where biliary-imaging changes reflecting the associated chronic duodenal papillitis provided the opportunity to diagnose ampullary FIC.

Immune checkpoint inhibitors (ICIs) are now the mainstay of cancer treatment, and management of immune-related adverse events (irAE) caused by ICIs is an essential skill.

Since our first report in 2017 of cholangitis after ICI treatment characterized by 1) unobstructed extrahepatic bile duct dilation, 2) diffuse extrahepatic bile duct wall thickening, 3) liver damage with predominance of biliary enzymes, 4) normal or low levels of antinuclear and antimitochondrial antibodies and IgG4, and 5) infiltration of CD8 positive T cells in the bile duct, a series of case reports of irAE cholangitis have appeared. However, the actual frequency of occurrence of cholangitis is relatively rare (0.05-0.7%). Thus no established diagnostic or therapeutic methods for this disease have established so far, making it a clinical problem. In this article, we review the concept of irAE cholangitis, diagnosis and treatment based on current knowledge, and discuss issues that need to be resolved in the future.