It is very important for the Japan Pancreas Society to communicate and collaborate with international and other domestic organizations with the aim of expanding the knowledge relating to studies of pancreatic diseases. The Japan Pancreas Society has promoted international collaboration through joint meetings with the International Association of Pancreatology (IAP) and the American Pancreatic Association (APA). Publication of official journals, Suizo and Pancreas, as well as close cooperation with Pancreatology have also contributed to international communication in the community of pancreatologists. However, international communication among young investigators at the individual level is currently hampered by the pandemic of COVID-19. Taking every opportunity including joint meetings of the Japan Pancreas Society with the IAP and APA to maintain international communication, we should help the next generation of scientists and promote international collaborative studies in the future.

Current situations and problems, including a global comparison, for the pathological diagnosis of pancreatitis were discussed. The international consensus diagnostic criteria (ICDC) are used for the diagnosis of autoimmune pancreatitis (AIP). Japanese AIP clinical diagnostic criteria 2018 is also based on the ICDC, but some of the histological criteria were changed in view of the biopsy diagnosis. In order to cope with an increasing volume of pancreatic biopsies, guidance for diagnosing AIP with biopsy tissue was published in Japan. The diagnostic hallmark of type 2 AIP is the granulocytic epithelial lesion (GEL). The GEL is primarily a finding in the interlobular pancreatic ducts, but there is no consensus on whether lesions in the lobules, which are usually obtained at biopsy, can be regarded as a GEL. Guidelines for the histopathology of chronic pancreatitis established by the working group for the international consensus guidelines for chronic pancreatitis were published, and current issues in the histological diagnosis of chronic pancreatitis were stated with agreement of pathologists. Issues that remain to be solved include histological findings in early chronic pancreatitis and exclusion of asymptomatic fibrosis.

Pathological diagnoses have a great influence on decision making for improved treatment of patients with neoplastic diseases. Classifications and diagnostic criteria, including the World Health Organization (WHO) classification, Armed Forces Institute of Pathology (AFIP) classification, Union for International Cancer Control (UICC) classification and others, are based on the experience and knowledge of many of our predecessors. International Collaborations on Cancer Reporting (ICCR) and the WHO reporting system of cytopathological diagnosis serve as movements for international standardization on how to deal with pathological diagnoses and evaluation in clinical practice. This paper focuses on the process of establishing international classifications and standards for pathological diagnosis, and as a process to reach that point, the importance of international networking of individuals and related academic societies.

Guidelines for the treatment of patients with acute pancreatitis have recently been published in various countries. In this paper, we compared the recommendations and evidence ratings of eight guidelines collected based on the following, (1) published within the last 10 years (2010-2020), (2) written in English, (3) published by domestic and foreign medical associations and societies, and (4) using the GRADE system. Of 30 items in 7 major categories, 26 were in general agreement, but there was disagreement on 4 items. One of the reasons for the divergent recommendations was the lack of sufficient evidence. The evaluation of the quality of evidence was greatly divided even within items. From the above, it was thought that the level of recommendation would be unified to some extent in the future as new accurate evidence is accumulated.

This article explores the current status of internationalization of the management of patients with chronic pancreatitis in Japan. Although both the number of people who travel to Japan and the number who attend international congresses are decreasing due to the COVID-19 pandemic, the status of medical internationalization has not changed. It is important to understand the differences in many aspects including ethnic and cultural background, socioeconomic status, and dietary behavior for the optimal management of this disease. Several international consensus guidelines developed recently for the management of chronic pancreatitis have focused on reduction of risk factors for complications and their screening. We should understand these guidelines sufficiently and manage this disease appropriately. There are many important points when interacting with patients with chronic pancreatitis who are foreigners visiting Japan.

The third revision of the International Consensus Guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) of the pancreas will be discussed during the 26^th Meeting of the International Association of Pancreatology 2022 in Japan. There are 7 points to be discussed. 1) Morphological aspects; definition and significance of mixed type IPMN. 2) Subtype classification; independent of oncocytic type. 3) Pathological diagnosis; non-invasive carcinoma and high-grade dysplasia, and the definition of malignancy. 4) Modification of the algorithm for the management of branch duct IPMN. 5) Modification of the factors of high-risk stigmata and worrisome features; threshold of the height of mural nodules. 6) Modification of the surveillance protocol of branch duct IPMN considering possible development of concomitant pancreatic ductal adenocarcinoma (PDAC). 7) Surveillance protocol after resection of IPMN focusing on the remnant pancreas; possible development of concomitant PDAC after resection of non-intestinal IPMN and monoclonal skip lesions after resection of main duct IPMN.

In this article, the Clinical Practice Guidelines for Pancreatic Cancer 2019 from the Japan Pancreas Society and the NCCN guidelines version 2. 2021 are compared and a variety of differences clarified including development methods and recommendations. The evidence on which a guideline is based is generally universal, but the guideline itself can vary from country to country, because of different social environments regarding healthcare policies and systems, and because the strength of the evidence can vary depending on where the evidence originated and where the evidence is adapted to. Optimal recommendations for patients and medical practitioners in this country should be proposed.

The outcome of patients with pancreatic cancer is still poor, and there is an urgent need to improve it. Neoadjuvant chemotherapy or chemoradiation is characterized by high compliance and is becoming a regular part of the multidisciplinary treatment for pancreatic cancer. In Japan, Europe, and the United States, neoadjuvant therapy for patients with resectable and borderline resectable pancreatic cancer and conversion surgery for unresectable pancreatic cancer are becoming widely used. In recent years, evidence supporting the use of neoadjuvant therapy in patients with pancreatic cancer has been generated from many institutions. In particular, the Prep02/JSAP05 trial was the first to demonstrate the efficacy of neoadjuvant therapy for patients with resectable pancreatic cancer. However, the outcomes of patients with pancreatic cancer are still not satisfactory. Clinical research to improve therapeutic regimens and search for useful biomarkers to determine the indications for surgery will continue.

A 46-year-old man underwent high anterior resection and splenectomy for rectal cancer and idiopathic thrombocytopenic purpura, respectively. However, a postoperative pancreatic fistula developed. Although the patient's condition improved with pancreatic duct stenting, recurrence of the pancreatic fistula and intra-abdominal abscesses were later noted. Conventional treatment was expected to be refractory, considering the endoscopic retrograde pancreatography findings and coil embolization was performed, with placement of a transpapillary pancreatic duct stent. Furthermore, percutaneous infusions of n-butyl-cyanoacrylate were administered, and was applied to sandwich the pancreatic fistula upstream and downstream. Pancreatitis was observed afterward and was relieved with non-operative management. The rectal cancer subsequently recurred, and recurrence of the pancreatic fistula was suspected, necessitating operative intervention. We report that these procedures may be adopted as treatment for refractory pancreatic fistulas.

A 79 year old male was evaluated for a pancreatic tumor found at screening and was referred for further evaluation. Blood tests showed an elevated gastrin level, but tumor markers were within normal limits. Computed tomography scan of the abdomen showed an 8mm tumor in the pancreatic body in the early phase. The tumor was the same radiodensity as the artery, and had grown over 4 years. An aneurysm was suspected and abdominal angiography was performed. The tumor was not an aneurysm and was suspected to be a nodular hypervascular tumor. Endoscopic ultrasound showed similar findings, and although biopsy was considered, it was not performed because of the possibility of bleeding. Distal pancreatectomy was performed for the purpose of diagnosis and treatment. In the tumor, vascular endothelial-like cells without atypia proliferated forming a large vascular cavity, and was diagnosed as a pancreatic cavernous hemangioma considering the immunohistochemistry findings. Pancreatic hemangiomas are rare and the present patient is reviewed with cases reported in Japan.

A 77-year-old man with chronic alcoholic pancreatitis presented with abdominal pain. Computed tomography scan revealed a stone in the pancreatic head with a subhepatic fluid collection. Endoscopic retrograde pancreatography was performed for drainage of the main pancreatic duct (MPD); however, the guidewire and catheter could not pass beyond the pancreatic stone. Endoscopic ultrasonographically guided pancreatic duct drainage (EUS-PD) was performed, and a plastic stent was placed in the MPD and the stomach. Extracorporeal shock wave lithotripsy (ESWL) was performed 10 days after EUS-PD. The pancreatic stone disappeared after ESWL. Two months later, the plastic stent was removed, and endoscopic pancreatic sphincterotomy was performed using the EUS-PD rendezvous method. No recurrent pancreatic stones or obstructive pancreatitis was observed during more than 1-year follow-up. ESWL after EUS-PD may be feasible for the removal of therapeutically challenging trans-papillary pancreatic stones.