Discrimination between sclerosing cholangitis-associated autoimmune pancreatitis and primary sclerosing cholangitis, cancer using intraductal ultrasonography

The Role of Endoscopic Ultrasound and Ancillary Techniques in the Diagnosis of Autoimmune Pancreatitis: A Comprehensive Review

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis with a multifactorial pathogenesis. Historically, it has been classified as type 1 and type 2, according to its clinical and histological features. The diagnosis of AIP is challenging and relies on a combination of clinical, histopathologic, serologic, and imaging characteristics. In the available guidelines, the imaging hallmarks of AIP are based on cross-sectional imaging and cholangiopancreatography retrograde endoscopic findings. Endoscopic ultrasound (EUS) is generally used for pancreatic tissue acquisition to rule out pancreatic cancer and diagnose AIP with limited accuracy. Several papers reported the reliability of EUS for providing informative morphologic features of AIP. Nowadays, the improvement in the resolution of EUS conventional images and the development of new ancillary technologies have further increased the diagnostic yield of EUS: contrast-enhanced EUS and EUS elastography are non-invasive and real-time techniques that strongly support the diagnosis and management of pancreatic diseases. In this review article, we will present the role of conventional EUS and ancillary diagnostic techniques in the diagnosis of AIP to support clinicians and endosonographers in managing this condition.

Secondary sclerosing cholangitis and IgG4-sclerosing cholangitis - A review of cholangiographic and ultrasound imaging

Sclerosing cholangitis (SC) represents a spectrum of chronic progressive cholestatic diseases of the intrahepatic and/or extrahepatic biliary system characterized by patchy inflammation, fibrosis, and stricturing. Primary and secondary SC must be distinguished given the different treatment modalities, risks of malignancy, and progression to portal hypertension, cirrhosis, and hepatic failure. This review focuses on secondary SC and the pathogenic mechanisms, risk factors, clinical presentation, and novel imaging modalities that help to distinguish between these conditions. We explore the detailed use of cholangiography and ultrasound imaging techniques.

Amendment of the Japanese consensus guidelines for autoimmune pancreatitis, 2020

In response to the latest knowledge and the amendment of the Japanese diagnostic criteria for autoimmune pancreatitis (AIP) in 2018, the Japanese consensus guidelines for managing AIP in 2013 were required to be revised. Three committees [the professional committee for developing clinical questions (CQs) and statements by Japanese specialists; the expert panelist committee for rating statements by the modified Delphi method; and the evaluating committee of moderators] were organized. Twenty specialists in AIP extracted the specific clinical statements from a total of 5218 articles (1963-2019) from a search in PubMed and the Cochrane Library. The professional committee made 14, 9, 5, and 11 CQs and statements for the current concept and diagnosis, extra-pancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded the statements as valid after a two-round modified Delphi approach with individually rating these clinical statements, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid. After evaluation by the moderators, the amendment of the Japanese consensus guidelines for AIP has been proposed in 2020.

Novel biliopancreatic duct endoscope combining optical coherence tomography with intraductal US for exploring the bile duct: a diagnostic study in a porcine model

BACKGROUND AND AIMS

Existing biliopancreatic duct endoscopy is deficient in the examination of early biliary and pancreatic tumors. This study aimed to evaluate the usefulness and feasibility of a novel ultrafine, separable, biliopancreatic duct endoscopy device with dual modalities of intraductal US (IDUS) and optical coherence tomography (OCT) for the in vivo assessment of the biliopancreatic duct system during ERCP.

METHODS

Five Bama miniature pigs were selected to probe their common bile duct and branches by using this novel equipment during ERCP. The feasibility of the procedure was evaluated by clear, clinically interpretable images obtained by using spiral scanning with the pull-back method. The clinical usefulness of the novel product was evaluated by postoperative choledochoscopy and assessment of the animal's general condition.

RESULTS

One hundred forty-one pairs of images from 5 Bama miniature pigs were acquired. Visualization of the bile duct using both OCT and IDUS was characterized by a differentiated 3-layer architecture, whereas IDUS had poor clarity when compared with OCT. Postoperative choledochoscopy showed no local lesion in the bile duct wall, and the general condition of animals was normal.

CONCLUSIONS

This prospective evaluation indicated the feasibility and potential clinical value of the novel, ultrafine, separable biliopancreatic duct endoscopy device. The fusion of the 2 imaging modalities can shed light on the early diagnosis of biliary and pancreatic tumors. Further studies will be carried out to establish diagnosis criteria with the dual-modality imaging using an animal pathologic model and a human clinical study.

Classification and Diagnostic Criteria for IgG4-Related Sclerosing Cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) can be classified into four types based on cholangiographic findings and regions of biliary stricture. This cholangiographic classification is useful to differentiate IgG4-SC from mimickers including cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Autoimmune pancreatitis (AIP) is a valuable clue for the diagnosis of IgG4-SC because the two are frequently found in association with each other. Two sets of diagnostic criteria for IgG4-SC have been proposed. In Japan, the clinical diagnostic criteria 2020 were recently developed. These clinical diagnostic criteria include narrowing of the intrahepatic and/or extrahepatic bile duct, thickening of the bile duct wall, serological findings, pathological findings, other organ involvement, and effectiveness of steroid therapy. When these criteria are applied, IgG4-SC is initially classified as associated or not associated with AIP, and cholangiographic classification is used for differential diagnosis. In most instances, IgG4-SC can be diagnosed on the basis of clinical diagnostic criteria. However, it is challenging to diagnose isolated IgG4-SC or IgG4-SC not associated with AIP. Here, we review the classification and diagnostic criteria for IgG4-SC, specifically focusing on the clinical diagnostic criteria 2020 and a large IgG4-SC case series from a nationwide survey in Japan.

Endoscopic retrograde cholangiopancreatography and intraductal ultrasonography in the diagnosis of autoimmune pancreatitis and IgG4-related sclerosing cholangitis

Endoscopic retrograde cholangiopancreatography is used to evaluate the narrowing of the main pancreatic duct in autoimmune pancreatitis (AIP) and biliary stricture in IgG4-related sclerosing cholangitis (IgG4-SC). Intraductal ultrasonography enables detailed visualization of the thickening of the bile duct wall in IgG4-SC. Pancreatic cancer, cholangiocarcinoma, and primary sclerosing cholangitis are important mimicking conditions of AIP and IgG4-SC. Diffuse or segmental stricture without marked upstream dilatation is a typical pancreatographic finding in AIP. By contrast, a single, short stricture with marked upstream dilatation is a typical finding in pancreatic cancer. The cholangiogram of IgG4-SC is classified into four types based on biliary stricture location, and this cholangiogram classification is useful for the differential diagnosis of IgG4-SC. Endoscopic retrograde cholangiography can be used to distinguish between IgG4-SC and primary sclerosing cholangitis. A segmental/long and intrapancreatic stricture is a characteristic finding of IgG4-SC, whereas band-like strictures, a beaded or pruned-tree appearance, and diverticulum-like outpouching are characteristic of primary sclerosing cholangitis. The characteristic intraductal ultrasonographic findings of circular-symmetrical wall thickening, smooth outer and inner margins, and homogeneous internal echo at the biliary stricture site are useful for diagnosis of IgG4-SC. Thickening of the bile duct wall at non-stricture sites is also a typical intraductal ultrasonographic finding of IgG4-SC and can be used for differential diagnosis from cholangiocarcinoma. Transpapillary bile duct and duodenal papilla biopsy during endoscopic retrograde cholangiopancreatography are also useful in the diagnosis of IgG4-SC.

Clinical features of isolated proximal-type immunoglobulin G4-related sclerosing cholangitis

BACKGROUND AND AIM

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) presents as isolated proximal-type sclerosing cholangitis (i-SC). The present study sought to clarify the imaging differences between i-SC and Klatskin tumor. Differences between i-SC and IgG4-SC associated with autoimmune pancreatitis (AIP-SC) were also studied.

METHODS

Differentiating factors between i-SC and Klatskin tumor were studied. Serum IgG4 level, CA19-9 level, computed tomography (CT) findings, cholangiography findings (symmetrical smooth long stricture extending into the upper bile duct [SSLS]), endosonographic features (continuous symmetrical mucosal lesion to the hilar part [CSML]), endoscopic biopsy results, treatment, relapse, and survival were also compared between patients with i-SC and those with AIP-SC.

RESULTS

For a differential diagnosis between i-SC (N = 9) and Klatskin tumor (N = 47), the cut-off value of serum IgG4 level was 150 mg/dL (sensitivity, 0.857, specificity, 0.966). Logistic regression analysis indicated that serum IgG4 level, presence of SSLS, presence of CSML, and presence of swollen ampulla are independent factor for identifying i-SC. Relapse rate was significantly higher in the IgG4-SC with AIP group than in the i-SC group (log rank, P = 0.046).

CONCLUSION

Isolated proximal-type sclerosing cholangitis presents as a nodular lesion with SSLS and/or CSML mimicking a Klatskin tumor. Those endoscopic features might provide a diagnostic clue for i-SC. i-SC is likely to have a more favorable prognosis than IgG4-SC with AIP.

Clinical practice guidelines for IgG4-related sclerosing cholangitis

IgG4‐related sclerosing cholangitis (IgG4‐SC) is a distinct type of cholangitis frequently associated with autoimmune pancreatitis and currently recognized as a biliary manifestation of IgG4‐related disease. Although clinical diagnostic criteria of IgG4‐SC were established in 2012, differential diagnosis from primary sclerosing cholangitis and cholangiocarcinoma is sometimes difficult. Furthermore, no practical guidelines for IgG4‐SC are available. Because the evidence level of most articles retrieved through searching the PubMed, Cochrane Library, and Igaku Chuo Zasshi databases was below C based on the systematic review evaluation system of clinical practice guidelines MINDS 2014, we developed consensus guidelines using the modified Delphi approach. Three committees (a guideline creating committee, an expert panelist committee for rating statements according to the modified Delphi method, and an evaluating committee) were organized. Eighteen clinical questions (CQs) with clinical statements were developed regarding diagnosis (14 CQs) and treatment (4 CQs). Recommendation levels for clinical statements were set using the modified Delphi approach. The guidelines explain methods for accurate diagnosis, and safe and appropriate treatment of IgG4‐SC.

Clinical guidelines for primary sclerosing cholangitis 2017

BACKGROUND

Primary sclerosing cholangitis (PSC) is relatively rare disease and pathogenesis and methods of treatments were still not established. Then, we had conducted the making clinical guidelines to manage patients with PSC based on the literature review and expert opinions. These clinical guidelines were made for the medical doctors on the management of PSC, except child case of PSC.

METHODS

We had employed modified Delphi method. The production committee decided guidelines, strength of recommendations and evidence level after reviewed literatures systematically, and The Expert panel evaluated those. The Scientific Committee of the Japan Biliary Association (JBA) evaluated revised guidelines, and the Public comments were collected on web site of JBA.

RESULTS

We had made 16 guidelines about epidemiology/pathophysiology, diagnostics, therapy and prognosis. Also, we had made both diagnostic and therapeutic flow chart.

CONCLUSIONS

We hope that these guidelines will contribute to the improvement and development of the medical care of PSC.

Cholangitis: Diagnosis, Treatment and Prognosis

Cholangitis is a serious life-threatening situation affecting the hepatobiliary system. This review provides an update regarding the clinical and pathological features of various forms of cholangitis. A comprehensive search was performed in the PubMed, Scopus, and Web of Knowledge databases. It was found that the etiology and pathogenesis of cholangitis are heterogeneous. Cholangitis can be categorized as primary sclerosing (PSC), secondary (acute) cholangitis, and a recently characterized form, known as IgG4-associated cholangitis (IAC). Roles of genetic and acquired factors have been noted in development of various forms of cholangitis. PSC commonly follows a chronic and progressive course that may terminate in hepatobiliary neoplasms. In particular, PSC commonly has been associated with inflammatory bowel disease. Bacterial infections are known as the most common cause for AC. On the other hand, IAC has been commonly encountered along with pancreatitis. Imaging evaluation of the hepatobiliary system has emerged as a crucial tool in the management of cholangitis. Endoscopic retrograde cholangiography, magnetic resonance cholangiopancreatography and endoscopic ultrasonography comprise three of the modalities that are frequently exploited as both diagnostic and therapeutic tools. Biliary drainage procedures using these methods is necessary for controlling the progression of cholangitis. Promising results have been reported for the role of antibiotic treatment in management of AC and PSC; however, immunosuppressive drugs have also rendered clinical responses in IAC. With respect to the high rate of complications, surgical interventions in patients with cholangitis are generally restricted to those patients in whom other therapeutic approaches have failed.

The 2016 diagnostic criteria for primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown cause that is characterized pathologically by an inflammatory and fibrotic process centered on the epithelium, leading to diffuse biliary stenosis and increased wall thickness throughout the intra- and extra-hepatic biliary trees. A nationwide survey in Japan revealed several differences in the clinical aspects of PSC between Japan and Western countries. PSC was recently designated an intractable hepatobiliary disease in Japan. The aim of this study was to establish Japanese diagnostic criteria for PSC according to the current Japanese conditions.

METHODS

The Intractable Hepato-Biliary Diseases Study Group in Japan of the Committee of Research on Measures for Intractable Diseases established a working group consisting of researchers specializing in PSC and proposed the 2016 Japanese diagnostic criteria for PSC.

RESULTS

The diagnostic criteria consisted of the major and minor items. Major items are directly related to bile duct changes based on biliary tract imaging and an increased alkaline phosphatase level. Minor items consist of an association with inflammatory bowel disease and liver histology.

CONCLUSION

The diagnostic criteria for PSC are useful for general physicians in practice.

Recent advances in research of immunoglobulin G4-related autoimmune pancreatits

Autoimmune pancreatitis (AIP) is a rare type of chronic pancreatitis that belongs to the spectrum of immunoglobulin G4 (IgG4) related diseases. AIP is characterized by lymphoplasmacytic infiltration, storiform fibrosis, obliterative phlebitis, and increased IgG4+ plasma cells. Patients with AIP present clinically with recurrent pancreatitis and obstructive jaundice, symptoms involving bile ducts and salivary glands and so on. Serum IgG4 level is often elevated. The main imaging manifestation of AIP is a "sausage-shaped pancreas" and multiple strictures of the main pancreatic duct. AIP responds sensitively to glucocorticosteroids but relapses easily. In relapsed cases, re-administration of glucocorticosteroids alone or in combination with immune modulators is effective.

The role of intraductal ultrasonography in pancreatobiliary diseases

Intraductal ultrasonography (IDUS) provides real-time, cross-sectional imaging of pancreatobiliary ducts and surrounding structures during endoscopic retrograde cholangiopancreatography using a high-frequency ultrasound (US) transducer. Hence, IDUS has been considered a sensitive tool in the evaluation of suspicious choledocholithiasis and neoplasms, to help distinguish between benign and malignant bile duct strictures or wall thickness, and to assess tumor extension and invasion depth. With the rapid development and enriched choices of sensitive diagnostic modalities include but are not limited to endoscopic US, peroral cholangioscopy, and confocal laser endomicroscopy, it is needed to systematically assess the role of IDUS in the investigation of pancreatobiliary diseases. Some new developments and innovative use of IDUS techniques will be discussed in this paper with the review of literature.

Comparison of intraductal ultrasonography findings between primary sclerosing cholangitis and IgG4-related sclerosing cholangitis

BACKGROUND AND AIM

Comparisons of intraductal ultrasonography (IDUS) findings between primary sclerosing cholangitis (PSC) and IgG4-related sclerosing cholangitis (IgG4-SC) have not been elucidated. We aimed to clarify the differences in transpapillary IDUS findings between PSC and IgG4-SC.

METHODS

We retrospectively compared transpapillary IDUS findings between 15 patients with PSC and 35 patients with IgG4-SC between 2004 and 2014.

RESULTS

IDUS findings of circular-asymmetric wall thickness, irregular inner margin, diverticulum-like outpouching, unclear outer margin, heterogeneous internal echo, and disappearance of three layers were significantly higher in PSC than in IgG4-SC (P < 0.001). Irregular inner margin, diverticulum-like outpouching, and disappearance of three layers were specific IDUS findings for PSC compared to IgG4-SC. Diverticulum-like outpouching on IDUS and endoscopic retrograde cholangiogram (ERC) was observed in 10 (67%) and five (33%) of 15 patients with PSC, respectively. However, based on IDUS and ERC, diverticulum-like outpouching was not observed in any patient with IgG4-SC. All five patients with diverticulum-like outpouching on ERC had diverticulum-like outpouching on IDUS, and five (50%) of 10 patients without diverticulum-like outpouching on ERC had diverticulum-like outpouching on IDUS.

CONCLUSIONS

The IDUS findings differed between PSC and IgG4-SC. Irregular inner margin, diverticulum-like outpouching, and disappearance of three layers are specific IDUS findings for PSC compared to IgG4-SC. IDUS is a more useful procedure than ERC for the early detection of diverticulum-like outpouching.

Advances in research of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic autoimmune liver disease characterized by diffuse inflammation, concentric fibrosis, focal or segmental stricture of intrahepatic and/or extrahepatic bile ducts, which can eventually lead to cirrhosis or hepatic function failure. The pathogenesis of PSC may involve genetic susceptibility, innate or adaptive immunity, and Epstein-Barr virus infection. Diagnostic imaging modalities include endoscopic retrograde cholangiography, magnetic resonance cholangiopancreatography, and high-resolution three-dimensional SPGR. Proteomic analysis of bile and urine may become a new tool for early diagnosis of cholangiocarcinoma in PSC patients. Ursodeoxycholic acid (UDCA), endoscopic therapy and liver transplantation are major treatments for PSC.