Autoimmune pancreatitis: an update

Potential relationship between Helicobacter pylori infection and autoimmune disorders: A narrative review

Helicobacter pylori (H. pylori) is a spiral-shaped, gram-negative, flagellated bacteria that causes gastritis symptoms. This bacterium, particularly in individuals with a genetic predisposition, has been implicated in the pathogenesis of several autoimmune diseases (AD) through complex mechanisms involving the interaction of cellular and humoral immune responses. This review article tells you about the link between H. pylori infection and several types of AD, including systemic lupus erythematosus (SLE), autoimmune pancreatitis (AIP), rheumatoid arthritis (RA), Sjögren syndrome (SjS), psoriasis, and antiphospholipid syndrome (APS). We conducted a comprehensive analysis of the current literature to elucidate the potential role of H. pylori as a triggering factor for these disorders. Our findings suggest a significant correlation between H. pylori infection and the onset or exacerbation of specific ADs. This relationship is common mechanisms, including molecular mimicry, chronic inflammation, epitope spreading, and cytokine dysregulation. While H. pylori is implicated in AD, other factors such as genetic predisposition, environmental triggers, and other microbial agents also play crucial roles. Other pathogens, such as Epstein-Barr virus (EBV), cytomegalovirus (CMV), and bacteria like Mycobacterium tuberculosis and Chlamydia pneumoniae have been linked to ADs. These shared pathways highlight the potential role of H. pylori as a unifying factor in the pathogenesis of diverse ADs. Further research is necessary to fully understand the interactions between H. pylori and the immune system in the context of autoimmunity. This review aims to provide a detailed overview of the knowledge on this topic, highlighting the need for additional studies to clarify these complex relationships.

Autoimmune Pancreatitis: A Review

Autoimmune pancreatitis is a rare condition of pancreatic inflammation with two classic subtypes. The emergence of a third subtype, ICI-induced pancreatitis, highlights the need for knowledge of each type to ensure accurate diagnosis and treatment. Abbreviations: AIP-Autoimmune pancreatitis; AIP-1-Type 1 autoimmune pancreatitis, also known as lymphoplasmacytic sclerosing pancreatitis (LPSP); AIP-2-Type 2 autoimmune pancreatitis, also referred to as idiopathic duct-centric pancreatitis (IDCP); AIP-3-Type 3 autoimmune pancreatitis, also known as immune checkpoint inhibitor (ICI)-induced autoimmune pancreatitis; IgG4-RD-Immunoglobulin G4-related disease.

Abdominal Inflammatory Lesions Mimicking Malignancy: Imaging Pitfalls and Clues

Abdominal inflammatory lesions may closely mimic malignancies on imaging, leading to diagnostic uncertainty and potentially unnecessary interventions. This pictorial review presents a series of cases involving diverse inflammatory conditions-including autoimmune pancreatitis, xanthogranulomatous cholecystitis, diverticulitis, peritoneal tuberculosis, and others-that radiologically resembled neoplastic processes. Key imaging findings, such as mass-forming patterns, enhancement characteristics, and diffusion restriction, are discussed alongside clinical and laboratory correlations. Recognizing these mimickers is essential, as accurate diagnosis often depends on a multidisciplinary approach that integrates imaging expertise with clinical context, ultimately improving patient care and avoiding misdiagnosis.

Pancreatitis-related benign biliary strictures: a review of imaging findings and evolving endoscopic management

Biliary strictures can be secondary to a gamut of etiologies, most of which are malignant and the remaining related to a host of benign causes, including pancreatitis. Pancreatitis related benign biliary strictures (BBS) primarily involve the distal common bile duct (CBD) and can be seen in acute and chronic pancreatitis as well as their other forms, including necrotizing, groove, and autoimmune pancreatitis. Patients with pancreatitis related BBS present along a wide clinical spectrum that spans from an asymptomatic state to biliary obstruction, which not uncommonly facilitates additional workup for malignancy and endoscopic evaluation and treatment. Furthermore, the location and appearance of these strictures lends itself to various imitating benign and malignant etiologies. In this article, we will discuss the pathophysiology and clinicoradiologic features of pancreatitis related BBS while providing a review of an approach to their management focusing on endoscopic techniques.

Differentiation of Autoimmune Pancreatitis From Pancreatic Ductal Adenocarcinoma by Diffusion-Weighted Magnetic Resonance Imaging With Weighted Diffusion Subtraction

Purpose Weighted diffusion subtraction (WDS) is a new imaging technique derived from a pair of diffusion-weighted images (DWIs) using low and high b values. This study assesses the diagnostic performance of WDS in distinguishing pancreatic ductal adenocarcinoma (PDAC) from autoimmune pancreatitis (AIP) by comparing the efficacy of DWI alone compared to DWI with WDS. Methods The patient cohort consisted of 10 patients diagnosed with AIP and 28 patients diagnosed with PDAC. Two blinded radiologists reviewed the MRI images and assessed their diagnostic accuracy and confidence levels. Differences between groups A (DWI alone) and B (DWI added WDS) were assessed, and a receiver operating characteristic (ROC) curve analysis was performed. Inter-reader agreement was analyzed using weighted κ statistics, and apparent diffusion coefficient (ADC) values were calculated for both AIP and PDAC. Results In diagnostic accuracy, Group B demonstrated significantly higher area under the curve (AUC) values than Group A for both readers. The inter-reader agreement was evaluated as "substantial" in both groups. The mean confidence scores for Group B were significantly higher than those for Group A for both readers. Conclusion The addition of WDS to DWI may enhance the visual differentiation between AIP and PDAC, potentially improving diagnostic accuracy and confidence.

Treatment Strategies for Chronic Pancreatitis (CP)

Chronic pancreatitis (CP) and autoimmune pancreatitis (AIP) are diseases with overlapping features, both requiring complex management strategies. CP is characterized by pancreatic exocrine insufficiency (PEI) and pain, with treatment focused on symptom relief through pancreatic enzyme replacement therapy (PERT), pain control, and lifestyle and nutritional changes. However, the standard therapy does not address the underlying inflammation or fibrosis, which drives disease progression. AIP, on the other hand, presents with obstructive jaundice and fibrosis and is classified into two subtypes: Type 1 (AIP-1), linked to IgG4-related disease, and Type 2 (AIP-2), associated with inflammatory bowel disease. Treatment for AIP typically involves oral steroids. Immunomodulators and rituximab are used for recurrent or refractory cases. Novel therapies targeting the inflammation and fibrotic components of CP are being explored. A multidisciplinary approach is essential to optimize care and improve patients' outcomes.

The role of gut microbiome and its metabolites in pancreatitis

Gut microbiome plays a vital role in the intestinal ecosystem and has close association with metabolites. Due to the development of metabolomics and microbiomics, recent studies have observed that alteration of either the gut microbiome or metabolites may have effects on the progression of pancreatitis. Several new treatments based on the gut microbiome or metabolites have been studied extensively in recent years. Gut microbes, such as Bifidobacterium, Akkermansia, and Lactobacillus, and metabolites, such as short-chain fatty acids, bile acids, vitamin, hydrogen sulfide, and alcohol, have different effects on pancreatitis. Some preliminary studies about new intervention measures were based on the gut microbiome and metabolites such as diet, prebiotic, herbal medicine, and fecal microbiota transplantation. This review aims to summarize the recent advances about the gut microbiome, metabolites, and pancreatitis in order to determine the potential beneficial role of the gut microbiome and metabolites in pancreatitis.

Focal Autoimmune Pancreatitis Morphologically Mimicking Pancreatic Cancer: A Case Report and Literature Review

BACKGROUND Autoimmune pancreatitis (AIP) is identified as an outlier in the clinical practice of chronic pancreatitis caused by autoimmune system dysfunction. AIP is classified into 3 subtypes: AIP type 1 and AIP type 2, which are both sensitive to corticosteroids, and the recently introduced AIP type 3. CASE REPORT We present a case of a patient who presented with painless obstructive jaundice. Computed tomography (CT) revealed hyperdense gallbladder material, further dilatation of intrahepatic bile ducts, and distention of the bile duct (15 mm). Based on the available clinical data, which were strongly compatible with pancreatic cancer, Whipple surgery was selected as the treatment for this case. The consequent histopathological report revealed areas of pancreatic parenchyma with fibrous connective tissue development and dense inflammatory cell infiltration with lymphocytes and plasmacytes, which showcased IgG4 positivity. The clinical results suggested a diagnosis of AIP type 1, and the patient was referred to his treating physician for further treatment of AIP. Preoperative histological examination of the pancreas, along with evaluation of the radiological and serological features, could have aided in determining the diagnosis of AIP type 1 pancreatitis despite the unique abnormality of this particular case. CONCLUSIONS Given the aforementioned conditions, AIP, even as a rare clinical entity, emerges as a canonical ailment and should be considered a viable possibility in clinical practice since it can exclude the patient from an unnecessary surgery.

Non-O1, Non-O139 Vibrio cholerae Bacteremia in an Autoimmune Pancreatitis Patient

Over 200 different serogroups of Vibrio cholerae based on O-polysaccharide specificity have been described worldwide, including the two most important serogroups, O1 and O139. Non-O1/non-O139 V. cholerae serogroups generally do not produce the cholera-causing toxin but do sporadically cause gastroenteritis and extra-intestinal infections. Recently, however, bloodstream infections caused by non-O1/non-O139 V. cholerae are being increasingly reported, and these infections are associated with high mortality in immunocompromised hosts. We describe a case of non-O1/non-O139 V. cholerae bacteremia in a patient with autoimmune pancreatitis and stenosis of the intra- and extrahepatic bile ducts. The clinical manifestations of bacteremia were fever and mild digestive symptoms. The blood cultures showed V. cholerae, which was identified as a non-O1, non-O139 serogroup by slide agglutination tests and PCR. The bloodstream infection of the patient was likely caused by the consumption of contaminated seafood at a banquet. The patient recovered after the administration of a third-generation cephalosporin. Non-O1/non-O139 V. cholerae infection presents with or without gastrointestinal manifestations; close attention should be paid to the possibility of disseminated non-O1/non-O139 V. cholerae infection in high-risk patients.

IgG4-related autoimmune pancreatitis and sclerosing cholangitis: A case report and literature review

RATIONALE

Immunoglobulin G4-related disease (IgG4-RD) can involve various organs throughout the body, primarily manifesting as endocrine dysfunction, visual impairment, jaundice, and limited sexual function. IgG4-related autoimmune pancreatitis is triggered by autoimmune reactions and characterized by structural changes in the pancreas and pancreatic ducts. The disease mainly affects middle-aged and elderly males, typically presenting as progressive painless jaundice and misdiagnosed as cholangiocarcinoma or pancreatic cancer.

PATIENT CONCERNS

This study reports a 54-year-old male who consulted with different institutions multiple times due to diabetes, pancreatitis, elevated liver enzymes, and jaundice.

DIAGNOSES

Magnetic resonance imaging revealed swollen head of the pancreas and atrophic tail. Liver and pancreatic tissue pathology showed IgG4 plasma cell infiltration, while liver biopsy indicated interface hepatitis, liver fibrosis, and pseudolobule formation, with no evidence of bile duct damage.

INTERVENTIONS

Following hormone therapy, the patient's serum IgG4 levels and liver enzyme levels returned to normal.

OUTCOMES

The disease relapsed 2 years after maintaining hormone therapy, and the patient underwent additional hormone-induced remission therapy combined with azathioprine.

LESSONS

The purpose of this research report is to enhance the awareness and understanding of IgG4-RD, emphasizing the necessity for personalized treatment strategies that take into account its recurrence, associations, and imaging features. This report provides valuable insights and guidance for clinicians in managing and diagnosing patients with IgG4-RD.

Autoimmune pancreatitis: Biopsy interpretation and differential diagnosis

Autoimmune pancreatitis (AIP) is classified into type 1 (IgG4-related) and type 2 (IgG4-unrelated) and the interpretation of pancreatic biopsy findings plays a crucial role in their diagnosis. Needle biopsy of type 1 AIP in the acute or subacute phase shows a diffuse lymphoplasmacytic infiltrate, storiform fibrosis, obliterative phlebitis, and the infiltration of many IgG4-positive plasma cells. In a later phase, changes become less inflammatory and more fibrotic, making interpretations more challenging. Confirmation of the lack of 'negative' findings that are unlikely to occur in type 1 AIP (e.g., neutrophilic infiltration, abscess) is important to avoid an overdiagnosis. The number of IgG4-positive plasma cells increases to >10 cells/high-power field (hpf), and the IgG4/IgG-positive plasma cell ratio exceeds 40 %. However, these are minimal criteria and typical cases show >30 positive cells/hpf and a ratio >70 % even in biopsy specimens. Therefore, cases with a borderline increase in this number or ratio need to be diagnosed with caution. In cases of ductal adenocarcinoma, the upstream pancreas rarely shows type 1 AIP-like changes; however, the ratio of IgG4/IgG-positive plasma cells is typically <40 %. Although the identification of a granulocytic epithelial lesion (GEL) is crucial for type 2 AIP, this finding needs to be interpreted in conjunction with a background dense lymphoplasmacytic infiltrate. An isolated neutrophilic duct injury can occur in peritumoral or obstructive pancreatitis. Drug-induced pancreatitis in patients with inflammatory bowel disease often mimics type 2 AIP clinically and pathologically. IL-8 and PD-L1 are potential ancillary immunohistochemical markers for type 2 AIP, requiring validation studies.

Autoimmune pancreatitis: Cornerstones and future perspectives

Autoimmune pancreatitis (AIP) is an autoimmune subtype of chronic pancreatitis resulting from the aberrant immune response against the pancreas, leading to inflammation and fibrosis. Although AIP is rare, its incidence is increasing and is often misdiagnosed as other pancreatic diseases. AIP is commonly classified into two types. Type 1 AIP (AIP-1) is typically associated with elevated serum immunoglobulin G4 (IgG4) levels and systemic manifestations, while type 2 AIP is typically a more localized form of the disease, and may coexist with other autoimmune disorders, especially inflammatory bowel diseases. Additionally, there is emerging recognition of a third type (type 3 AIP), which refers to immunotherapy-triggered AIP, although this classification is still gaining acceptance in medical literature. The clinical manifestations of AIP mainly include painless jaundice and weight loss. Elevated serum IgG4 levels are particularly characteristic of AIP-1. Diagnosis relies on a combination of clinical, laboratory, radiological, and histological findings, given the similarity of AIP symptoms to other pancreatic disorders. The mainstay of treatment for AIP is steroid therapy, which is effective in most cases. Severe cases might require additional imm-unosuppressive agents. This review aims to summarize the current knowledge of AIP, encompassing its epidemiology, etiology, clinical presentation, diagnosis, and treatment options. We also address the challenges and controversies in diagnosing and treating AIP, such as distinguishing it from pancreatic cancer and managing long-term treatment, highlighting the need for increased awareness and knowledge of this complex disease.

Significantly Elevated CA 19-9 after COVID-19 Vaccination and Literature Review of Non-Cancerous Cases with CA 19-9 > 1000 U/mL

BACKGROUND

CA 19-9 is a commonly assessed tumor marker, considered characteristic of pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers; however, the positive predictive value of CA 19.9 is too low, and the usage of CA 19.9 as a screening tool in the healthy population remains controversial.

METHODS

The presented case illustrates a reversed diagnosis of highly elevated serum CA 19-9 levels in a 54-year-old female complaining of pain in the epigastric region, shortly after COVID-19 vaccination. Laboratory tests showed a significantly elevated level of the CA 19-9 marker (>12,000 U/mL, reference value: <37 U/mL) with normal pancreatic enzyme activity. The patient underwent imaging examination, which showed no abnormalities, except for increased pancreatic dimension and areas of fluid signal in the pancreas in magnetic resonance imaging (MRI), which may correspond to autoimmune pancreatitis (AIP). The patient remains asymptomatic with a recommendation for a follow-up MRI in 12 months.

RESULTS

A literature review conducted revealed multi-causal CA 19-9 increases above 1000 U/mL, including non-cancerous diseases of the lung, pancreas, liver, ovary, kidney, and others. The median concentration of CA 19-9 regardless of the cause of disease was 2810 U/mL (IQR ± 6895). The median CA 19-9 values in men and women were 3500 (IQR ± 10,050) and 2455 (IQR ± 3927), respectively, and differ significantly between the compared groups (p < 0.05). There was no difference between CA 19-9 values and the categorized cause of the increase.

CONCLUSIONS

Conducting differential diagnosis, it should not be forgotten that most international guidelines recommend the use of CA 19-9 only in conjunction with pathology of pancreas in radiological imaging; however, even such a combination can point the diagnostic pathway in the wrong direction. A highly elevated CA 19-9 level, typically associated with PDAC, may be the result of benign disease including AIP related to COVID-19 vaccination.

[Autoimmune pancreatitis versus pancreatic cancer]

CLINICAL ISSUE

Autoimmune pancreatitis (AIP) is classified as a distinct form of pancreatitis according to the guidelines. It is characterized by imaging morphologic and histologic features and is associated with extrapancreatic manifestations in type 1 IgG 4-associated disease. Symptoms and findings almost always improve with administration of steroids. Differentiation from pancreatic ductal adenocarcinoma is required, particularly in the presence of AIP with focal parenchymal involvement.

STANDARD RADIOLOGIC PROCEDURES

If AIP is suspected, abdominal ultrasound and/or endosonography, computed tomography (CT), and preferably magnetic resonance imaging (MRI) are indicated. A distinction is made between parenchymal and ductal changes that specifically indicate the presence of AIP.

METHODOLOGICAL INNOVATIONS AND EVALUATION

The diagnosis of autoimmune pancreatitis should be made based on the International Consensus Criteria (ICDC), in which the five main features (imaging, serology, histology, other organ involvement, response to steroid medication) are assessed. In type 1 AIP, typical imaging changes are sufficient to establish the diagnosis even with negative histology, whereas for type 2 AIP, histologic evidence is required. Imaging changes help in the differential diagnosis from pancreatic cancer.

PRACTICAL RECOMMENDATIONS

The following article addresses and evaluates crucial imaging diagnostic CT and MRI criteria for correct classification of findings, description of results, and differentiation of autoimmune pancreatitis from pancreatic cancer.

Pancreatic Cancer and Its Mimics

Pancreatic ductal adenocarcinoma (PDAC) is the most common primary pancreatic malignancy, ranking fourth in cancer-related mortality in the United States. Typically, PDAC appears on images as a hypovascular mass with upstream pancreatic duct dilatation and abrupt duct cutoff, distal pancreatic atrophy, and vascular encasement, with metastatic involvement including lymphadenopathy. However, atypical manifestations that may limit detection of the underlying PDAC may also occur. Atypical PDAC features include findings related to associated conditions such as acute or chronic pancreatitis, a mass that is isointense to the parenchyma, multiplicity, diffuse tumor infiltration, associated calcifications, and cystic components. Several neoplastic and inflammatory conditions can mimic PDAC, such as paraduodenal "groove" pancreatitis, autoimmune pancreatitis, focal acute and chronic pancreatitis, neuroendocrine tumors, solid pseudopapillary neoplasms, metastases, and lymphoma. Differentiation of these conditions from PDAC can be challenging due to overlapping CT and MRI features; however, certain findings can help in differentiation. Diffusion-weighted MRI can be helpful but also can be nonspecific. Accurate diagnosis is pivotal for guiding therapeutic planning and potential outcomes in PDAC and avoiding biopsy or surgical treatment of some of these mimics. Biopsy may still be required for diagnosis in some cases. The authors describe the typical and atypical imaging findings of PDAC and features that may help to differentiate PDAC from its mimics. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Zins in this issue.

Contrast-enhanced ultrasound and contrast-enhanced computed tomography for differentiating mass-forming pancreatitis from pancreatic ductal adenocarcinoma: a meta-analysis

BACKGROUND

Patients with mass-forming pancreatitis (MFP) or pancreatic ductal adenocarcinoma (PDAC) presented similar clinical symptoms, but required different treatment approaches and had different survival outcomes. This meta-analysis aimed to compare the diagnostic performance of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) in differentiating MFP from PDAC.

METHODS

A literature search was performed in the PubMed, EMBASE (Ovid), Cochrane Library (CENTRAL), China National Knowledge Infrastructure (CNKI), Weipu (VIP), and WanFang databases to identify original studies published from inception to August 20, 2021. Studies reporting the diagnostic performances of CEUS and CECT for differentiating MFP from PDAC were included. The meta-analysis was performed with Stata 15.0 software. The outcomes included the pooled sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) curves of CEUS and CECT. Meta-regression was conducted to investigate heterogeneity. Bayesian network meta-analysis was conducted to indirectly compare the overall diagnostic performance.

RESULTS

Twenty-six studies with 2115 pancreatic masses were included. The pooled sensitivity and specificity of CEUS for MFP were 82% (95% confidence interval [CI], 73%-88%; I2  = 0.00%) and 95% (95% CI, 90%-97%; I2  = 63.44%), respectively; the overall +LR, -LR, and DOR values were 15.12 (95% CI, 7.61-30.01), 0.19 (95% CI, 0.13-0.29), and 78.91 (95% CI, 30.94-201.27), respectively; and the area under the SROC curve (AUC) was 0.90 (95% CI, 0.87-92). However, the overall sensitivity and specificity of CECT were 81% (95% CI, 75-85%; I2  = 66.37%) and 94% (95% CI, 90-96%; I2  = 74.87%); the overall +LR, -LR, and DOR values were 12.91 (95% CI, 7.86-21.20), 0.21 (95% CI, 0.16-0.27), and 62.53 (95% CI, 34.45-113.51), respectively; and, the SROC AUC was 0.92 (95% CI, 0.90-0.94). The overall diagnostic accuracy of CEUS was comparable to that of CECT for the differential diagnosis of MFP and PDAC (relative DOR 1.26, 95% CI [0.42-3.83], P  > 0.05).

CONCLUSIONS

CEUS and CECT have comparable diagnostic performance for differentiating MFP from PDAC, and should be considered as mutually complementary diagnostic tools for suspected focal pancreatic lesions.

A Case of Autoimmune Pancreatitis Presenting As Alcohol-Induced Necrotizing Pancreatitis

Autoimmune pancreatitis (AIP) is an inflammatory condition of the pancreas, commonly characterized by elevated levels of immunoglobulin G (IgG) 4. Diagnosis of this condition can be challenging in patients with risk factors for other pancreatitis etiologies and requires a comprehensive approach utilizing clinical, radiologic, and laboratory findings. Here, we present a case of an individual with a history of multiple prior hospitalizations for alcoholic pancreatitis, who presented with symptoms of abdominal pain, nausea, and vomiting. Computed tomography (CT) imaging revealed intra-abdominal abscesses and findings consistent with pancreatitis. Further laboratory results revealed elevated lipase and IgG4 levels, indicating AIP as the underlying cause. This case highlights the importance of considering AIP as a differential diagnosis in individuals presenting with pancreatic disease.

Thoracoabdominal manifestations of immunoglobulin G4-related disease

Immunoglobulin G4-related disease (IgG4-RD) comprises a group of immune-mediated diseases that, until recently, were considered separate entities. These entities have a similar clinical presentation, serological findings, and pathogenesis, so they are currently considered a single multisystemic disease. The common characteristic is the infiltration of involved tissues by plasma cells and lymphocytes that are positive for IgG4. Three major criteria have been proposed for the diagnosis of IgG4-RD: clinical, laboratory, and histological. The pancreas is the organ that is most affected by IgG4-RD, which can simulate a tumor. In this respect, a series of signs could help us suspect that the pancreatic findings do not reflect a tumor (halo sign, duct-penetrating sign, absence of vascular invasion, etc.). The differential diagnosis is important to avoid unnecessary surgical interventions.

Serum metabolomics study for acute attack of chronic pancreatitis

BACKGROUND & AIMS

Chronic pancreatitis (CP) is an inflammatory disease characterized by irreversible changes. However, acute CP attacks can lead to various complications and affect patient prognosis. Therefore, this study aimed to identify reliable candidate metabolic biomarkers for diagnosing acute CP attacks and complement candidate diagnostic markers for CP.

METHODS

A total of 139 serum specimens were prospectively included in three consecutive exploratory, identification, and validation studies. All samples were analyzed for candidate diagnostic biomarkers and metabolic pathways using a liquid chromatography-mass spectrometer.

RESULTS

Serum metabolic profiles differed between patients with CP and non-pancreatic disease controls, and 239 potential metabolic biomarkers for diagnosing CP were identified. Based on identification and validation studies, Diacylglycerol(16:0/18:4), 16-F1-PhytoP, N-(hexacosanoyl)-tetradecasphing-4-enine, carnosic acid, and Auxin b were identified as biomarkers for distinguishing acute attacks from non-acute attacks in patients with CP. The area under the curve of the Diacylglycerol(16:0/18:4) was 0.969 (95% confidence interval, 0.869-1) in the validation study.

CONCLUSIONS

To the best of our knowledge, this is the first prospective cohort study to identify and validate a metabolomic signature in serum for diagnosing acute attacks of CP. In addition, our study identified 239 potential biomarkers for CP diagnosis.

Eosinophilic pancreatitis with serum IgG4-positivity, potentially associated with autoimmune pancreatitis

A 70-year-old man presented with unprovoked weight loss and intermittent left upper quadrant tenderness for one-and-a-half month. Computed tomography revealed irregular cystic lesions in the pancreatic tail. Endoscopic ultrasonography (EUS) revealed pancreatic tail enlargement and giant, thick-walled cysts surrounding the pancreatic tail with no connection with the pancreatic duct. Endoscopic ultrasonography-guided fine-needle aspiration was performed on the enlarged pancreatic parenchyma and thickened cyst wall. Both biopsies showed hyper eosinophilia and few plasma cells. Endoscopic retrograde pancreatography revealed an irregular narrowing of the main pancreatic duct. Pancreatic juice cytology revealed substantial eosinophilia. Blood sampling showed an elevated eosinophil count and immunoglobulin G4 (IgG4) and immunoglobulin E (IgE) levels at the initial examination. We considered the patient to have eosinophilic pancreatitis (EP) with autoimmune pancreatitis, or alternately, EP with IgG4-related retroperitoneal fibrosis (RPF). Upon prednisolone administration, the abdominal pain improved, the peripheral blood eosinophil count decreased to zero, IgG4 and IgE levels decreased, pancreatic enlargement improved, and the cystic lesions disappeared. The condition did not recur within the following 3 years. Both EP and EP with IgG4-related RPF are rare etiologies of pancreatitis, and this case is very instructive.

The role of ion channels in immune-related diseases

Ion channel is an integral membrane protein that allows the permeation of charge ions across hydrophobic phospholipid membranes, including plasma membranes and organelle membranes (such as mitochondria, endoplasmic reticulum and vacuoles), which are widely distributed in various cells and tissues, such as cardiomyocytes, smooth muscle cells, and nerve cells. Ion channels establish membrane potential by regulating ion concentration and membrane potential. Membrane potential plays an important role in cells. Studies have shown that ion channels play a role in a number of immune-related diseases caused by functional defects in ion channels on immune or non-immune cells in major human organs, usually affecting specific organs or multiple organs. The present review discusses the relationship between ion channels and immune diseases in major organs of the human body.

The research progress of anti-inflammatory and anti-fibrosis treatment of chronic pancreatitis

Chronic pancreatitis (CP) is a chronic progressive inflammatory disease of the pancreas, caused by multiple factors and accompanied by irreversible impairment of pancreatic internal and external secretory functions. Pathologically, atrophy of the pancreatic acini, tissue fibrosis or calcification, focal edema, inflammation, and necrosis are observed. Clinical manifestations include recurrent or persistent abdominal pain, diarrhea, emaciation, and diabetes. In addition, CP is prone to develop into pancreatic cancer(PC) due to persistent inflammation and fibrosis. The disease course is prolonged and the clinical prognosis is poor. Currently, clinical treatment of CP is still based on symptomatic treatment and there is a lack of effective etiological treatment. Encouragingly, experiments have shown that a variety of active substances have great potential in the etiological treatment of chronic pancreatitis. In this paper, we will review the pathogenesis of CP, as well as the research progress on anti-inflammatory and anti-fibrotic therapies, which will provide new ideas for the development of subsequent clinical studies and formulation of effective treatment programs, and help prevent CP from developing into pancreatic cancer and reduce the prevalence of PC as much as possible.

Autoimmune Pancreatitis: From Pathogenesis to Treatment

Autoimmune pancreatitis (AIP) is a rare disease. The diagnosis of AIP is difficult and should be made by a comprehensive evaluation of clinical, radiological, serological, and pathological findings. Two different types of AIP have been identified: autoimmune pancreatitis type 1 (AIP-1), which is considered a pancreatic manifestation of multiorgan disease related to IgG4, and autoimmune pancreatitis type 2 (AIP-2), which is considered a pancreas-specific disease not related to IgG4. Although the pathophysiological conditions seem to differ between type 1 and type 2 pancreatitis, both respond well to steroid medications. In this review, we focused on the pathogenesis of the disease to develop a tool that could facilitate diagnosis and lead to the discovery of new therapeutic strategies to combat autoimmune pancreatitis and its relapses. The standard therapy for AIP is oral administration of corticosteroids. Rituximab (RTX) has also been proposed for induction of remission and maintenance therapy in relapsing AIP-1. In selected patients, immunomodulators such as azathioprine are used to maintain remission. The strength of this review, compared with previous studies, is that it focuses on the clear difference between the two types of autoimmune pancreatitis with a clearly delineated and separate pathogenesis. In addition, the review also considers various therapeutic options, including biologic drugs, such as anti-tumor necrosis factor (TNF) therapy, a well-tolerated and effective second-line therapy for AIP type 2 relapses or steroid dependence. Other biologic therapies are also being explored that could provide a useful therapeutic alternative to corticosteroids and immunosuppressants, which are poorly tolerated due to significant side effects.

The Pancreas and Known Factors of Acute Pancreatitis

Pancreatitis is regarded by clinicians as one of the most complicated and clinically challenging of all disorders affecting the abdomen. It is classified on the basis of clinical, morphological, and histological criteria. Causes of acute pancreatitis can easily be identified in 75–85% of patients. The main causes of acute, recurrent acute, and chronic pancreatitis are gallstone migration and alcohol abuse. Other causes are uncommon, controversial, or unexplained. For instance, cofactors of all forms of pancreatitis are pancreas divisum and hypertriglyceridemia. Another factor that should be considered is a complication of endoscopic retrograde cholangiopancreatography: post-endoscopic retrograde cholangiopancreatography acute pancreatitis. The aim of this study is to present the known risk factors for acute pancreatitis, beginning with an account of the morphology, physiology, and development of the pancreas.

Associations between autoimmune dysfunction and pollutants in Akwesasne Mohawk women: Dichlorodiphenyltrichloroethane and polychlorinated biphenyl exposure

BACKGROUND

Pollutant exposures, including polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), have been found to disrupt normal immune function. Native American communities are disproportionately affected by autoimmune dysfunction and are more likely to be exposed to harmful pollutants than the general population.

OBJECTIVE

To determine the association between autoimmune dysfunction and pollutant exposure levels, this study evaluates the statistical relationship between the presence of autoimmune dysfunction and pollutant exposure.

METHODS

Information was collected from Akwesasne Mohawk women (n = 182), 21-39 years of age, between 2009 and 2013. Data collection included anthropometric measurements, medical diagnoses of autoimmune disease and symptoms of autoimmune dysfunction in the medical record, and blood draws for measurement of pollutants. Multivariate analyses determined the association between toxicant exposure and autoimmune dysfunction.

RESULTS

Toxicant p,p'-DDE was positively associated with an almost two-fold risk of autoimmune dysfunction. p,p'-DDE and PCB congeners 32, 136, and 138 were positively associated in a multivariate analysis with an autoimmune diagnosis.

CONCLUSIONS

Pollutant exposures, specifically to p,p'-DDE and some PCB congeners, are common exposures that are associated with autoimmune dysfunction and autoimmune disease, although there are other factors and causes related to autoimmune dysfunction incidence.

Spontaneous remission of autoimmune pancreatitis: Four case reports

BACKGROUND

Autoimmune pancreatitis (AIP) is a particular type of chronic pancreatitis, and steroid treatment of AIP is effective. Spontaneous remission (SR) of AIP without steroids is relatively rare. The international consensus for the treatment of autoimmune pancreatitis suggests that patients with AIP with obstructive jaundice, abdominal pain, and back pain related to the pancreas or the bile duct should be treated with steroids; most asymptomatic patients with AIP may improve without steroids. However, in our clinical work, we found that the clinical characteristics of AIP patients with SR vary. Four of these cases are described here. In addition, to our knowledge, there is no previously published report of dynamic imaging before and after SR of AIP at present.

CASE SUMMARY

We present the cases of four patients with AIP (two females and two males) in which the AIP improved spontaneously without steroid treatment. Two patients were asymptomatic, one patient had abdominal pain with obstructive jaundice, and one patient had intermittent right upper abdominal pain. Three patients presented with localized pancreatic enlargement and one with diffuse pancreatic enlargement. In addition to the pancreatic lesions, bile duct involvement was seen in two patients, and no extra-pancreatic organ involvement was found in the other two patients. The serum IgG4 level of all patients was more than twice the normal level. After SR in the four patients, the affected pancreases exhibited three types of image features: Return to normal, progressive fibrosis, and atrophy and calcification.

CONCLUSION

The clinical features of SR in our four patients with AIP differ, but the imaging findings share some characteristics. After SR, in some cases the affected pancreas could return to normal, although some patients suffer from progressive fibrosis and atrophy as well as calcification.

Diagnosis and Treatment of Acute Pancreatitis

The pancreas is a glandular organ that is responsible for the proper functioning of the digestive and endocrine systems, and therefore, it affects the condition of the entire body. Consequently, it is important to effectively diagnose and treat diseases of this organ. According to clinicians, pancreatitis—a common disease affecting the pancreas—is one of the most complicated and demanding diseases of the abdomen. The classification of pancreatitis is based on clinical, morphologic, and histologic criteria. Medical doctors distinguish, inter alia, acute pancreatitis (AP), the most common causes of which are gallstone migration and alcohol abuse. Effective diagnostic methods and the correct assessment of the severity of acute pancreatitis determine the selection of an appropriate treatment strategy and the prediction of the clinical course of the disease, thus preventing life-threatening complications and organ dysfunction or failure. This review collects and organizes recommendations and guidelines for the management of patients suffering from acute pancreatitis.

Pancreatic Incidentaloma

Pancreatic incidentalomas (PIs) represent a clinical entity increasingly recognized due to advances in and easier access to imaging techniques. By definition, PIs should be detected during abdominal imaging performed for indications other than a pancreatic disease. They range from small cysts to invasive cancer. The incidental diagnosis of pancreatic cancer can contribute to early diagnosis and treatment. On the other hand, inadequate management of PIs may result in overtreatment and unneeded morbidity. Therefore, there is a strong need to evaluate the nature and clinical features of individual PIs. In this review, we summarize the major characteristics related to PIs and present suggestions for their management.

Case Series of Autoimmune Pancreatitis and IgG4-Related Sclerosing Cholangitis

IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease that can involve any organ. The involvement of the pancreas and biliary tract is the most common and well-studied in the literature. It is characterized by a non-specific presentation, mimicking a malignant process. The goal was to look at the different clinical and paraclinical aspects of this disease, as well as the challenges that come from its management. It was made up of three observations of patients with IgG4-RD involving the biliary tract and pancreas. The first observation concerned intrahepatic biliary cholangitis that was accompanied by porto-mesenteric thrombosis, which was discovered by cholestatic jaundice on the 15th day after an appendectomy, and the patient improved under corticosteroids and anticoagulants. The second observation concerned an acute revelation of the disease. It was an acute attack of chronic pancreatitis of IgG4-RD. The main symptoms were pancreatic pain and exocrine pancreatic insufficiency, and corticosteroid therapy allowed remission. The third observation was related to autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis, revealed by jaundice with cholestasis. The patient acquired corticosteroid resistance and an adverse progression to decompensated cirrhosis, and liver transplantation was indicated. The clinical presentation of IgG4-RD is heterogeneous, as evidenced by our three clinical observations. There are still significant gaps in our understanding, particularly in terms of pathogenesis and factors that influence therapy response. Further observational and interventional research is needed to better manage this disease.

Correlation of Autoimmune Pancreatitis and Malignancy: Systematic Review and Meta-Analysis

BACKGROUND

There is conflicting evidence regarding autoimmune pancreatitis (AIP) association with pancreatic and non-pancreatic cancers. Literature lacks data on overall prevalence of malignancies in autoimmune pancreatitis.

AIM

Given the lack of definite evidence, we aimed to pool and summarize data from available literature regarding prevalence of different malignancies in AIP.

METHODS

We conducted a systematic search of MEDLINE, EMBASE, Cochrane Register of Controlled Trials, and Web of Science through February 16, 2021, to include observational studies assessing the incidence of cancer in AIP. We used the DerSimonian-Laird method with random effects for meta-analysis. Pooled prevalence, 95% confidence interval (CI), and I² statistic are reported.

RESULTS

A total of 17 studies with 2746 patients were included assessing the prevalence of cancer in AIP. The overall prevalence of cancer in AIP was 9.6% [95% confidence interval (CI), 5.7-13.5%]. The cancers with the highest prevalence in AIP population were gastric and colorectal cancer, with prevalence of 1.3% (95% CI, 0.5-2.1%) and 1.2% (95% CI, 0.6-1.8%), respectively.

CONCLUSION

We demonstrate the prevalence of different cancers in AIP. Inflammatory surge in AIP and subsequent carcinogenesis is one explanation for this association. Moreover, AIP can be a paraneoplastic syndrome manifestation of malignancies.

Differential EUS findings in focal type 1 autoimmune pancreatitis and pancreatic cancer: A proof-of-concept study

BACKGROUND AND OBJECTIVES

Autoimmune pancreatitis (AIP) often mimics pancreatic cancer (PC), particularly if presenting as a focal lesion. EUS may orient the differential diagnosis between them. This study aims to identify EUS findings that might be useful to differentiate type 1 focal autoimmune pancreatitis (f-AIP1) and PC.

MATERIALS AND METHODS

F-AIP1 and PC patients were retrospectively collected, matched, and compared. EUS findings considered were: focal mass echogenicity, loss of lobularity, distal atrophy, peripancreatic hypoechoic margins (PHM), pancreatic duct dilation, duct-penetrating sign (DPS), pancreatic/common bile duct thickened walls (PD/CBD-TW), and vessel infiltration (VI). Elastography findings were also recorded. Variables with a P < 0.05 at univariate analysis were included in logistic multiple regression.

RESULTS

Fifteen patients with f-AIP and 60 with PC were studied. FE was hypoechoic in all patients from both groups. PHM was observed in 40% of f-AIP1 cases but not in PC ones (P < 0.001). DPS was found in 10/15 (66.7%) f-AIP1 and in 7/60 (11.7%) PC patients (P < 0.001). PD-TW and CBD-TW were observed in 66.7%/60% f-AIP1 cases and in 6.7%/13.6% PC patients, respectively (P < 0.001 for both comparisons). Pancreatic masses were significantly different at EUS elastography (elastic respectively in 71.4% f-AIP1 and 3.8% PC, P < 0.001). VI was suspected in 20% of f-AIPs and 85% of PCs (P < 0.001). At multiple regression, PD-TW, CBD-TW, elastic pattern, and the absence of VI independently supported a diagnosis of f-AIP1.

CONCLUSIONS

Our results suggest that EUS findings deserve consideration in the diagnostic workup of AIP to improve the differential diagnosis with PC.

IgG4-Related Disease: Mimickers and Diagnostic Pitfalls

BACKGROUND

The tendency of IgG4-related disease (IgG4-RD) to form pseudotumors, as well as its multisystemic nature, makes it the perfect mimicker of many conditions. Moreover, some clinical, serological, radiological, or histological features of the disease might be shared with some mimickers.Recently, 4 clinical phenotypes have been identified, and patients grouped in each phenotype have distinctive demographic, clinical, and serological features and outcomes, and, as expected, for each phenotype, a set of differential diagnoses should be considered.

SUMMARY OF THE LITERATURE

The main differential diagnoses for the pancreato-hepato-biliary phenotype are pancreatic adenocarcinoma and cholangiocarcinoma. Other differential diagnoses include type 2 autoimmune pancreatitis and primary sclerosing cholangitis. In patients with retroperitoneal/aortic phenotype, inflammatory conditions such as idiopathic retroperitoneal fibrosis and large vessel vasculitides should be ruled out, and most of the time, a biopsy will be needed to exclude malignancies. In head and neck limited phenotype, autoimmune conditions (eg, granulomatosis with polyangiitis, Graves orbitopathy, sarcoidosis), malignancies, and histiocytosis should be ruled out, whereas the main differential diagnoses of the Mikulicz/systemic phenotype are Sjögren syndrome, granulomatosis with polyangiitis, and multicentric Castleman disease.

CONCLUSIONS

Approaching a patient with probable IgG4-RD through a clinical phenotype framework will ease the diagnostic algorithm and facilitate the prompt recognition of the disease. There are certain clinical, serological, radiological, and histological features in each clinical phenotype that, if present, increase the likelihood that a patient may have IgG4-RD instead of the mimicker condition. Those clues that point toward IgG4-RD diagnosis should be actively sought in the workup of patients.

Persistent enlargement of the pancreatic gland after glucocorticoid therapy increases the risk of relapse in IgG4-related autoimmune pancreatitis

OBJECTIVES

This study aims to clarify the relationship between the changes of pancreatic size after glucocorticoid (GC) therapy and relapse in IgG4-related autoimmune pancreatitis (AIP).

METHODS

We prospectively enrolled 205 newly diagnosed IgG4-related AIP patients. 145 patients were followed up for more than 3 years. These patients were divided into three groups according to the changes of pancreatic size after treatment of 6 months: pancreatic swelling, normal size, and pancreatic atrophy. Baseline clinical and laboratory parameters were compared among three groups. Kaplan-Meier survival analysis was performed in the 134 patients based on GC therapy. Besides, Cox regression analysis and logistic regression analysis were performed to identify risk factors associated with relapse and the potential variables affecting changes of pancreatic size after treatment.

RESULTS

Age at diagnosis, white blood cell count, and serum IgG1 level at baseline were significantly different among the three groups. After treatment of 6 months, the pancreas of most patients (n = 81, 55.9%) could return to normal size, while persistent pancreatic swelling was found in 24.1% patients (n = 35), and atrophy was observed in 20.0% of the patients (n = 29). Kaplan-Meier survival analysis presented patients with pancreatic swelling after 6 months of GC therapy were more likely to relapse in the follow-up of 3 years. Persistent pancreatic swelling after treatment and salivary gland involvement at baseline were independent risk variables associated with relapse in IgG4-related AIP patients, while GC-based therapy was a protective factor of relapse. Logistic regression analysis revealed that older age at diagnosis was associated with pancreatic atrophy and higher baseline serum IgG1 level was associated with pancreatic swelling after treatment of 6 months.

CONCLUSIONS

Patients with persistent pancreatic swelling after GC-based therapy of 6 months were more likely to relapse in the follow-up of 3 years. Older age at diagnosis and higher baseline serum IgG1 level were potential variables associated with pancreatic atrophy or swelling after treatment of 6 months. Key Points • Patients with persistent pancreatic swelling after glucocorticoid-based therapy were more likely to relapse in IgG4-related autoimmune pancreatitis. • Older age at diagnosis was associated with pancreatic atrophy after glucocorticoid-based therapy. • Higher baseline serum IgG1 level was associated pancreatic swelling after glucocorticoid-based therapy.

Pancreatic Disorders in Patients with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) can involve multiple organ systems, and pancreatic manifestations of IBD are not uncommon. The incidence of several pancreatic diseases is more frequent in patients with Crohn's disease and ulcerative colitis than in the general population. Pancreatic manifestations in IBD include a heterogeneous group of disorders and abnormalities ranging from mild, self-limited disorders to severe diseases. Asymptomatic elevation of amylase and/or lipase is common. The risk of acute pancreatitis in patients with IBD is increased due to the higher incidence of cholelithiasis and drug-induced pancreatitis in this population. Patients with IBD commonly have altered pancreatic histology and chronic pancreatic exocrine dysfunction. Diagnosing acute pancreatitis in patients with IBD is challenging. In this review, we discuss the manifestations and possible causes of pancreatic abnormalities in patients with IBD.

Application of dynamic contrast enhanced ultrasound in distinguishing focal-type autoimmune pancreatitis from pancreatic ductal adenocarcinoma

OBJECTIVE

To explore the value of dynamic contrast enhanced ultrasound (DCE-US) in preoperative differential diagnosis of focal-type autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC).

PATIENTS AND METHODS

From May 2016 to March 2020, patients with biopsy and histopathologically confirmed focal-type AIP (n = 9) were retrospectively included. All patients received contrast enhanced ultrasound (CEUS) examinations one week before surgery/biopsy. Dynamic analysis was performed by VueBox® software (Bracco, Italy). Eighteen cases of resection and histopathologically proved PDAC lesions were also included as control group. B mode ultrasound (BMUS) features, CEUS enhancement patterns, time intensity curves (TICs) and CEUS quantitative parameters were obtained and compared between AIP and PDAC lesions.

RESULTS

After injection of ultrasound contrast agents, most focal-type AIP lesions displayed hyper-enhancement (2/9, 22.2%) or iso-enhancement (6/9, 66.7%) during arterial phase of CEUS, while most of PDAC lesions showed hypo-enhancement (88.9%) (P < 0.01). During late phase, most of AIP lesions showed iso-enhancement (8/9, 88.9%), while most of PDAC lesions showed hypo-enhancement (94.4%) (P < 0.001). Compared with PDAC lesions, TICs of AIP lesions showed delayed and higher enhancement. Among all CEUS perfusion parameters, ratio of PE (peak enhancement), WiAUC (wash-in area under the curve), WiR (wash-in rate), WiPI (wash-in perfusion index, WiPI = WiAUC/ rise time), WoAUC (wash-out area under the curve), WiWoAUC (wash-in and wash-out area under the curve) and WoR (wash-out rate) between pancreatic lesion and surrounding normal pancreatic tissue were significantly higher in AIP lesions than PDAC lesions (P < 0.05).

CONCLUSION

DCE-US with quantitative analysis has the potential to make preoperative differential diagnosis between focal-type AIP and PDAC non-invasively.

Solid pancreatic masses in children: A review of current evidence and clinical challenges

Pancreatic tumors in children are infrequently encountered in clinical practice. Their non-specific clinical presentation and overlapping imaging characteristics often make an accurate preoperative diagnosis difficult. Tumors are categorized as epithelial or non-epithelial, with epithelial tumors further classified as tumors of the exocrine or endocrine pancreas. Although both are tumors of the exocrine pancreas, solid pseudopapillary neoplasm is the most prevalent solid pancreatic tumor in children, while pancreatoblastoma is the most common malignant tumor. Insulinoma is the most common pediatric pancreatic tumor of the endocrine pancreas. Malignant tumors require a complete, often radical, surgical resection. However, pancreatic parenchyma-sparing surgical procedures are utilized for benign tumors and low-grade malignancy to preserve gland function. This review will discuss the epidemiology, pathophysiology, clinical and diagnostic characteristics, and management options associated with both common and rare solid pancreatic masses in children. We will also discuss current challenges encountered in their evaluation and treatment.

Fatal Immune Checkpoint Inhibitor-related Pancreatitis

We herein report a case of fatal pancreatitis induced by an immune checkpoint inhibitor. A 62-year-old man with cancer of unknown primary was treated with pembrolizumab. After 12 cycles, immune-related pneumonitis developed and was treated with prednisolone. Three months later, pancreatitis developed, which was successfully treated with hydration and protease inhibitors. Eight months later, another attack of pancreatitis occurred, which did not respond to therapy, including high-dose corticosteroids, and he eventually died. This is the first report describing fatal immune checkpoint inhibitor-related pancreatitis. Despite the rarity of this complication, attention should be paid to its potential severity and treatment.

Autoimmune pancreatitis: What we know so far

Autoimmune pancreatitis (AIP) is a rare, often‐missed disease that involves inflammation of the pancreas and strictures of the pancreatic duct. Its prevalence and incidence in the United States remain scarce. The disease has a varied presentation and often mimics pancreatic malignancy, which can make the diagnosis challenging. Most patients have an excellent response to corticosteroid therapy. Immunomodulators may be used in some cases. Rituximab is an effective, emerging treatment in steroid‐refractory cases. This study aims to review the two distinct types of AIP and provide a detailed analysis of the diagnostic approach and treatment modalities.

Focal IgG4-related autoimmune pancreatitis with distal choledochal adenocarcinoma: a rare case report

Background

Autoimmune pancreatitis (AIP) is a rare disease that manifests as pancreatic involvement in systemic IgG4-related disease (IgG4-RD), a special type of chronic pancreatitis caused by autoimmune abnormalities. The main imaging manifestations of IgG4-related AIP consist of diffuse or localized pancreatic enlargement and irregular pancreatic duct narrowing. The diagnosis of AIP is challenging because it can present with focal lesions, similar to radiologically bile duct cancer or pancreatic cancer.

Case presentation

A 55-year-old male patient was admitted with painless jaundice and multiple radiographic findings of pancreatic head mass, as well as intrahepatic and extrahepatic bile duct dilatation. Various imaging methods indicated pancreatic cancer. However, the endoscopic ultrasonography guided fine needle aspiration (EUS-FNA) and a laparoscopic pancreatic biopsy suggested an IgG4-related AIP. After one month, magnetic resonance imaging showed that the lesion had slightly grown. Combined with CA19-9 and other indexes, the possibility of malignancy was high and there were still surgical indications. The pathological analysis following a pancreaticoduodenectomy revealed poorly differentiated adenocarcinoma in the distal common bile duct.

Conclusion

To date, few reports have described pancreatic or extrapancreatic malignancies in AIP patients, and no association between AIP and bile duct adenocarcinoma has been previously confirmed. This case discuss the differentiation between AIP and malignancy, recent research progress, and the correlation between the two diseases, highlights the importance of carefully evaluating patients with AIP to rule out potential tumors, as well as the critical need for follow up treatment.

Clinical characteristics of autoimmune pancreatitis: Analysis of 19 cases and a literature review

BACKGROUND

Autoimmune pancreatitis (AIP) is an immune-mediated disease characterized by pancreatic enlargement, lymphoplasmic cell infiltration, and storiform fibrosis. The pathogenesis is not clear, the epidemiological data in China is still limited, the clinical manifestations are mostly non-specific, and the onset is insidious. Therefore, summarizing the clinical characteristics and prognosis of the disease can guide its diagnosis and treatment in the future.

AIM

To analyze the clinical manifestation, serology, imaging features, diagnostic methods, and therapy of autoimmune pancreatitis (AIP).

METHODS

A retrospective study was conducted on 19 patients with AIP, who visited the Beijing Shijitan Hospital of Capital Medical University from January 2011 to May 2020. AIP was diagnosed according to the international consensus diagnostic criteria (ICDC) established at the 2010 Congress of the International Association of Pancreatology.

RESULTS

The sex ratio (male-to-female) was 16:3. The mean age was 71.0 ± 10.7 years. All of the cases met the diagnostic criteria for AIP type 1. The common symptoms in patients with AIP were obstructive jaundice, hyperglycemia, weight loss, anorexia, fatigue, and abdominal distension. Complications mostly involved the bile duct, lymph nodes, and thyroid gland. IgG4 was increased in 16 patients, all higher than twice normal upper limit; bilirubin was increased in 11 patients; CA199 was increased significantly in 11 patients, but decreased significantly after treatment (P < 0.05). Ultrasound can be used as a screening examination for AIP. CT and MRI were the most importantly used imaging modalities in AIP, and the typical signs were diffuse or local enlargement of the pancreas. EUS also had clinical diagnostic value. The majority of the patients (16/19) received glucocorticoid therapy, six of which were treated with immunosuppressive agents. Two cases were untreated. One case was misdiagnosed and underwent surgery. Most of the patients (14/16) who were treated with steroid had alleviated clinical symptoms and radiological signs, of whom one relapsed, and one died from unknown cause. There was no significant change in the two untreated patients during the follow-up period. One case died after surgery.

CONCLUSION

AIP is a rare clinical disease, and its clinical manifestations and serological indicators are not specific.

Type 2 Autoimmune Pancreatitis: Consensus and Controversies

Autoimmune pancreatitis (AIP) has attracted much attention in the last two decades, and due to the diagnostic value of immunoglobulin G4 (IgG4), the number of cases diagnosed in clinical practice has markedly increased. However, in contrast to prototypic IgG4-related type 1 AIP, a minor subtype of AIP, referred to as type 2 AIP, is less widely known and has thus not yet been characterized in detail. Type 2 AIP is unrelated to IgG4 and is a completely distinct entity from type 1 AIP. One confusing factor is that the two types of AIP share patterns of clinical presentation (e.g., acute pancreatitis and painless jaundice) and imaging abnormalities (e.g., diffuse or segmental enlargement). Since there are currently no established serum markers, the diagnosis of type 2 AIP is highly challenging and requires the tissue confirmation of neutrophilic injury to the pancreatic ducts, a finding designated as a granulocytic epithelial lesion. Approximately one-third of cases are associated with inflammatory bowel disease, particularly ulcerative colitis; however, the pathological relationship between these two conditions has not yet been clarified. Unanswered questions relate to its pathophysiology, the potential development of a similar granulocytic injury in other organs, and the characteristics of pediatric cases. This review summarizes consensus and controversies surrounding type 2 AIP, with the aim of increasing awareness and highlighting the unmet needs of this underrecognized condition.

Clinical Perspectives on IgG4-Related Disease and Its Classification

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease. Since its discovery nearly two decades ago, our understanding of its pathophysiology and clinical manifestations has grown substantially. Early diagnosis and treatment of this elusive disease can prevent substantial organ damage from end-stage fibrosis, emphasizing the need for prompt recognition and accurate characterization of IgG4-RD. The classification criteria endorsed by the American College of Rheumatology and the European Alliance of Associations for Rheumatology in 2019 provide a framework for establishing the diagnosis in the clinical setting. This process involves recognizing the typical manifestations of the disease and incorporating clinical, radiological, serological, and histopathological information as well as excluding disease mimickers. Glucocorticoids and rituximab are effective at inducing remission in IgG4-RD in most patients, but the optimal approach to long-term management of IgG4-RD remains an area of active clinical research. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Acute pancreatitis in children: a review with clinical perspectives to enhance imaging interpretation

Pediatric acute pancreatitis has distinct etiologic, clinical and prognostic characteristics in contrast to the adult form of the disease. This review offers a comprehensive imaging update that emphasizes the importance of recognizing specific findings that are relevant from the clinical standpoint. Knowledge of these features facilitates communication among multidisciplinary team members and ultimately could lead to the improved care of pediatric acute pancreatitis patients.

Effective apparent diffusion coefficient parameters for differentiation between mass-forming autoimmune pancreatitis and pancreatic ductal adenocarcinoma

PURPOSE

To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) parameters by region of interest (ROI) methods in differentiating mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).

METHODS

The institutional review board approved this retrospective study and the requirement for informed consent was waived. Twenty-three patients with mass-forming AIP and 144 patients with PDAC underwent diffusion-weighted imaging with b-values of 0 s/mm² and 800 s/mm². The minimum, maximum, and mean ADC values obtained by placing ROIs within lesions and percentile ADC values (10th, 25th, 50th, 75th, and 90th) from entire-lesion histogram analysis were compared between the two groups by using Mann-Whitney U tests. The diagnostic performance was evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

The minimum, maximum, and mean ADC values were significantly different between mass-forming AIP and PDAC groups. ROC curve analysis showed that the maximum ADC had the highest diagnostic performance (0.92), while the minimum ADC value had the lowest diagnostic performance (0.72). The AUC of minimum ADC was significantly lower than that of maximum or mean ADC (P < 0.0001, P < 0.0001). The AUC was lowest in 10th percentile ADC value and highest in 90th percentile value. The AUC increased along with the increase of percentile values.

CONCLUSION

Either the maximum or mean ADC value was effective in differentiating mass-forming AIP from the PDAC group, while the minimum ADC value might not be recommended.

Mass Mimicking Autoimmune Pancreatitis—A Report of Two Cases and Review of Literature

Autoimmune pancreatitis (AIP) consists of two clinically histologically distinct forms (type I and II) of chronic pancreatitis that are histologically different. These forms of AIP classically respond to oral steroids. The focal form of AIP resembles pancreatic carcinoma both clinically and radiologically and it is of utmost importance to make an early correct diagnosis between these two diseases in order to identify the optimal therapeutic strategy and to avoid unnecessary laparotomy or pancreatic resection in AIP patients. Here we report focal forms of type I and II AIP with clinical and imaging features closely mimicking pancreatic carcinoma.

Distinguishing pancreatic cancer and autoimmune pancreatitis with in vivo tomoelastography

OBJECTIVES

To prospectively investigate the stiffness and fluidity of pancreatic ductal adenocarcinoma (PDAC) and autoimmune pancreatitis (AIP) with tomoelastography, and to evaluate its diagnostic performance in distinguishing the two entities.

METHODS

Tomoelastography provided high-resolution maps of shear wave speed (c in m/s) and phase angle (φ in rad), allowing mechanical characterization of the stiffness and fluidity properties of the pancreas. Forty patients with untreated PDAC and 33 patients with untreated AIP who underwent diagnostic pancreatic MRI at 3-T together with multifrequency MR elastography and tomoelastography data processing were prospectively enrolled. Ten healthy volunteers served as controls. Two radiologists and a technician measured pancreatic stiffness and fluidity independently. The two radiologists also independently evaluated the patients' conventional MR sequences using the following diagnostic score: 1, definitely PDAC; 2, probably PDAC; 3, indeterminate; 4, probably AIP; and 5, definitely AIP. Interobserver agreement was assessed. Stiffness and fluidity of PDAC, AIP, and healthy pancreas, as well as diagnostic performance of tomoelastography and conventional MRI, were compared.

RESULTS

AIP showed significantly lower stiffness and fluidity than PDAC and significantly higher stiffness and fluidity than healthy pancreas. Pancreatic fluidity was not influenced by secondary obstructive changes. The intraclass correlation coefficient for pancreatic stiffness and fluidity by the 3 readers was near-perfect (0.951-0.979, all p < 0.001). Both stiffness and fluidity allowed distinguishing PDAC from AIP. AUCs were 0.906 for stiffness, 0.872 for fluidity, and 0.842 for conventional MRI.

CONCLUSIONS

Pancreatic stiffness and fluidity both allow differentiation of PDAC and AIP with high accuracy.

KEY POINTS

• AIP showed significantly lower stiffness and fluidity than PDAC and significantly higher stiffness and fluidity than healthy pancreas. • Both stiffness and fluidity allowed distinguishing PDAC from AIP. • Pancreatic fluidity could distinguish malignancy from non-malignant secondary obstructive changes.

Clinical and imaging findings suggestive of histopathological immunoglobulin G4-related disease: a single-center retrospective study

OBJECTIVE

To investigate the clinical and imaging features predicting the histopathological diagnosis of immunoglobulin G4 (IgG4)-related disease (IgG4RD) in patients with suspected IgG4RD on computed tomography (CT).

METHODS

We retrospectively reviewed the medical records of 178 patients with CT findings suspicious of IgG4RD from January 2015 to December 2017. Patients who underwent tissue biopsy were included to evaluate the association between patient characteristics and histopathological diagnosis of IgG4RD. The histopathological diagnosis was classified into IgG4RD and non-IgG4RD. Clinical, laboratory, and imaging features were compared between patients with IgG4RD and non-IgG4RD, and logistic regression analysis was performed to identify the predictors for histopathologically confirmed IgG4RD.

RESULTS

Of the 103 patients with histopathologically proven diseases, 46 and 57 patients were classified as IgG4RD and non-IgG4RD, respectively. The median age was 64 years; 65% of patients were male. There were significant differences in sex (P = 0.035), fever (P = 0.039), serum IgG4 level (P < 0.001), renal involvement (P = 0.036), lacrimal or salivary glands involvement (P = 0.050), swelling pattern on CT (P = 0.001), and positron emission tomography (PET)-CT findings (P < 0.001) between patients with IgG4RD and non-IgG4RD. Multivariate analysis revealed elevated IgG4 level > 135 mg/dL (odds ratio [OR] = 5.418, P < 0.001), kidney involvement (OR = 6.170, P = 0.044), and the swelling feature on CT (OR = 4.301, P = 0.012) to be independent factors for histopathological diagnosis of IgG4RD.

CONCLUSION

This study suggests that elevated IgG4 level, renal involvement, and swelling pattern on CT are associated with histopathological diagnosis of IgG4RD. The clinical and imaging features might help to decide further evaluation in patients with clinically suspected IgG4RD. Key Points • Computed tomography (CT) is not sufficient to discriminate between IgG4-related disease (IgG4RD) and non-IgG4RD conditions. • Histopathological diagnosis of IgG4RD is associated with elevated IgG4 level, renal involvement, and swelling pattern on CT. • Positron emission tomography-CT may be a useful diagnostic tool in patients with clinically suspected IgG4RD. >.