Immunoglobulin G4 -related gastrointestinal disease associated with type 1 autoimmune pancreatitis: A case report.

Immunoglobulin G4 (IgG4)-related diseaseis a systemic inflammatory condition of unknown etiology characterized by increases in serum IgG4 and in the number of IgG4-positive cells in affected tissues. One of the commonly involved locations is the pancreas; this condition is known as type 1 autoimmune pancreatitis (AIP). Type 1 AIP, which shows a biliary stricture in the intrapancreatic bile duct, can be misdiagnosed as a malignancy due to similar cholangiography findings and clinical presentation. In rare cases complicated by post-bulbar duodenal ulcers, differentiating between type 1 AIP and malignancies is even more difficult. An 81-year-old male was referred to our hospital for the treatment of a pancreatic head mass and obstructive jaundice. Serological and radiological findings were consistent with both type 1 AIP and a malignancy. Gastroduodenoscopy revealed a post-bulbar duodenal ulcer with endoscopic features that evoked malignant duodenal invasion. Although biopsies were negative for malignant cells, subsequent bleeding from the lesion suggested the progression of malignancy, which led to surgical resection. Pancreatoduodenectomy and pathological examination indicated that type 1 AIP was present. Simultaneously, the involvement of IgG4-related disease in the ulcerative lesion was suggested. To our knowledge, this is the first reported case of type 1 AIP complicated by post-bulbar duodenal ulcers, which was misdiagnosed as malignancy and considered an IgG4-related gastrointestinal disease associated with type 1 AIP.

Pancreatic infiltrative malignancy masquerading as autoimmune pancreatitis: Case report, review of radiological criteria, and literature.

We report a case of a 44-year-old male patient, who presented to the University Hospital of Salzburg, Austria with abdominal pain, persistent jaundice, and lack of appetite. Radiological work-up (CT, MRI, PET/CT) indicated a suspicious mass of the uncinate process of the pancreatic head with adjacent infiltration and regional lymphadenopathy. The differential diagnosis was between primary pancreatic cancer and focal autoimmune pancreatitis. Further laparoscopic biopsies from multiple areas, showed only fibrous scarring processes, with no malignancy. Treatment with steroids didn't give any benefits. After multiple follow-up CTs and MRs within 6 months-additional biopsies were done, which eventually demonstrated adenocarcinoma. Evidently the cancer diagnosis was much delayed and the patient started receiving chemotherapy, but radical surgery was not possible. Multiple articles and case reports can be found in the literature, that are reviewing the fact that pancreatic inflammatory processes are mimicking pancreatic tumor, but not many articles or case reports are available in the literature, where neoplastic processes are misinterpreted as inflammatory and incorrectly proven with histological examination. One of the main reasons for improper diagnosis is the desmoplastic reaction around the pancreatic malignancy. Another important aspect is the acceptance of histological diagnosis as conclusive, where no opposing arguments are specified, based on radiological criteria.

A case of ulcerative colitis with a variety of autoimmune diseases including ankylosing spondylitis, type 2 autoimmune pancreatitis, and primary sclerosing cholangitis.

Ankylosing spondylitis (AS), primary sclerosing cholangitis (PSC), and autoimmune pancreatitis (AIP) are known as extraintestinal manifestations (EIMs) of ulcerative colitis (UC). A 74-year-old Japanese man visited our hospital because of white stool. He had been diagnosed with AS when he was 30 years old, and he was HLA-B27-positive. Based on various examination results, it was suspected that AIP had caused bile duct stricture. During the clinical course, he was diagnosed with UC and PSC. Then, AIP was diagnosed because he had localized pancreatic enlargement, irregular stenosis of the main pancreatic duct, PSC, and no tumor cells of pancreas. A patient with all four of these diseases, AS, AIP, PSC, and UC, is very rare. Therefore, we report a quite rare case with three EIMs (AS, PSC, and AIP) of UC.

A suspected case of serum IgG4-negative type 1 autoimmune pancreatitis detected due to localized pancreatic duct narrowing: a case report.

A 50-year-old woman was referred to our hospital with elevated serum amylase levels. Physical examination revealed no jaundice or abdominal tenderness. Serum IgG4 was negative. Computed tomography revealed a localized pancreatic duct narrowing in the pancreatic head, with caudal pancreatic duct dilation and an intraductal papillary mucinous neoplasm. Pancreatic enlargement was not observed. Endoscopic ultrasonography (EUS) showed a small hypoechoic mass. Although EUS-guided, fine-needle aspiration was performed, no diagnosis was established. Endoscopic retrograde pancreatography showed a localized narrowing in the main pancreatic duct of the pancreatic head. A biopsy of the narrowing was performed through the minor papilla because of difficult access from the major papilla. The specimen showed the infiltration of numerous IgG4-positive plasma cells, suggesting type 1 autoimmune pancreatitis (AIP). Six months later, magnetic resonance cholangiopancreatography revealed improvement in the narrowing without specific treatment. The patient presented with localized narrowing of the pancreatic duct and caudal duct dilation, which was distinct from pancreatic cancer. Diagnostic difficulties arose from negative serum IgG4 results, the lack of typical imaging characteristics of AIP, and failure to meet the AIP criteria according to the relevant Japanese and international guidelines. However, AIP was suspected and surgery was successfully avoided through a biopsy.

Pancreatico-renal fistula associated with pancreatic cysts caused by type 1 autoimmune pancreatitis.

To our best knowledge, the formation of a pancreatico-renal fistula and the presence of pancreatic fluid collection in the renal subcapsular space have not been reported as autoimmune pancreatitis (AIP) complications. We describe a case of a pancreatico-renal fistula associated with type 1 AIP. The patient presented with abdominal and back pain accompanied by pancreatic cystic lesions during an untreated course of AIP. The diagnosis of pancreatico-renal fistula was based on the presence of a left renal subcapsular fluid collection containing pancreatic amylase, disappearance of pancreatic cysts, and a defect in the partial anterior renal fascia observed on imaging studies. Treatment with steroids and percutaneous drainage resulted in improvement. Pancreatic pseudocysts can affect other organs owing to their digestive action. Similar symptoms may occur in patients with AIP.

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.

The effect of steroid therapy on pancreatic exocrine function in autoimmune pancreatitis.

BACKGROUND/OBJECTIVES: Autoimmune pancreatitis (AIP) is a steroid-responsive inflammatory disease of the pancreas. Few studies investigated pancreatic exocrine function (PEF) in patients suffering from AIP and no definitive data are available on the effect of steroids in PEF recovery. Aim of the study is the evaluation of severe pancreatic insufficiency (sPEI) prevalence in AIP at clinical onset and after steroid treatment. METHODS: 312 Patients with diagnosis of AIP between January 1st, 2010 and December 31st, 2020 were identified in our prospectively maintained register. Patients with a pre-steroid treatment dosage of fecal elastase-1 (FE-1) were included. Changes in PEF were evaluated in patients with available pre- and post-treatment FE (between 3 and 12 months after steroid). RESULTS: One-hundred-twenty-four patients were included, with a median FE-1 of 122 (Q1-Q3: 15-379) µg/g at baseline. Fifty-nine (47.6 %) had sPEI (FE-1<100 µg/g). Univariable analysis identified type 1 AIP, radiological involvement of the head of the pancreas (diffuse involvement of the pancreas or focal involvement of the head), weight loss, age and diabetes as associated with a greater risk of sPEI. However, at multivariable analysis, only the involvement of the head of the pancreas was identified as independent risk factor for sPEI. After steroids, mean FE-1 changed from 64 (15-340) to 202 (40-387) µg/g (P = 0.058) and head involvement was the only predictor of improvement of sPEI. CONCLUSION: The inflammatory involvement of the head of the pancreas is associated with PEF severity, as well as PEF improvement after treatment with steroids in patients with AIP.

Diagnostic performance of F-18 FDG PET/CT in differentiating autoimmune pancreatitis from pancreatic cancer: a systemic review and meta-analysis.

OBJECTIVES: This study aims to evaluate the utility of F-18 FDG PET/CT in the non-invasive diagnosis of autoimmune pancreatitis (AIP) and differentiating it from pancreatic cancer (CaP) based on the amount and pattern of FDG uptake, as well as involvement of extra-pancreatic sites. METHODS: A systematic search was conducted using PubMed, Scopus, Cochrane Library and Google Scholar. Only those studies that compared the findings of F-18 FDG PET/CT in terms of SUVmax, pattern of FDG uptake and presence of FDG-avid extra-pancreatic sites in both AIP and CaP were included. Studies were qualitatively assessed for risk of bias and publication bias. The diagnostic performance of parameters on PET/CT was examined through pooled sensitivity, specificity, diagnostic odd's ratio (DOR) and summary receiver operator characteristic (SROC) curve analysis. RESULTS: Six studies were included with a total of 580 patients. 178 patients had AIP (Age 18-90 years, male, M: female, F ratio-8.4:1) and 402 patients had CaP (Age 22-88 years, M:F ratio-1.5:1). Type of AIP was reported in only 3 studies, with the included cases predominantly being type 1 AIP. All studies were retrospective with heterogeneity and a risk on patient selection and index test. The FDG uptake, expressed as SUVmax, was lower in AIP with a weighted mean difference of -3.11 (95% confidence interval, CI: -5.28 to -0.94). To diagnose AIP, the pooled sensitivity, specificity and DOR of diffuse pattern of FDG uptake were 0.59 (95% CI: 0.51-0.66), 0.89 (95% CI: 0.86-0.92) and 21.07 (95% CI: 5.07-88.32), respectively, with an area under curve (AUC) of 0.717 on SROC analysis. The pooled sensitivity, specificity and DOR of FDG-avid extra pancreatic sites were 0.55 (95% CI: 0.45-0.65), 0.58 (95% CI: 0.52-0.64) and 2.33 (95% CI: 1.40-3.89), respectively, with an AUC of 0.632. CONCLUSION: On F-18 FDG PET/CT, a pancreatic lesion of AIP has a lower SUVmax value than CaP. A diffuse pattern of FDG uptake and presence of an extra-pancreatic FDG-avid site are nearly 21 times and twice more likely in AIP than CaP, respectively.

A prospective study on the histological evaluation of type 1 autoimmune pancreatitis using endoscopic ultrasound-guided fine needle biopsy with a 19-gauge Franseen needle.

BACKGROUND/PURPOSE: To assess the diagnostic efficacy and safety of endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a 19-gauge Franseen needle for autoimmune pancreatitis (AIP). METHODS: Twenty patients suspected of having type 1 AIP were prospectively enrolled and underwent EUS-FNB with a 19-gauge Franseen needle. Their data were compared with those of historical controls: a total of 29 type 1 AIP patients had EUS-FNB with a 22-gauge Franseen needle. RESULTS: Specimens suitable for histological evaluation were obtained from 19 of the 20 patients (95%), and the median total tissue area was 11.9 mm2. The histological diagnosis rate of AIP was 65% (95% CI: 43.2%-82%). Adverse events were observed in three patients (15%), and a switch to 22-gauge needles occurred during transduodenal puncture in two patients. Compared to those punctured with 22-gauge needles, patients punctured with 19-gauge needles had greater prevalence of each characteristic feature of lymphoplasmacytic sclerosing pancreatitis, but the difference was not statistically significant. CONCLUSIONS: EUS-FNB using a 19-gauge Franseen needle demonstrated favorable performance for the histological diagnosis of AIP and allowed for large tissue samples, potentially facilitating pathological diagnosis. However, during transduodenal puncture, maneuverability is reduced; therefore, the needle may need to be selected according to the puncture site.

Immunoglobulin G4-related Autoimmune Pancreatitis and Hypopituitarism Following Immune Checkpoint Inhibitor Therapy: A Case Report.

A 70-year-old man underwent nephrectomy for renal cell carcinoma followed by 3 cycles of pembrolizumab as adjuvant chemotherapy. Three months later, he complained of appetite loss. He was diagnosed with secondary adrenal insufficiency and pancreatic tumor. Amylase and immunoglobulin G (IgG) 4 levels were normal. The differential diagnosis poses challenges in distinguishing pancreatic cancer, renal cell carcinoma metastasis, and autoimmune pancreatitis, necessitating tumor resection surgery. A histological examination revealed IgG4-related sclerosing pancreatitis. Postoperatively, there was no recurrence of pancreatitis. It is essential to consider the potential development of IgG4-related diseases after the administration of immune checkpoint inhibitors.

Type one autoimmune pancreatitis based on clinical diagnosis: A case report.

BACKGROUND: Autoimmune pancreatitis (AIP) is a rare form of autoimmune-mediated pancreatitis, which is easily misdiagnosed as pancreatic cancer and thus treated surgically. We studied the diagnosis and treatment of a patient with type 1 AIP recently admitted to our hospital, and reviewed the literature to provide a reference for clinical diagnosis of AIP. CASE SUMMARY: The chief complaint was yellowing of the body, eyes and urine for 21 d. The patient's clinical presentation was obstructive jaundice and imaging suggested pancreatic swelling. It was difficult to distinguish between inflammation and tumor. Serum immunoglobulin G4 (IgG4) was markedly elevated. IgG4 is an important serological marker for type 1 AIP. The patient was diagnosed with AIP, IgG4-related cholangitis, acute cholecystitis and hepatic impairment. After applying hormonal therapy, the patient's symptoms improved significantly. At the same time, imaging suggested that pancreatic swelling subsided, and liver function and other biochemical indicators decreased. The treatment was effective. CONCLUSION: In patients with pancreatic swelling, the possibility of AIP should be considered.

Recent advances in IgG4-related autoimmune pancreatitis.

The incidence of IgG4-related autoimmune pancreatitis (IgG4-AIP) is high in Asia and other countries, and unnecessary treatment is often undertaken due to both missed diagnosis and misdiagnosis in clinical practice. Although IgG4-AIP has attracted increasing attention, the details of IgG4-AIP pathogenesis and systemic immune response, including its relationship to tumor pathogenesis, are still unclear. In recent years, research on serum immunological detection, pathological features, clinical manifestations, diagnosis and treatment measures for IgG4-AIP has gradually increased. It is of great importance to summarize and discuss the latest progress regarding IgG4-AIP disease.

Recurrent acute pancreatitis: a harbinger for irreversible chronic pancreatitis.

Recurrent acute pancreatitis is beginning to be recognized as an intermediary stage in the continuous spectrum between acute and chronic pancreatitis. It is crucial to identify this disease stage and intervene with diagnostic and therapeutic modalities to prevent the painful and irreversible condition of chronic pancreatitis. We review the recent advances in diagnosing and managing this important 'call for action' condition.

Understanding autoimmune pancreatitis: Clinical features, management challenges, and association with malignancies.

In this editorial we comment on the article by Jaber et al. Autoimmune pancreatitis (AIP) represents a distinct form of pancreatitis, categorized into AIP-1 and AIP-2, characterized by obstructive jaundice, lymphoplasmacytic infiltrate, and fibrosis. AIP-1, associated with elevated immunoglobulin G4 (IgG4) levels, exhibits higher relapse rates, affecting older males, while AIP-2 is less common and linked to inflammatory bowel disease. AIP is considered a manifestation of IgG4-related systemic disease, sharing characteristic histological findings. Steroids are the primary treatment, with emerging biomarkers like interferon alpha and interleukin-33. AIP poses an increased risk of various malignancies, and the association with pancreatic cancer is debated. Surgery is reserved for severe cases, necessitating careful evaluation due to diagnostic challenges. AIP patients may have concurrent PanINs but display favorable long-term outcomes compared to pancreatic cancer patients. Thorough diagnostic assessment, including biopsy and steroid response, is crucial for informed surgical decisions in AIP.

Differentiating localized autoimmune pancreatitis and pancreatic ductal adenocarcinoma using endoscopic ultrasound images with deep learning.

Objectives: Localized autoimmune pancreatitis is difficult to differentiate from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. In recent years, deep learning methods have improved the diagnosis of diseases. Hence, we developed a special cross-validation framework to search for effective methodologies of deep learning in distinguishing autoimmune pancreatitis from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. Methods: Data from 24 patients diagnosed with localized autoimmune pancreatitis (8751 images) and 61 patients diagnosed with pancreatic ductal adenocarcinoma (20,584 images) were collected from 2016 to 2022. We applied transfer learning to a convolutional neural network called ResNet152, together with our innovative imaging method contributing to data augmentation and temporal data process. We divided patients into five groups according to different factors for 5-fold cross-validation, where the ordered and balanced datasets were created for the performance evaluations. Results: ResNet152 surpassed the endoscopists in all evaluation metrics with almost all datasets. Interestingly, when the dataset is balanced according to the factor of the endoscopists' diagnostic accuracy, the area under the receiver operating characteristic curve and accuracy were highest at 0.85 and 0.80, respectively. Conclusions: It is deduced that image features useful for ResNet152 correlate with those used by endoscopists for their diagnoses. This finding may contribute to sample-efficient dataset preparation to train convolutional neural networks for endoscopic ultrasonography-imaging diagnosis.

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.

Association of autoimmune pancreatitis and intraductal papillary mucinous neoplasm. A retrospective analysis from a tertiary care referral center.

BACKGROUND: Autoimmune Pancreatitis (AIP) is a rare chronic inflammatory disease affecting the pancreas. Chronic pancreatic inflammation represents a risk factor for pre-neoplastic conditions such as Intraductal Papillary Mucinous Neoplasia (IPMN). Due to the rarity of AIP, the incidence, and clinical features of IPMN occurring in AIP patients remains unknown. AIMS: In the present study we aimed to explore the relationship between AIP and IPMN and to characterize the clinical features and outcomes of IPMN occurring in the context of AIP. METHODS: We retrospectively (2008-2020) analyzed the clinical and radiological records of a large single center cohort of patients with AIP and investigated the prevalence of IPMN. We then compared the clinical, laboratory and radiological characteristics of patients with IPMN and AIP with a cohort of patients with isolated IPMN. RESULTS: Five hundred and nineteen patients were included in this retrospective study. Sixteen patients had concomitant IPMN and AIP(3%); 61 patients had isolated AIP (12%); 442 patients had isolated IPMN (85%). The prevalence of IPMN in patients with AIP was higher than that observed in the general population (21%vs8-10%). Worrisome Features and High-Risk Stigmata were more frequently observed in IPMN occurring together with AIP compared to isolated IPMN(p < 0.05). Based on radiological features IPMN in the context of AIP was more frequently of main-duct type compared to isolated IPMN(p < 0.05). CONCLUSION: Our data suggest that AIP represents a chronic inflammatory condition that might favor IPMN development with high-risk features. Prolonged surveillance of these patients and longitudinal studies are required to further test the association with AIP and malignant and pre-malignant conditions.

Pancreatic Ductal Adenocarcinoma Encapsulated by a Tumor-Forming Type 1 Autoimmune Pancreatitis Located at the Pancreatic Tail: A Case Report.

Introduction: Autoimmune pancreatitis (AIP) is recognized as a disease with a good prognosis that responds well to steroids, but the complication of pancreatic ductal adenocarcinoma (PDAC) in AIP is a rare condition. We report a case of PDAC encapsulated by tumor-forming type 1 AIP. Case Presentation: The patient, a 65-year-old female, was found to have high CA19-9 levels and a pancreatic mass with a diameter of 30 mm on abdominal ultrasonography. Contrast-enhanced computed tomography revealed a 40-mm mass in the tail of the pancreas that had a 27-mm oligemic mass inside it. From these work-up examinations, this tumor was diagnosed as PDAC, with evidence of colonic invasion. As curative resection for PDAC, a distal pancreatectomy with splenectomy and combined colon resection were performed. Histopathological examination showed invasive PDAC surrounded by IgG4-positive plasma cell infiltration. Based on these findings, a diagnosis was made of PDAC located in the pancreatic tail capsulized by type 1 AIP. The postoperative course was uneventful, and the patient was discharged on postoperative day 15. She underwent postoperative adjuvant chemotherapy with S-1 for 6 months, and no recurrence was noted for 2 years after operation. Conclusion: Currently, there are two hypothetical mechanisms of PDAC induction by AIP: (1) carcinogenic stimulation due to chronic inflammation and (2) paraneoplastic syndrome caused by AIP. Further study of the relationship between AIP and pancreatic cancer is needed, and follow-up should be conducted while keeping in mind the possibility of complications.