Diagnosis Of Autoimmune Pancreatitis Research Articles

The Diagnostic Challenges of Autoimmune Pancreatitis – A Case Report

Purpose: Autoimmune pancreatitis (AIP) is a fibro-inflammatory disease that accounts for 4,6–5,0% of chronic pancreatitis and encompasses two entities, one related to a systemic disease referred to as IgG4-related disease (type 1 AIP) and the other generally without immunoglobulin G4-positive cells and without systemic involvement (type 2 AIP). Its association to other autoimmune diseases, namely ulcerative colitis, is known although the exact relationship between the two entities is not completely clarified. The diagnosis of autoimmune pancreatitis requires a multidisciplinary approach. Due to overlap in clinical and radiological features, it is often misdiagnosed as pancreatic cancer. Methods and Aims: This clinical case report describes an uncommon entity highlighting the challenge in the diagnostic approach of a pancreatic mass. Results: A 45-year-old female, with a medical history of ulcerative colitis and arterial hypertension treated with bisoprolol and mesalazine, underwent an abdominal computerized tomography scan (CT scan) for study of a solid liver lesion, which incidentally revealed a tail pancreatic mass. There were no symptoms at all and physical examination was normal. Laboratory analyses showed normal levels of immunoglobulin G4 and negative antinuclear antibodies. Endoscopic ultrasound revealed a homogeneous and hypoechogenic lesion in the pancreatic tail with a “sausage-like” appearance. Endoscopic ultrasound-guided fine needle aspiration was inconclusive (pancreatic adenocarcinoma hypothesis could not be excluded) and the patient underwent a laparoscopic distal pancreatectomy. Histopathology examination confirmed the diagnosis of a type 2 autoimmune pancreatitis. At 12-month follow-up, the patient remained asymptomatic with no evidence of recurrence. Conclusions: The diagnosis of AIP is a clinical challenge, not only due to its rarity, but also due to the need of integrating clinical, laboratory, imaging, and histology data for confirmation. Although the diffuse form of AIP can be easily distinguished from pancreatic cancer on imaging, differentiating focal AIP from pancreatic malignancy is challenging, so a surgical approach is often proposed. The association of AIP with other autoimmune illnesses can be identified in more than half of the cases. Among these, the association with inflammatory bowel disease, and more specifically with ulcerative colitis, has been described being the most common.

Diagnostic and therapeutic considerations in biopsy-proven type 2 autoimmune pancreatitis: comparative analysis with biopsy-proven type 1 autoimmune pancreatitis.

Autoimmune processes are now an increasingly recognized cause of acute and chronic pancreatitis. Autoimmune pancreatitis is a rare, benign pathology with two distinct clinicopathologic subtypes. The aim of this study was to compare the presentation, diagnostic considerations and outcomes of patients with biopsy-proven type 1 and 2 autoimmune pancreatitis (AIP). A retrospective review of the Queensland Health pathology database of histologically proven AIP was conducted. Parameters compared included demographics, diagnostic criterion and post-treatment outcomes. Twenty-three patients had a confirmed histological diagnosis of AIP (type 1=13, type 2=10). Patients with type 2 AIP were younger (median age 49 versus 59 years, P< 0.05). There was no significant difference in gender distribution of disease at presentation. Type 2 AIP presented with significant increased focal pancreatic changes on cross-sectional imaging (80% versus 54%, P< 0.05). Serum IgG4 levels were raised (>1.40 g/L) in 69% of patients with type 1 AIP and not detected in type 2 (P< 0.01). Concurrent underlying inflammatory bowel disease was present in a higher proportion of type 2 AIP (40% versus 15%, P< 0.05). A significantly increased proportion of patients with type 2 AIP underwent surgical resection (70% versus 30%, P< 0.05). Conservative management was utilized in more patients with type 1 disease (54% versus 30%). On follow-up, two patients have experienced symptomatic relapse at 6-18 months. Diagnostic challenges do exist and clinicians must suspect 2 type AIP in young, serum IgG4-negative inflammatory bowel disease patients with recurrent pancreatitis.

The Diagnosis of Autoimmune Pancreatitis Using Endoscopic Ultrasonography.

Autoimmune pancreatitis (AIP) is characterized by enlargement of the pancreas and irregular narrowing of the main pancreatic duct. It is often associated with IgG4-related sclerosing cholangitis (IgG4-SC), in which the bile duct narrows. Although characteristic irregular narrowing of the pancreatic duct caused by endoscopic retrograde cholangiopancreatography is noted in AIP, it is difficult to differentiate between localized AIP and pancreatic carcinoma based on imaging of the pancreatic duct. While stenosis of the bile duct in IgG4-SC is characterized by longer-length stenosis than in cholangiocarcinoma, differentiation based on bile duct imaging alone is challenging. Endoscopic ultrasound (EUS) can characterize hypoechoic enlargement of the pancreas or bile duct wall thickening in AIP and IgG4-SC, and diagnosis using elastography and contrast-enhanced EUS are being evaluated. The utility of EUS-guided fine needle aspiration for the histological diagnosis of AIP has been reported and is expected to improve diagnostic performance for AIP. Findings in the bile duct wall from endoscopic retrograde cholangiopancreatography followed by intraductal ultrasonography are useful in differentiating IgG4-SC from cholangiocarcinoma. Diagnoses based on endoscopic ultrasonography play a central role in the diagnosis of AIP.

Case Report: Painless obstructive jaundice caused by IgG4 autoimmune pancreatitis; the role of endoscopic ultrasound in diagnosis

We report the case of a 60-year-old woman, presenting with painless obstructive jaundice of unknown etiology, who was finally found to suffer from type I autoimmune pancreatitis (AIP). This case emphasizes AIP as a rare cause in the differential diagnosis of obstructive jaundice and the role of endoscopic ultrasound (EUS) in final diagnosis, which is difficult to establish. According to diagnostic criteria, we combined the results from serologic, imaging and histological features (specifically lgG4 levels, computed tomography, magnetic resonance imaging/magnetic resonance cholangiopancreatography and EUS) with cytological results, leading to a final diagnosis. Our patient’s response to corticosteroids was impressive, confirming the diagnosis, leading to complete remission of the disease. Whilst diagnosis of AIP is challenging, the application of diagnostic criteria can lead to correct diagnosis. Therapy is corticosteroid based, with very satisfying outcomes.

Endoscopic ultrasound-guided fine needle aspiration versus biopsy for diagnosis of autoimmune pancreatitis: Systematic review and comparative meta-analysis.

Endoscopic ultrasound (EUS) is recommended for guiding the acquisition of pancreatic tissue in patients with suspected autoimmune pancreatitis (AIP). Data comparing EUS-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) sampling in the diagnosis of AIP are limited. A comprehensive literature search of the PubMed, EMBASE, and Ovid MEDLINE databases was conducted until April 2020. The pooled rates of diagnostic yield for the histologic criteria of AIP, histologic tissue procurement, and adverse events were compared between FNA and FNB. Diagnostic yields were also compared between 19 gauge (G) and 22G needles. This meta-analysis included nine studies comprising 309 patients with AIP who underwent FNA and seven studies comprising 131 patients who underwent FNB. The pooled diagnostic yields for level 1 or 2 histology criteria of AIP were 55.8% (95% confidence interval (CI) 37.0-73.9%, I2 =91.1) for FNA and 87.2% (95% CI 68.8-98.1%, I2 =69.4) for FNB (P=0.030). The pooled histologic procurement rates for FNA and FNB were 91.3% (95% CI, 84.9-97.6%, I2 =82.9) and 87.0% (95% CI, 77.8-96.1%, I2 =40.0), respectively (P=0.501). Adverse events were comparable between two groups. When analyzed by needle size, the diagnostic yield was better with a 19G needle than with a 22G needle (88.9% vs. 60.6%, P=0.023). The diagnostic yield may be better with FNB needles than with FNA needles for the diagnosis of AIP, despite the similar rate of histologic tissue procurement. A quantitative definition for the histologic sample adequacy for AIP may be warranted.

Role of Endoscopic Ultrasonography-Guided Fine Needle Aspiration/Biopsy in the Diagnosis of Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP) is histologically characterized by lymphoplasmacytic sclerosing pancreatitis (LPSP). Recently, the diagnostic yield of endoscopic ultrasonography-guided fine needle aspiration/biopsy (EUS-FNA/B) for AIP has been reported. However, its role in the diagnostic flow of AIP is not fully elucidated. We retrospectively reviewed 53 consecutive patients who were suspected with AIP and underwent EUS-FNA/B. We evaluated the contribution of EUS-FNA/B to the diagnosis of AIP before considering response to steroid therapy among patients with diffuse enlargement of the pancreas and those with focal enlargement, respectively. Twenty-two patients showed diffuse pancreatic enlargement and 31 showed focal enlargement. The final diagnosis was definitive AIP in 32 patients, probable AIP in 2, possible AIP in 1, and mass-forming focal pancreatitis in 18. There was no change in diagnosis after EUS-FNA/B among patients with diffuse pancreatic enlargement, while diagnosis changed in 38.7% (12/31) among those with focal enlargement—there was a probable to definitive diagnosis in 4 patients, unspecified to definitive in 3, and unspecified to probable in 5. EUS-FNB provided a significantly higher sensitivity for typical pathological findings of LPSP than EUS-FNA, and 10 patients were diagnosed as pathologically definitive AIP by EUS-FNB, though none were by EUS-FNA (p = 0.002). EUS-FNA/B was useful in the diagnosis of focal type AIP, and steroid therapy could be introduced after the diagnosis was confirmed. Meanwhile, EUS-FNA/B provided no contribution to diagnosis of diffuse type AIP. EUS-FNB showed a higher diagnostic yield than FNA.

CT, MRI and PET/CT features of abdominal manifestations of cutaneous melanoma: a review of current concepts in the era of tumor-specific therapies.

Abdominal manifestations in patients with cutaneous melanoma include involvement due to metastatic spread and immune checkpoint inhibitor induced adverse events. The purpose of this review is to provide a critical overview of abdominal manifestations in patients with cutaneous melanoma and highlight the current imaging challenges in the era of tumor-specific therapies. Immune checkpoint inhibitors represent a treatment with demonstrated efficacy in the treatment of advanced cutaneous melanoma but are associated with several abdominal adverse events that must be recognized. CT has a role in the identification of colitis, enteritis and pancreatitis, whereas MRI has an important role in the diagnosis of autoimmune pancreatitis. Current evidence demonstrates that MRI should be the preferred imaging technique for the detection and characterization of hepatic and splenic metastases from cutaneous melanoma. The role of 18F-FDG-PET/CT should be further evaluated but current literature suggests an efficacy in the detection of pancreatic metastases not seen on CT and MRI.

Pancreatic solid focal lesions: autoimmune pancreatitis or pancreatic cancer?

Purpose: The diagnosis of pancreatic ductal adenocarcinoma (PDAC) in treatable early stages continues to be challenging. Autoimmune pancreatitis (AIP) can, similarly to PDAC, present as a focal mass and, therefore, an accurate differential diagnosis is of crucial importance. Raised serum immunoglobulin G4 (IgG4) levels, over the twice the normal value, are considered to be one of the significant diagnostic features of type 1 AIP. However, IgG4 can also be increased in patients with PDAC, but levels usually do not exceed twice the normal value. Materials and methods: In the years 2012 - 2018, IgG4 serum levels were examined in 117 patients with histologically confirmed PDAC. Histological resection specimens or bioptic specimens were taken from the pancreatic lesions of patients with both PDAC and an elevated IgG4 level (above 135mg/dL). These were then tested for the presence of IgG4 and plasmocytes in the pancreatic tissue, and changes characteristic for type 1 AIP were also searched for. Results: In 14/117 PDAC patients (11.9 %) the plasmatic IgG4 levels were higher than 135 mg/dL. In 2 patients (1.7 %) the serum IgG4 levels were more than double the normal value, and thus suggestive of AIP according to the guidelines. Of these two patients - one of them met the histological criteria for diagnosis of AIP in the simultaneous presence of PDAC. Conclusions: Differentiating AIP from PDAC can be sometimes problematic since these diseases can both present as focal pancreatic mass/ lesions. IgG4 has been considered useful for AIP diagnosis, however, IgG4 levels can be slightly elevated, as is the case with PDAC. IgG4 levels of over the twice of the upper limit are rare among PDAC patients (1.7% in our study group). However, cases of simultaneous presentation of PDAC and AIP have been documented and should not be neglected. Therefore, targeted biopsy of the pancreas is the method of choice in cases suspected of being a focal form of AIP, and we recommend it over other modalities, such as e.g. response to steroid therapy.

The use of immunohistochemistry for IgG4 in the diagnosis of autoimmune pancreatitis: A systematic review and meta-analysis

BackgroundThe diagnosis of autoimmune pancreatitis (AIP) remains challenging, especially when serum IgG4 is normal or imaging features are indeterminate. We performed a systematic review and meta-analysis to evaluate the performance of IgG4 immunostaining of pancreatic, biliary, and ampullary tissues as a diagnostic aid for AIP. MethodsA comprehensive literature search of the PubMed, EMBASE, and Ovid MEDLINE databases was conducted until February 2020. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. A random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy. ResultsThe meta-analysis included 20 studies comprising 346 patients with AIP and 590 patients with other pancreatobiliary diseases, including 371 pancreatobiliary malignancies. The summary estimates for tissue IgG4 in discriminating AIP and controls were as follows: diagnostic odds ratio 38.86 (95% confidence interval (CI), 18.70–80.75); sensitivity 0.64 (95% CI, 0.59–0.69); specificity 0.93 (95% CI, 0.91–0.95). The area under the curve was 0.939 for tissue IgG4 in discriminating AIP and controls. Subgroup analysis revealed no significant difference in diagnostic accuracy according to control groups (pancreatobiliary cancer versus other chronic pancreatitis) and sampling site (pancreas versus bile duct/ampulla). ConclusionsCurrent data demonstrate that IgG4 immunostaining of pancreatic, biliary, and ampullary tissue has a high specificity but moderate sensitivity for diagnosing AIP. IgG4 immunostaining may be useful in supporting a diagnosis of AIP when AIP is clinically suspected, but a combination of imaging and serology does not provide a conclusive diagnosis.

S3330 Autoimmune Pancreatitis Masquerading as Peritoneal Carcinomatosis

INTRODUCTION: Autoimmune pancreatitis (AIP) accounts for approximately 2% of cases of chronic pancreatitis. Type 1 AIP or IgG4 related pancreatitis can present in an acute, recurrent or chronic setting and can have a variety of presentations. In 60-90% of IgG4 related disease, multiple organ systems are involved concurrently. AIP should be considered in all patients with pancreatitis of unclear etiology due to the spectrum of presentation of IgG4 related illness. CASE DESCRIPTION/METHODS: 59-year-old Polish female visiting family in the United States with a history of colon cancer status post right hemicolectomy in Poland 2 years prior to admission who presented with nausea and vomiting. Her symptoms, lipase elevation and CT findings confirmed a diagnosis of pancreatitis. She denied alcohol use and gallstones were not seen on imaging. CT scan was significant for multilobulated pancreatic necrosis with abscesses. Endoscopic ultrasound evaluation showed necrosis without a window for drainage. She then underwent IR guided aspiration of a pancreatic abscess with drain placement and was initiated on IV antibiotics due to concern for infection. In the absence of etiology for her pancreatitis, immunoglobulin labs were sent to evaluate for possible autoimmune etiology. Additionally, imaging also revealed nodularities in the peritoneum concerning for carcinomatosis, which was concerning for possible malignancy given her past history of colon cancer. Tumor markers were within normal limits. IR biopsy of omental nodularity showed fibroadipose tissue with fibrosis, fat necrosis and chronic inflammation. Immunostain was negative for carcinoma. IgG levels came back elevated at IgG4 224 suggesting AIP with possible peritoneal related IgG4 systemic disease. Biopsies were then stained for IgG4 antibodies but were without significant signs of IgG4. Repeat imaging showed no change in pancreatic necrosis/abscess despite daily drain output and antibiotics. A diagnosis of AIP with IgG4 systemic disease was favored and prednisone was started with plans for outpatient follow-up and repeat CT scan. DISCUSSION: AIP is a rare cause of pancreatitis that can present in a variety of ways and can even demonstrate systemic manifestations. Consideration of AIP is important since this is one of the few known treatable etiologies. In conclusion, AIP should be entertained in patients when common causes of pancreatitis have been excluded and signs of systemic disease are noted.

Prevalence of histological features resembling autoimmune pancreatitis in neoplastic pancreas resections.

Types 1 and 2 autoimmune pancreatitis (AIP) can mimic pancreatic neoplasia. Due to the small quantity of tissue in mass-targeted pancreas biopsies, inflammatory features may raise the differential of AIP. However, the frequency of AIP-like histology in neoplastic pancreas is not well characterised. Therefore, the specificity of inflammatory lesions on biopsy with respect to the diagnosis of AIP is uncertain. Neoplastic pancreas resections performed at our institution between 2008 and 2019 were retrospectively reviewed. Features of AIP types 1 and 2 were assessed in the non-neoplastic areas. If features of immunoglobulin (Ig)G4-associated AIP were seen, IgG4 immunohistochemistry was performed. We identified 163 neoplastic pancreas resections. Of these, 34 had one or more types of inflammatory lesions in non-neoplastic pancreatic tissue. Dense lymphoplasmacytic inflammation mimicking type 1 AIP was found in six cases with mild to moderately increased IgG4-positive plasma cells. Neutrophilic infiltrates in small intralobular ducts were found in 20 cases. Mild extralobular ductitis or duct microabscess was found in 10 specimens. Marked neutrophilic duct destruction that resembled granulocytic epithelial lesions was found in 12 cases. Some cases showed multiple features. Approximately 20% of neoplastic pancreas resections showed focal areas that could raise the differential of AIP. More cases showed neutrophilic predominant inflammation as seen in type 2 autoimmune pancreatitis, compared to dense lymphoplasmacytic infiltrates seen in type 1 AIP. Pathologists must be cautious when making a diagnosis of AIP on biopsy tissue based on histological findings alone.

Corticosteroids prevent the progression of autoimmune pancreatitis to chronic pancreatitis

Background/objectivesPatients with autoimmune pancreatitis (AIP) sometimes progress to chronic pancreatitis (CP). We evaluated the ability of corticosteroids to prevent the progression to CP. MethodsWe defined patients with definitive findings of CP (stones in the main pancreatic duct [MPD] or multiple pancreatic calcifications) as having severe calcification (SC). A total of 145 AIP patients were enrolled. We measured the duration between AIP diagnosis and SC development and retrospectively compared the time to SC development between patients with and without steroids. Multivariate analysis for factors associated with SC were performed. ResultsNineteen (13%) patients progressed to SC. Since 95 patients had pancreatic head swelling and SC was found in these patients only, our analysis focused mainly on these at-risk populations. In Kaplan-Meier analysis limited to patients with pancreatic head swelling, the incidence of SC was significantly lower in patients with steroids than in those without (hazard ratio [HR] 0.18, 95% confidence interval [CI] 0.07–0.52; p < 0.001). Multivariate testing of patients with pancreatic head swelling confirmed that steroid therapy was significantly associated with a lower incidence of SC (HR 0.11, 95% CI 0.03–0.34; p < 0.001), while MPD dilation at AIP diagnosis was related to a higher incidence of SC (HR 4.02, 95% CI 1.43–11.7; p = 0.009). ConclusionsCorticosteroids appeared to prevent progression to CP in AIP patients, especially in those with pancreatic head swelling. Patients with both pancreatic head swelling and MPD dilation at diagnosis have a higher incidence of progression to CP. Steroid therapy is suggested for these high-risk cases.

Management of autoimmune pancreatitis

The article contains modern data on such a chronic pancreatic disease as autoimmune pancreatitis (AIP). Statistical data on the prevalence and incidence of AIP are presented, the current international classification of this pathology is considered, the main features of type 1 AIP (lymphoplasmacytic sclerosing pancreatitis, LPSP) and type 2 AIP (idiopathic duct centric pancreatitis, IDCP) are put forward. The clinical manifestation of these types is different: obstructive jaundice develops more often in patients with LPSP, while patients with IDCP mostly have acute pancreatitis. The presence and variety of extrapancreatic manifestations of the disease with extremely frequent concomitant development of ulcerative colitis is emphasized. The features of serological diagnosis of AIP and the role of IgG4 level in determining the type of disease are considered. The proper techniques of AIP instrumental diagnostics are listed, the typical changes detected during computed tomography and the distinctive histological characteristics of LPSP and IDCP are considered. The feasibility of a differential diagnosis between AIP and pancreatic cancer is indicated by analyzing the results of serological, imaging, and histological studies. The algorithm of management of AIP patients depending on the type of disease is described, as well as the tactics of prescribing corticosteroids, immunomodulators upon LPSP and IDCP. Immunomodulators of choice (mycophenolate mofetil, azathioprine) are indicated, and rituximab administration features are considered. Possible signs of AI recurrence are listed (IgG4-sclerosing cholangitis, high IgE level).

Risks and characteristics of pancreatic cancer and pancreatic relapse in autoimmune pancreatitis patients.

We examined the differences in the risks and characteristics of pancreatic relapse (PR) and pancreatic cancer (PC) in patients with autoimmune pancreatitis (AIP). We retrospectively reviewed 123 type 1 AIP patients with a median follow-up of 55months (interquartile range, 27-98). The following items were evaluated: (i) cumulative relapse rates and risk factors, (ii) the incidence of PC, (iii) PR versus PC, and (iv) outcomes after the appearance of morphological changes in the pancreas (focal enlargement, apparent mass lesions, or main pancreatic duct dilation). (i) The cumulative PR rates were 1.7% within 1year, 11.5% within 3years, and 22.6% within 5years. Lack of maintenance therapy, IgG4-related sclerosing cholangitis, and IgG4-related kidney disease were identified as independent predictors of relapse. (ii) Two patients (1.6%) were diagnosed with PC at 17 and 22months after initial AIP diagnosis. (iii) Thirteen (59.1%) and four (18.2%) patients with PR had focal enlargement and main pancreatic duct dilation, respectively. The median CA19-9 level at initial diagnosis was significantly higher in PC patients (21 vs 220.5U/mL, P=0.014). (iv) Eight PR patients underwent endoscopic ultrasound-guided fine-needle aspiration, none of whom had malignant findings. PC was diagnosed by ultrasound-guided fine-needle aspiration in both cancer patients. Although the incidence of PC is low, it may mimic PR in AIP patients. Surveillance is important, and when morphological changes occur, biopsy and evaluation of serum IgG4 and CA19-9 levels (particularly if the levels were high before) should be considered.

Differentiation of Focal-Type Autoimmune Pancreatitis From Pancreatic Ductal Adenocarcinoma Using Radiomics Based on Multiphasic Computed Tomography.

The aim of this study was to develop a radiomics model for a differential diagnosis of focal-type autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma. A total of 96 patients, 45 with AIP and 51 with pancreatic ductal adenocarcinoma, were retrospectively evaluated. All patients underwent pretreatment abdominal computed tomography imaging acquired at noncontrast, arterial, and venous phases. Furthermore, 1160 radiomics features were extracted from each phasic image to build radiomics models. The performance of radiomics model was evaluated by sensitivity, specificity, and accuracy. The results of radiomics model were also compared with those of radiologists' visual assessments. The sensitivity, specificity, and accuracy of the optimal radiomics model were 93.3%, 96.1%, and 94.8%, respectively. They were higher than those of the radiologists' assessments with sensitivity of 57.78% and 73.33%, specificity of 88.24% and 90.20%, and accuracy of 75.00% and 81.25%, respectively. Radiomics is helpful for a differential diagnosis of AIP in clinical practice as a noninvasive and quantitative method.

Multicentric Italian survey on daily practice for autoimmune pancreatitis: Clinical data, diagnosis, treatment, and evolution toward pancreatic insufficiency.

Autoimmune pancreatitis (AIP) is a rare, and relatively new, form of chronic pancreatitis. The management of AIP can vary considerably among different centres in daily clinical practice. The aim of this study is to present a picture of epidemiological, clinical characteristics, outcomes, and the real-life practice in terms of management in several academic and non-academic centres in Italy. Data on the clinical presentation, diagnostic work-up, treatments, frequency of relapses, and long-term outcomes were retrospectively collected in a cohort of AIP patients diagnosed at 14 centres in Italy. One hundred and six patients were classified as type 1 AIP, 48 as type 2 AIP, and 19 as not otherwise specified. Epidemiological, clinical, radiological, and serological characteristics, and relapses were similar to those previously reported for different types of AIP. Endoscopic cytohistology was available in 46.2% of cases, and diagnostic for AIP in only 35.2%. Steroid trial to aid diagnosis was administered in 43.3% cases, and effective in 93.3%. Steroid therapy was used in 70.5% of cases, and effective in 92.6% of patients. Maintenance therapy with low dose of steroid (MST) was prescribed in 25.4% of cases at a mean dose of 5 (±1.4) mg/die, and median time of MST was 60 days. Immunosuppressive drugs were rarely used (10.9%), and rituximab in 1.7%. Faecal elastase-1 was evaluated in only 31.2% of patients, and was pathological in 59.2%. In this cohort of AIP patients, diagnosis and classification for subtype was frequently possible, confirming the different characteristics of AIP1 and AIP2 previously reported. Nevertheless, we observed a low use of histology and steroid trial for a diagnosis of AIP. Steroid treatment was the most used therapy in our cohort. Immunosuppressants and rituximab were rarely used. The evaluation of exocrine pancreatic insufficiency is underemployed considering its high prevalence.

Endoscopic Ultrasound–Guided Core Biopsy for Diagnosis of Autoimmune Pancreatitis

Once thought to be rare, autoimmune pancreatitis (AIP) is now recognized as one of the more common etiologies of acute pancreatitis. However, the

High-Dose Prednisone for Treatment of Autoimmune Pancreatitis in a Patient with Coronavirus Disease 2019 (COVID-19) due to Infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Patient: Male, 53-year-oldFinal Diagnosis: Autoimmune pancreatitis type 1 • COVID-19Symptoms: Abdominal and/or epigastric pain • feverMedication: —Clinical Procedure: —Specialty: Gastroenterology and Hepatology • Infectious DiseasesObjective:Unusual clinical courseBackground:Autoimmune pancreatitis (AIP) is a rare, steroid-responsive disease of the pancreas. Concurrent treatment with immunosuppressants, including corticosteroids, increases the risk of developing a severe form of coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The World Health Organization (WHO) advises against the use of corticosteroids in patients with SARS-CoV-2 due to their poor outcomes in patients with SARS-CoV and Middle East respiratory syndrome (MERS-CoV), unless these patients require steroid treatment for a coexisting disease.Case Report:A 53-year old patient was admitted with symptoms and diagnostic findings consistent with AIP. Thorough etiological workup revealed an elevated IgG4 level of 361 mg/dL and significant clinical response to corticosteroid treatment, leading to a diagnosis of AIP. After finishing steroid treatment at home, the patient was readmitted with another episode of AIP complicated by development of acute necrotic collection and COVID-19 while taking a second course of high dose prednisone. The patient was continued on high dose prednisone, started on azathioprine and intravenous meropenem, and underwent CT guided percutaneous drainage. He also received supportive care for COVID-19. After significant clinical improvement, the patient was discharged to quarantine at home, which he completed uneventfully.Conclusions:Despite the use of corticosteroids due to AIP, this high risk patient recovered from COVID-19 without complications. These findings support the use of corticosteroids when necessary for treatment of coexisting conditions in COVID-19 patients.

Sa1462 FEASIBILITY, SAFETY, AND DIAGNOSTIC YIELD OF ENDOSCOPIC ULTRASOUND (EUS)-GUIDED FINE NEEDLE CORE BIOPSY FOR NON-FOCAL, BENIGN, PANCREATIC PARENCHYMAL DISEASES

Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is a well-established method for specimen acquisition in suspected pancreatic malignancies. However, the role of EUS-FNA for, non-focal, non-neoplastic, benign pancreatic diseases such as chronic pancreatitis and autoimmune pancreatitis is diminished by the sample inadequacy and architectural distortion. This is evaded by histologic core biopsies obtained through newer generation EUS-fine needle biopsy (EUS-FNB). This pilot study aimed to evaluate the feasibility, safety, and diagnostic yield of EUS-FNB for non-focal, benign, pancreatic parenchymal diseases. This is a retrospective analysis of a prospectively collected database of all patients who underwent EUS-FNB for suspected non-focal, benign, parenchymal pancreatic disease at a single tertiary-care referral center from 10/04/2016 to 10/16/2019. We abstracted and analyzed patient demographics, EUS findings, histopathology, clinical management, and follow-up data. A total of 12 EUS-guided FNB were performed using a 22-gauge needle (83.3% (n=10) with Acquire (Boston Scientific, Natick, MA) needle and 2 with SharkCore (Medtronic Corp., Boston, MA) needle) for suspected non-focal, benign, parenchymal pancreatic disease during the study period. Eleven patients (mean age 39.1±20 years; 54% females) were included in this study. Transgastric (87%) or transduodenal (13%) EUS-FNB was successful in all patients (technical success: 100%). The mean number of FNB passes was 1.7 (median 2, range 1-3) (Figure 1). EUS-FNB provided pancreatic tissue cores that were adequate for histopathological diagnosis in all cases. The mean length of the core biopsy specimen obtained was 12±8.1 mm. Histopathologic diagnoses included: chronic pancreatitis in 4 (36.3%) patients, autoimmune pancreatitis (AIP) in 3 (27.3%), and parenchyma with no diagnostic abnormality in the remaining 4 patients (36.3%). Based on the histopathological diagnosis of AIP, 3 patients were treated with steroid therapy with excellent clinical response. No adverse events such as bleeding, perforation, or post-biopsy pancreatitis were observed during median follow-up of 8 months (range, 1-37; mean 15.6±15.5). EUS-guided FNB using the newer generation 22-gauge biopsy needle is a feasible and safe procedure and provides adequate pancreatic tissue specimen (core biopsy) in all cases for histopathological diagnosis of non-focal, benign, pancreatic parenchymal diseases.

Diagnostic imaging guide for autoimmune pancreatitis.

The International Consensus Diagnosis Criteria for autoimmune pancreatitis (AIP) has been published internationally for the diagnosis of AIP. However, since the revisions in 2006 and 2011, the Clinical Diagnostic Criteria for Autoimmune Pancreatitis 2018 have been published. The criteria were revised based the Clinical Diagnostic Criteria 2011, and included descriptions of characteristic imaging findings such as (1) pancreatic enlargement and (2) distinctive narrowing of the main pancreatic duct. In addition, pancreatic duct images obtained by magnetic resonance cholangiopancreatography as well as conventional endoscopic retrograde pancreatography were newly adopted. The guideline explains some characteristic imaging findings, but does not contain descriptions of the imaging methods, such as detailed imaging parameters and optimal timings of dynamic contrast-enhanced computed tomography/magnetic resonance imaging. It is a matter of concern that imaging methods can vary from hospital to hospital. Although other characteristic findings have been reported, these findings were not described in the guideline. The present paper describes the imaging methods for obtaining optimal images and the characteristic imaging findings with the aim of standardizing image quality and improving diagnostic accuracy when radiologists diagnose AIP in actual clinical settings.