Autoimmune pancreatitis

Eosinophilic pancreatitis: a review of the pathophysiology, diagnosis, and treatment

Eosinophilic pancreatitis (EP) is an extremely rare disease caused by purely eosinophilic infiltration of the pancreas. EP is prone to being misdiagnosed as pancreatic cancer, causing unnecessary economic and physical harm to the patient. We report three cases of EP that were cured by steroids without relapse from 2017 to now. The clinical data of the three patients, including clinical manifestations, serological manifestations, imaging (ultrasound, computed tomography, and MRI), pathological diagnosis and treatment, and telephone follow-up of all patients, were retrospectively analysed. In addition, a literature search was conducted on the Web of Science and PubMed databases using key terms related to EP, considering case reports with no restrictions on the date of publication or language. In conclusion, we analysed 19 cases and determined the diagnostic criteria for EP. The diagnostic algorithm for EP can be used to diagnose EP easily. We hope that our standards and algorithm can reduce the rate of misdiagnosis and contribute to clinical diagnosis and treatment. In addition, we expect to evaluate more EP cases to test our diagnostic criteria and design a systematic diagnostic flow chart.

ACVIM consensus statement on pancreatitis in cats

Background

Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges.

Objective

To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field.

Animals

None.

Methods

A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations.

Results

There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats.

Conclusions and Clinical Importance

Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.

The Clinicopathologic Spectrum of IgG4-Related Disease

Immunoglobulin G4-related disease is a fibroinflammatory systemic disease that is characterized by focal or diffuse organ infiltration by immunoglobulin G4-bearing plasma cells. Immunoglobulin G4-related disease may affect any organ, and a high index of suspicion is necessary for early detection to avoid irreversible fibrosis, organ dysfunction, and death. Tumor-forming lesions are common radiological features of immunoglobulin G4-related disease that need to be differentiated from malignancies. The diagnostic approach requires the integration of clinical, biochemical, and radiographic manifestations with classic histopathologic features, which remain crucial to diagnosis. The histology of immunoglobulin G4-related disease is determined by a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis in the presence of increased immunoglobulin G4-positve plasma cells. Although immunoglobulin G4-related disease forms a distinct, clinically independent disease category, many questions and problems remain unanswered, especially on its pathogenesis and the role of immunoglobulin G4. Advances in the understanding of immunoglobulin G4-related disease are likely to change the diagnostic approach in the future and create potential targets for therapeutic purposes. Here we describe the concept of immunoglobulin G4-related disease and the most recent knowledge in the clinico-pathological characteristics on this emerging disease. This study can guide clinicians in early diagnosis and prevent unnecessary surgical resections.

Autoimmune pancreatitis: Imaging features

Background and Objectives

Autoimmune pancreatitis (AIP) remains a difficult disease to diagnose before treatment, particularly if presenting as a focal mass lesion. The purpose of this multicenter retrospective study is to analyze imaging features of histologically confirmed AIP to determine the additional diagnostic value of contrast-enhanced ultrasound (CEUS), contrast-enhanced endoscopic ultrasound (CE-EUS), and elastography to B-mode features.

Patients and Methods

We report on a retrospective data collection of 60 histologically confirmed cases of AIP in comparison to 16 patients with pancreatic adenocarcinomas (PDAC). All CE (-E) US examinations were assessed by two independent readers in consensus. The role of CEUS and CE-EUS for pancreatic evaluation was defined according to the 2011 European Federation of Societies for Ultrasound in Medicine and Biology guidelines.

Results

After injection of ultrasound (US) contrast agents, most AIP lesions displayed focal or diffuse isoenhancement (86.6%) in the arterial phase, while most of the PDAC lesions (93.7%) were hypoenhancing (P < 0.01). During the late phase, most AIP lesions were hyper-(65%) or iso-enhancing (35%), while most PDAC lesions were hypoenhancing (93.7%). CE-EUS was performed in a subset of ten patients and showed hyperenhancement in all AIP cases. Most focal AIP lesions (n = 27, 79.4%) were stiffer than the surrounding pancreatic parenchyma.

Conclusions

In this study, percutaneous and endoscopic contrast enhanced harmonic US techniques consistently revealed diffuse and focal types of AIP to have features consistent with vascularized lesions. Differentiation from the typically hypovascularized pancreatic adenocarcinoma was possible with CE (-E) US evaluation.

Ultrasound imaging features of isolated pancreatic tuberculosis

Background and Objectives:

Isolated pancreatic tuberculosis (PTB) is extremely rare worldwide. The purpose of this multicenter retrospective study is to analyze imaging features of histologically confirmed isolated PTB in order to determine the diagnostic features of the new methods contrast enhanced ultrasound (CEUS), ultrasound elastography and contrast enhanced endoscopic ultrasound (CE-EUS).

Patients and Methods:

We report on a retrospective data collection of 12 cases of PTB confirmed by histology or cytology. All examinations were interpreted by two independent readers in consensus. CEUS, CE-EUS and ultrasound elastography were performed according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines.

Results:

In PTB patients the common bile duct was never dilated. Multiple retroperitoneal lymph nodes are the second important B-mode ultrasound feature detected in 75% of PTB patients. CE-EUS was performed in three PTB patients demonstrating hyperenhancement. On elastography, all PTB lesions were markedly stiffer than surrounding pancreatic parenchyma.

Conclusions:

Here we report the first time on CEUS and elastography features of PTB. PTB had some typical imaging features with iso- or hyperenhancement on CE(E) US. PTB is markedly stiffer on elastography. If clinicians are aware of clinical features of PTB and conduct appropriate investigations with multiple modalities including B-mode ultrasound, CEUS, and EUS guided fine needle aspiration, diagnosis of PTB without laparotomy is possible and the disease can be effectively treated with anti-tuberculous drugs.

Pancreatic duct stenosis: Differential diagnosis between malignant and benign conditions at secretin-enhanced MRCP

PURPOSE

To define imaging criteria of benign and malignant nature in patients with main pancreatic duct (MPD) stenosis.

MATERIALS-METHODS

S-MRCPs of 35 patients with pancreatitis and 14 with adenocarcinoma were evaluated.

RESULTS

Adenocarcinoma caused higher prevalence of complete stenosis (14/14-100% vs 17/35-49%), dilated side-branches (14/14-100% vs 18/35-51%) and lower prevalence of duct-penetrating sign (0/14-0% vs 31/35-89%). The number of stenoses was higher in benign conditions (mean 1.4 Vs 1). Upstream MPD diameter was higher in cancer-induced stenoses (4.5 vs 2.9mm).

CONCLUSIONS

Single complete stenosis with dilated side branches, increased MPD caliber and absent duct-penetrating sign are suggestive of malignancy.

Pancreatic duct abnormalities in focal autoimmune pancreatitis: MR/MRCP imaging findings

AIM

To evaluate the magnetic resonance (MR) imaging-MR cholangiopancreatographic (MRCP) findings of focal forms of autoimmune pancreatitis (AIP) to describe ductal involvement at diagnosis.

METHODS

MR examinations of 123 patients affected by AIP were analysed. We included 26 patients who satisfied International Consensus Diagnostic Criteria and were suffering from focal AIP. Image analysis included: site of parenchymal enlargement, main pancreatic duct (MPD) diameter, MPD stenosis, stricture length, presence of upstream dilation within the stricture, signal intensity, and pancreatic enhancement.

RESULTS

Signal intensity abnormalities were localized in the head in 10/26 (38.5%) and in the body-tail in 16/26 (61.5%) patients. MRCP showed a single MPD stenosis in 12/26 (46.1%) and multiple MPD stenosis in 14/26 (53.8%) patients, without a dilation of the upstream MPD (mean: 3.83 mm). Lesions showed hypointensity on T1-weighted images in all patients, and hyperintensity on T2-weighted images in 22/26 (84.6%) patients. The affected parenchyma was hypovascular during the arterial phase in 25/26 (96.2%) patients with contrast retention.

CONCLUSIONS

MR-MRCP are effective techniques for the diagnosis of AIP showing the loss of the physiological lobulation and the typical contrastographic appearance. The presence of multiple, long stenoses without an upstream MPD dilation at MRCP suggests the diagnosis of AIP, and can be useful in differential diagnosis of pancreatic adenocarcinoma.

KEY POINTS

• MRI represents the gold standard in the diagnosis of AIP. • MRCP is an increasingly useful technique in the diagnosis of focal AIP. • MRCP could be a problem-solving tool in the differential diagnosis of AIP.

Autoimmune pancreatitis: Multimodality non-invasive imaging diagnosis

Autoimmune pancreatitis (AIP) is characterized by obstructive jaundice, a dramatic clinical response to steroids and pathologically by a lymphoplasmacytic infiltrate, with or without a pancreatic mass. Type 1 AIP is the pancreatic manifestation of an IgG4-related systemic disease and is characterized by elevated IgG4 serum levels, infiltration of IgG4-positive plasma cells and extrapancreatic lesions. Type 2 AIP usually has none or very few IgG4-positive plasma cells, no serum IgG4 elevation and appears to be a pancreas-specific disorder without extrapancreatic involvement. AIP is diagnosed in approximately 2%-6% of patients that undergo pancreatic resection for suspected pancreatic cancer. There are three patterns of autoimmune pancreatitis: diffuse disease is the most common type, with a diffuse, “sausage-like” pancreatic enlargement with sharp margins and loss of the lobular contours; focal disease is less common and manifests as a focal mass, often within the pancreatic head, mimicking a pancreatic malignancy. Multifocal involvement can also occur. In this paper we describe the features of AIP at ultrasonography, computed tomography, magnetic resonance and positron emission tomography/computed tomography imaging, focusing on diagnosis and differential diagnosis with pancreatic ductal adenocarcinoma. It is of utmost importance to make an early correct differential diagnosis between these two diseases in order to identify the optimal therapeutic strategy and to avoid unnecessary laparotomy or pancreatic resection in AIP patients. Non-invasive imaging plays also an important role in therapy monitoring, in follow-up and in early identification of disease recurrence.

Autoimmune pancreatitis: multidetector-row computed tomography (MDCT) and magnetic resonance (MR) findings in the Italian experience

Multidetector-row computed tomography (MDCT) and magnetic resonance (MR) imaging are currently the most frequently performed imaging modalities for the study of pancreatic disease. In cases of suspected autoimmune pancreatitis (AIP), a dynamic quadriphasic (precontrast, contrast-enhanced pancreatic, venous and late phases) study is recommended in both techniques. In the diffuse form of autoimmune pancreatitis (DAIP), the pancreatic parenchyma shows diffuse enlargement and appears, during the MDCT and MR contrast-enhanced pancreatic phase, diffusely hypodense and hypointense, respectively, compared to the spleen because of lymphoplasmacytic infiltration and pancreatic fibrosis. During the venous phase of MDCT and MR imaging, the parenchyma appears hyperdense and hyperintense, respectively, in comparison to the pancreatic phase. In the delayed phase of both imaging modalities, it shows retention of contrast media. A "capsule-like rim" may be recognised as a peripancreatic MDCT hyperdense and MR hypointense halo in the T2-weighted images, compared to the parenchyma. DAIP must be differentiated from non-necrotizing acute pancreatitis (NNAP) and lymphoma since both diseases show diffuse enlargement of the pancreatic parenchyma. The differential diagnosis is clinically difficult, and dynamic contrast-enhanced MDCT has an important role. In the focal form of autoimmune pancreatitis (FAIP), the parenchyma shows segmental enlargement involving the head, the body-tail or the tail, with the same contrast pattern as the diffuse form on both modalities. FAIP needs to be differentiated from pancreatic adenocarcinoma to avoid unnecessary surgical procedures, since both diseases have similar clinical and imaging presentation. The differential diagnosis is clinically difficult, and dynamic contrast-enhanced MDCT and MR imaging both have an important role. MR cholangiopancreatography helps in the differential diagnosis. Furthermore, MDCT and MR imaging can identify the extrapancreatic manifestations of AIP, most commonly biliary, renal and retroperitoneal. Finally, in all cases of uncertain diagnosis, MDCT and/or MR follow-up after short-term treatment (2-3 weeks) with high-dose steroids can identify a significant reduction in size of the pancreatic parenchyma and, in FAIP, normalisation of the calibre of the upstream main pancreatic duct.

Clinical and Immunopathologic Profile of Mexican Patients with IgG4 Autoimmune Pancreatitis

Autoimmune pancreatitis is part of the spectrum of IgG4-associated diseases. Its diagnostic criteria and histological subtypes have been formally proposed recently and although based on current data it has been suggested that there are differences in clinical presentation among populations, more research is needed to properly establish if this heterogeneity exists. In this paper, we describe 15 cases of autoimmune pancreatitis diagnosed at a Mexican centre of reference, all of them associated to the lymphoplasmocytic sclerosing pancreatitis variant. The mean age at the onset of symptoms was 47.5 ± 14.4 years, and 53% of patients were male. The main manifestations were weight loss (87%), obstructive jaundice (53%), and acute (27%) and chronic (27%) pancreatitis. Only 20% of patients had high IgG4 serum levels at the time of diagnosis. All patients receiving prednisone responded favourably, both in their pancreatic and extrapancreatic manifestations. Clinical manifestations of Mexican patients showed certain differences with respect to those usually reported.

Approach to a patient with elevated serum alkaline phosphatase

Cholestasis develops either from a defect in bile synthesis, impairment in bile secretion, or obstruction to bile flow, and is characterized by an elevated serum alkaline phosphatase and gamma-glutamyltransferase disproportionate to elevation of aminotransferase enzymes. Key elements to the diagnostic workup include visualization of the biliary tree by cholangiography and evaluation of liver histology. The hope is that recent advances in understanding the genetic factors and immune mechanisms involved in the pathogenesis of cholestasis will lead to newer therapeutic interventions in the treatment of these diseases.

Diagnosis and management of autoimmune pancreatitis

• AIP is a heterogeneous disease with two distinct subtypes, now called type 1 and type 2. The proportions of these subtypes vary in their distribution worldwide. • Pancreatic cancer is the leading differential diagnosis for AIP, although AIP can mimic any other major pancreatobiliary disease. • Cross-sectional abdominal imaging CT/MRI should form the cornerstone to the diagnosis of AIP. • Serum IgG4 provides collateral evidence for the diagnosis of AIP and should not be the sole basis for the diagnosis. False-positive elevation in serum IgG4 can be seen in up to 10% of patients with pancreatic cancer. • A steroid trial should be performed only in select situations after ruling out pancreatic cancer and by gastroenterologists experienced in treating AIP. • Disease recurrence can be seen in up to 40% of patients after initial steroid therapy.

Hepatopancreatobiliary manifestations of inflammatory bowel disease

Inflammatory bowel disease (IBD) is frequently associated with extraintestinal manifestations such as hepatopancreatobiliary manifestations (HPBMs), which include primary sclerosing cholangitis (PSC), pancreatitis, and cholelithiasis. PSC is correlated with IBD, particularly ulcerative colitis (UC); 70-80% of PSC patients in Western countries and 20-30% in Japan have comorbid UC. Therefore, patients diagnosed with PSC should be screened for UC by total colonoscopy. While symptoms of PSC-associated UC are usually milder than PSC-negative UC, these patients have a higher risk of colorectal cancer, particularly in the proximal colon. Therefore, regular colonoscopy surveillance is required regardless of UC symptoms. Administration of 5-aminosalicylic acid or ursodeoxycholic acid may prevent colorectal cancer and cholangiocarcinoma. While PSC is diagnosed by diffuse multifocal strictures on cholangiography, it must be carefully differentiated from immunoglobulin G4 (IgG4)-associated cholangitis, which shows a similar cholangiogram but requires different treatment. When PSC is suspected despite a normal cholangiogram, the patient may have small-duct PSC, which requires a liver biopsy. IBD patients have a high incidence of acute and chronic pancreatitis. Most cases are induced by cholelithiasis or medication, although some patients may have autoimmune pancreatitis (AIP), most commonly type 2 without elevation of serum IgG4. AIP should be accurately identified based on characteristic image findings, because AIP responds well to corticosteroids. Crohn's disease is frequently associated with gallstones, and several risk factors are indicated. HPBMs may influence the management of IBD, therefore, accurate diagnosis and an appropriate therapeutic strategy are important, as treatment depends upon the type of HPBM.