A practical approach to the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis is a disease characterized by specific pathological features,different from those of other forms of pancreatitis,that responds dramatically to steroid therapy.The pancreatic parenchyma may be diffusely or focally involved with the possibility of a low-density mass being present at imaging,mimicking pancreatic cancer.Clinically,the most relevant problems lie in the diagnosis of autoimmune pancreatitis and in distinguishing autoimmune pancreatitis from pancreatic cancer.Since in the presence of a pancreatic mass the probability of tumour is much higher than that of pancreatitis,the physician should be aware that in focal autoimmune pancreatitis the first step before using steroids is to exclude pancreatic adenocarcinoma.In this review,we briefly analyse the strategies to be followed for a correct diagnosis of autoimmune pancreatitis.

Diagnostic yield of EUS-FNA of small(≤15 mm) solid pancreatic lesions using a 25-gauge needle

Background: Early detection of small solid pancreatic lesions is increasingly common. To date, few and contradictory data have been published about the relationship between lesion size and endoscopic ultrasound-guided fine needle aspiration(EUS-FNA) diagnostic yield. The aim of this study was to assess the relation between the size of solid pancreatic lesions and the diagnostic yield of EUS-FNA using a 25-gauge needle in a center without available rapid on-site evaluation.Methods: In the retrospective cohort study, we selected patients who underwent EUS-FNA for solid pancreatic lesions with a 25-gauge needle from October 2014 to October 2015. Patients were divided into three groups(≤15 mm, 16–25 mm and >25 mm), and the outcomes were compared.Results: We analyzed 163 patients. Overall adequacy, sensitivity, specificity and accuracy were 85.2%,81.8%, 93.7%, and 80.4%, respectively. When stratified by size, the sensitivity and accuracy correlated with size(P = 0.016 and P = 0.042, respectively). Multivariate analysis showed that lesion size was the only independent factor(P = 0.019, OR = 4.76) affecting accuracy. The role of size as an independent factor affecting accuracy was confirmed in a separate multivariate analysis, where size was included in the model as a covariate(P = 0.018, OR = 1.08).Conclusion: Our study demonstrates that, in the absence of rapid on-site evaluation, mass size affects the accuracy of EUS-FNA of solid pancreatic lesions.

Comparison of imaging-based and pathological dimensions in pancreatic neuroendocrine tumors

AIM To establish the ability of magnetic resonance(MR) and computer tomography(CT) to predict pathologic dimensions of pancreatic neuroendocrine tumors(Pan NET) in a caseload of a tertiary referral center.METHODS Patients submitted to surgery for Pan NET at the Surgical Unit of the Pancreas Institute with at least 1 preoperative imaging examination(MR or CT scan) from January 2005 to December 2015 were included and data retrospectively collected. Exclusion criteria were: multifocal lesions, genetic syndromes, microadenomas or mixed tumors, metastatic disease and neoadjuvant therapy. Bland-Altman(BA) and Mountain-Plot(MP) statistics were used to compare size measured by each modality with the pathology size. Passing-Bablok(PB) regression analysis was used to check the agreement between MR and CT.RESULTS Our study population consisted of 292 patients. Seventy-nine(27.1%) were functioning Pan NET. The mean biases were 0.17 ± 7.99 mm, 1 ± 8.51 mm and 0.23 ± 9 mm, 1.2 ± 9.8 mm for MR and CT, considering the overall population and the subgroup of non-functioning-Pan NET, respectively. Limits of agreement(LOA) included the vast majority of observations, indicating a good agreement between imaging and pathology. The MP further confirmed this finding and showed that the two methods are unbiased with respect to each other. Considering ≤ 2 cm non-functioning-Pan NET, no statistical significance was found in the size estimation rate of MR and CT(P = 0.433). PBR analysis did not reveal significant differences between MR, CT and pathology.CONCLUSION MR and CT scan are accurate and interchangeable imaging techniques in predicting pathologic dimensions of Pan NET.

Autoimmune pancreatitis not otherwise specified(NOS): Clinical features and outcomes of the forgotten type

Background:Autoimmune pancreatitis(AIP)is a well-recognized fibroinflammatory disease of the pancreas.Despite the significant number of studies published on AIP type 1 and 2,no studies have been focused on AIP type not otherwise specified(NOS)and therefore very little is known about clinical features and long-term outcomes of these patients.The aim of this study was to investigate clinical and radiological features of AIP type NOS-patients.Methods:Patients classified as AIP type NOS at clinical onset included in our database prospectively maintained since 1995 were evaluated.Epidemiological,clinical data were collected and analyzed.Results:Forty-six patients were included in the study.The clinical onset was mainly characterized by weight loss,jaundice and acute pancreatitis.Eight patients(17.4%)were reclassified as AIP type 2 during follow-up because of the development of ulcerative colitis.Seven patients(15.2%)experienced relapse after steroid treatment but only one(2.2%)needed immunosuppressive drugs because of recurrent relapses.Conclusions:AIP type NOS shares clinical features similar to AIP type 2 and a relevant proportion of patients was reclassified as AIP type 2 during follow-up because of the development of ulcerative colitis.The risk of relapse is low but not irrelevant.