Diagnosis of autoimmune pancreatitis by EUS-FNA by using a 22-gauge needle based on the International Consensus Diagnostic Criteria

The history of endoscopic ultrasound-guided fine-needle aspiration: development and progress

Endoscopic ultrasonography (EUS) is an important diagnostic technique to accurately diagnose diseases originating from organs near the gastrointestinal tract. EUS-guided fine-needle aspiration (FNA) has improved the histopathological diagnosis. EUS-FNA has been further developed over a long period of 40 years. The history of the development of endosonographic scopes, ultrasonographic observation systems, puncture needles, and puncture methods will provide a springboard for future development.

Autoimmune pancreatitis type 2 (idiopathic duct-centric pancreatitis): A comprehensive review

Autoimmune pancreatitis (AIP) is an uncommon fibro-inflammatory disorder precipitated by autoimmune/inflammatory reactions. Currently, there are two clinical subtypes of AIP (type 1 [AIP-1] and type 2 [AIP-2]) that correspond to two histologic descriptors (lymphoplasmacytic sclerosing pancreatitis and idiopathic duct-centric pancreatitis, respectively). While our understanding of AIP-1 has evolved considerably over the years, little is known about AIP-2 due to its rarity, often leading to misdiagnosis, delayed treatment, and even unnecessary surgical resection. Compared to AIP-1, AIP-2 exhibits distinct clinical and histologic features. Because AIP-2 is a pancreas-restricted disease without a specific serum marker, the evaluation of histologic features (e.g., granulocytic epithelial lesions) is essential for an accurate diagnosis. Patients with AIP-2 respond well to glucocorticoids, with anti-tumor necrosis factor-alpha antibodies as a promising alternative therapy. The prognosis of AIP-2 is generally favorable and relapse is uncommon. Here, we provide an overview of our current knowledge on the clinical features, diagnosis, therapeutic regimens, prognosis, and putative mechanisms underlying AIP-2. Notably, the diagnostic differentiation between AIP-2, especially the mass-forming/focal type, and pancreatic cancer is important, but challenging. In this regard, endoscopic ultrasound-guided core biopsy has a key role, but novel diagnostic markers and modalities are clearly needed.

Diagnostic Evaluation of Solid Pancreatic Lesions: Endoscopic Ultrasound-Guided Fine Needle Aspiration Versus Percutaneous Ultrasound-Guided Core Needle Biopsy

PURPOSE

The main objective of the present study is to compare the safety, technical success and diagnostic yield of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) versus ultrasound-guided percutaneous core-needle biopsy (US-CNB) in patients with solid pancreatic lesions.

METHODS

This is a retrospective study that involved all patients with a solid pancreatic lesion who underwent EUS-FNA or US-CNB between November 2019 and February 2021. Of all patients, 69 (84.1%) had inoperable malignancy, whereas 13 (15.9%) had chronic pancreatitis. Resectability status was ascertained by computed tomography. All core needle biopsies were performed by the same interventional radiologist via ultrasound guidance with an 18-gauge semi-automatic tru-cut needle. All EUS-FNA procedures were performed by the same gastroenterologist with a 27-gauge EUS-FNA needle. Technical success is defined as if the region of interest is reached and specimen taken from the pancreatic lesion. Diagnostic yield is defined as the procurement of sufficient tissue for pathological examination.

RESULTS

Overall, 52 patients (mean age 58.5 ± 9.8 years) who underwent EUS-FNA and 30 patients (60.1 ± 12.1 years) who underwent US-CNB were included. Solid lesions were most commonly (61.5% in EUS-FNA and 50.0% in US-CNB groups) located in pancreatic head in both groups. Mean size of the lesions was comparable in both groups as well. The technical success was 100% in both groups. In 12 (14.6%) patients, pathology results revealed inadequate sampling (11 × in the EUS-FNA and 1 × in the US-CNB group). The diagnostic yield was significantly higher in US-CNB group than in EUS-FNA group (96.7% vs. 78.8%, respectively, p = 0.048). Of 11 patients in the EUS-FNA with inadequate sampling, pancreatic lesions were located in the pancreatic head in 7 (63.6%). No major complications were observed in neither of the groups. As a minor complication, one case of slight abdominal pain was detected in the EUS-FNA group.

CONCLUSION

Based on the results of the present study, both US-CNB and EUS-FNA appeared safe; however, diagnostic yield in the US-CNB group was significantly higher.

Concomitant Pancreatic Ductal Adenocarcinoma and Type 1 Autoimmune Pancreatitis: A Potential Issue in the Diagnosis of Carcinoma by Endoscopic Ultrasound-guided Fine-needle Biopsy

We herein report a 64-year-old man with concomitant pancreatic ductal adenocarcinoma (PDAC) and type 1 autoimmune pancreatitis (AIP). An endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) from the pancreatic head mass revealed level 2 histology of AIP and atypical glands. We diagnosed definitive focal AIP using the clinical diagnostic criteria. Computed tomography revealed that the pancreatic mass had not been reduced by steroid therapy. Surgery was performed after a histological PDAC diagnosis was made via a transpapillary biliary biopsy. The resected specimen revealed PDAC associated with AIP. It is important to consider the cooccurrence of PDAC and AIP even if the histological diagnosis via an EUS-FNB is AIP.

Challenges for clinicians treating autoimmune pancreatitis: Current perspectives

Autoimmune pancreatitis (AIP) is a rare disease clinically characterized by obstructive jaundice, unintentional weight loss, acute pancreatitis, focal pancreatic mass, and diabetes. AIP is classified into two subtypes - type 1 and type 2 - according to pathological findings, clinical features, and serology test results, but some cases may be defined as type not otherwise in the absence of pathological findings and inflammatory bowel disease. To address the differences in diagnostic criteria by country, standard diagnostic criteria for AIP were proposed in 2011 by an international consensus of expert opinions. Differential diagnosis of AIP from pancreatic ductal adenocarcinoma is important but remains challenging for clinicians. Fortunately, all subtypes of AIP show dramatic response to steroid treatment. This review discusses the current perspectives on the diagnosis and management of AIP in clinical practice.

Neutrophil Infiltration and Acinar-ductal Metaplasia Are the Main Pathological Findings in Pembrolizumab-induced Pancreatitis

The histopathological findings of immune checkpoint inhibitor (ICI)-induced pancreatitis have rarely been reported. A 56-year-old man with squamous cell carcinoma of the lung with bone metastasis was being treated with pembrolizumab, an anti-programmed cell death protein-1 antibody. After 13 doses, he was referred to our department due to pancreatitis. Despite characteristic symptoms of acute pancreatitis, imaging findings were similar to those of autoimmune pancreatitis. However, a histological examination showed neutrophil-based inflammatory cell infiltration and acinar-ductal metaplasia. Immunostaining showed CD8-positive T lymphocyte infiltration. This case revealed the characteristic histopathology of pembrolizumab-induced pancreatitis, which was previously poorly understood.

Utility of Endoscopic Ultrasound-Guided Fine-Needle Aspiration and Biopsy for Histological Diagnosis of Type 2 Autoimmune Pancreatitis

In Japan, type 1 autoimmune pancreatitis (AIP) is the most common type of AIP; type 2 AIP is rare. The aim of this study was to clarify the usefulness of endoscopic ultrasound-guided fine-needle aspiration and biopsy (EUS-FNAB) for the diagnosis of type 2 AIP. We analyzed the tissue specimens of 10 patients with suspected type 2 AIP who underwent EUS-FNAB at our hospital between April 2009 and March 2021 for tissue volume and histopathological diagnostic performance. The male-to-female ratio of the patients was 8:2, and the patient age (mean ± standard deviation) was 35.6 ± 15.5 years. EUS-FNAB provided sufficient tissue volume, with high-power field >10 in eight patients (80.0%). Based on the International Consensus Diagnostic Criteria (ICDC), four patients (40.0%) had histological findings corresponding to ICDC level 1, and five patients (50.0%) had histological findings corresponding to ICDC level 2. The results of this study show that EUS-FNB can be considered an alternative method to resection and core-needle biopsy for the collection of tissue samples of type 2 AIP.

The value of endoscopic ultrasonography for differential diagnosis in obstructive jaundice of the distal common bile duct

INTRODUCTION

Obstructive jaundice is a common clinical disease of great significance; however, diagnosing it according to etiology, especially in patients with distal obstructive jaundice is difficult. The development of endoscopic ultrasonography has improved diagnostic methods. Endoscopic ultrasonography not only improves the accuracy of conventional endoscopic ultrasound technology in etiological diagnosis, but also offers several special endoscopic ultrasound technologies for diagnosing distal obstructive jaundice of the common bile duct. What's more, endoscopic ultrasonography can be used to treat distal obstructive jaundice of common bile duct.

AREAS COVERED

This review discusses the diagnostic value and applications of endoscopic ultrasonography for obstructive jaundice of the distal common bile duct.

EXPERT OPINION

This article summarizes the value of endoscopic ultrasonography in the etiological diagnosis, relevant treatment applications of distal obstructive jaundice and the limitations of endoscopic ultrasonography in some etiologies due to the lack of clear comparison with other imaging methods. We also provide new data for the future research direction of endoscopic ultrasonography in distal obstructive jaundice.

Biopsy diagnosis of type 1 autoimmune pancreatitis: Does it bring a conclusion or confusion?

A biopsy-based diagnosis of type 1 autoimmune pancreatitis (AIP) is now feasible via an endoscopic ultrasound-guided fine-needle biopsy, but there are potential issues to address. The benefits of acquiring large tissue samples include more successful immunostaining for Immunoglobulin G4 and more identifications of storiform fibrosis, obliterative phlebitis, and the ductal lesions of type 1 AIP. However, storiform fibrosis may not be present in all the type 1 AIP lesions. An interobserver agreement study revealed only slight-to-moderate agreement among pathologists diagnosing the histological findings of type 1 AIP. Potential reasons for disagreement are the different time phases of the inflammation (which result in heterogeneous histological pictures), a focal appearance of the typical histological findings, and the different definitions used by pathologists. We have thus devised guidance for diagnosing type 1 AIP based on biopsy tissues. In this guidance, we define each histological finding of type 1 AIP, for example, storiform fibrosis as a swirling arrangement of inflammatory cells, spindle-shaped cells, and delicate collagens as a unit. The necessity of elastic stains for identifying obliterative phlebitis is explained, with examples of mimickers. Another important purpose of a biopsy in type 1 AIP cases is differentiation from pancreatic ductal adenocarcinoma (PDAC). In this situation, acinar-ductal metaplasia observed in type 1 AIP is a mimicker of PDAC and should not be confused. For the resolution of potential disagreements among pathologists, a multi-disciplinary approach with the collaboration of clinicians, radiologists, and pathologists is necessary to avoid confusion.

Concordance of the histological diagnosis of type 1 autoimmune pancreatitis and its distinction from pancreatic ductal adenocarcinoma with endoscopic ultrasound-guided fine needle biopsy specimens: an interobserver agreement study

The histological diagnosis of type 1 autoimmune pancreatitis (AIP) based on the findings obtained by an endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) is feasible, but the diagnostic consistency of this method has not been confirmed. We determined the interobserver agreement among 20 pathologists regarding the diagnosis of type 1 AIP, including the distinction from pancreatic ductal adenocarcinoma (PDAC) using large tissue samples obtained by EUS-FNB. After guidance for diagnosing AIP with biopsy tissues was provided, a round 2 was performed. The median sensitivity and specificity for diagnosing PDAC vs. non-neoplastic diseases were 95.2% and 100%, respectively. In groups of specialists (n = 7) and the generalists (n = 13), Fleiss' к-values increased from 0.886 to 0.958 and from 0.750 to 0.816 in round 2. The concordance was fair or moderate for obliterative phlebitis and storiform fibrosis but slight for ductal lesion of type 1 AIP. Discordant results were due to ambiguous findings and biopsy tissue limitations. Among the specialists, the ratio of cases with perfect agreement regarding the presence of storiform fibrosis increased in round 2, but agreement regarding obliterative phlebitis or ductal lesions was not improved. Although the histological definite diagnosis of type 1 AIP was achieved by most observers in > 60% of the cases, the confidence levels varied. Because some ambiguities exist, the histological diagnostic levels based on the diagnostic criteria of type 1 AIP should not be taken for granted. Guidance is effective for improving accurate PDAC diagnoses (notably by recognizing acinar-ductal metaplasia) and for evaluating storiform fibrosis.

Endoscopic ultrasound-guided pancreatic sampling for the histopathological diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis (AIP), which is characterized by pancreatic enlargement and irregular narrowing of the main pancreatic duct, is difficult to differentiate from malignancy. The irregular narrowing of the pancreatic duct, which can be detected via endoscopic retrograde cholangiopancreatography, is a characteristic feature of AIP; however, distinguishing between localized AIP and pancreatic cancer based on pancreatic duct imaging is difficult. This study overviews the efficacy of endoscopic ultrasound (EUS)-guided pancreatic sampling for the histopathological diagnosis of AIP. Recent enhancements in needle biopsy methodologies and technologies have contributed to improvement in the diagnostic efficacy of this technique. The guidance provided in this study for the histological diagnosis of AIP is anticipated to further advance in the histopathological diagnosis of AIP using EUS-guided pancreatic sampling.

Amendment of the Japanese consensus guidelines for autoimmune pancreatitis, 2020

In response to the latest knowledge and the amendment of the Japanese diagnostic criteria for autoimmune pancreatitis (AIP) in 2018, the Japanese consensus guidelines for managing AIP in 2013 were required to be revised. Three committees [the professional committee for developing clinical questions (CQs) and statements by Japanese specialists; the expert panelist committee for rating statements by the modified Delphi method; and the evaluating committee of moderators] were organized. Twenty specialists in AIP extracted the specific clinical statements from a total of 5218 articles (1963-2019) from a search in PubMed and the Cochrane Library. The professional committee made 14, 9, 5, and 11 CQs and statements for the current concept and diagnosis, extra-pancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded the statements as valid after a two-round modified Delphi approach with individually rating these clinical statements, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid. After evaluation by the moderators, the amendment of the Japanese consensus guidelines for AIP has been proposed in 2020.

Current status of type 1 (IgG4-related) autoimmune pancreatitis

In 1995, Yoshida et al. proposed first the concept of "autoimmune pancreatitis" (AIP). Since then, AIP has been accepted as a new pancreatic inflammatory disease and is now divided two subtypes. Type 1 AIP affected immunoglobulin G4 (IgG4) and implicates the pancreatic manifestation of IgG4-related disease, while type 2 is characterized by neutrophil infiltration and granulocytic epithelial lesions (GEL). Recent research has clarified the clinical and pathophysiological aspects of type 1 AIP, which is more than type 2 among the Japanese population. However, many details remain unclear about the pathogenesis and progression of this disease. In this review, we discuss the current knowledge and recent advances relating to type 1 AIP.

[Alternatives of histological material collection - When and how is histological confirmation by ultrasound (US), computer tomography (CT) or endosonography (EUS) useful?]

Histological classifications of tumorous lesions together with adequate staging are necessary for stage-appropriate and personalized therapies. The indications, technical possibilities, and limitations as well as potential complications of image-guided needle biopsy by ultrasound, computed tomography, and endosonography are described. Which procedure for which organ and which lesion?

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Adverse events of endoscopic ultrasound-guided fine-needle aspiration for histologic diagnosis in Japanese tertiary centers: Multicenter retrospective study

BACKGROUND AND AIMS

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is used for the histopathological diagnosis of any type of gastrointestinal disease. Few adverse events are experienced with this procedure; however, the actual rate of adverse events remains unclear. This study aimed to clarify the current status of cases that experienced adverse events related to the EUS-FNA procedure used for histopathologic diagnoses.

METHODS

A retrospective analysis of cases with EUS-FNA-related adverse events in Japanese tertiary centers was conducted by assessing the following clinical data: basic case information, FNA technique, type of procedural adverse events, and prognosis.

RESULTS

Of the 13,566 EUS-FNA cases overall, the total number of cases in which adverse events related to EUS-FNA occurred was 234. The incidence of EUS-FNA-related adverse events was ~1.7%. Bleeding and pancreatitis cases accounted for ~49.1% and 26.5% of all adverse events, respectively. Bleeding was the most common adverse event with only seven cases requiring blood transfusion. In cases with neuroendocrine tumors, pancreatitis was the most frequent adverse event. Needle tract seeding because of EUS-FNA was observed during the follow-up period in only ~0.1% of cases with pancreatic cancer. There was no mortality because of adverse events caused by EUS-FNA.

CONCLUSIONS

This study revealed that the adverse events-related EUS-FNA for histopathologic diagnoses were not severe conditions, and had low incidence.

Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings

Autoimmune pancreatitis (AIP) is characterized by a tumefactive inflammatory lesion resembling pancreatic carcinoma. Type 1 AIP is a pancreatic manifestation of IgG4-related disease characterized by unique histological features that can be identified on imaging. The capsule-like rim, which is a collar of hypertrophic lesion surrounding the pancreas, consists of lymphoplasmacytic infiltration and fibrosis, and storiform fibrosis is often identified. Hypertrophic lesions of various microscopic architectures such as the ducts, veins (obliterative phlebitis), arteries (periarteritis), and nerves are observed without parenchymal damage. The pancreatic lobules keep their contours, but the acinar cells are diminished and replaced by numerous inflammatory cells. These features provide clues to arrive at a diagnosis of type 1 AIP and to distinguish it from pancreatic carcinoma on imaging. In contrast, type 2 AIP is an epithelium-centered inflammation involving the ducts and lobules. Neutrophilic infiltration in the epithelium and/or lumens (granulocytic epithelial lesion) is a characteristic finding. Lobular swelling due to inflammation is the cause of pancreatic enlargement. IgG4-related sclerosing cholangitis is histologically similar to the hypertrophic ductal lesion in type 1 AIP and characterized by wall thickening due to inflammation and luminal stenosis. The epithelium is intact, which is different from bile duct carcinomas and primary sclerosing cholangitis, the latter of which is characterized by inflammation targeting the epithelium. Although the histological features of type 1 AIP and IgG4-related sclerosing cholangitis are unique, the biopsy diagnosis of these diseases has limitations, which should be recognized by clinicians.

Endoscopic ultrasound-guided tissue acquisition for the histopathological diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a disease concept that originated in Japan. It is characterized by diffuse pancreatic enlargement and irregular narrowing of the main pancreatic duct. Although the usefulness of the histological diagnosis of AIP using endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) and EUS-guided fine-needle biopsy (FNB) has been reported, enhanced diagnostic performance is expected with improvements in tissue collection methods and fine-needle techniques. Guidance for establishing the tissue diagnosis of AIP has been developed and is useful for histological evaluation. Histopathological diagnosis by EUS-FNA/FNB is expected to play a central role in AIP diagnosis in the future.

The Role of EUS-Guided FNA and FNB in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is an increasingly recognized disease classified into two different subtypes based on histology. According to the International Diagnostic Criteria (ICDC), the diagnosis is achieved using a combination of different criteria. In patients presenting with a typical imaging appearance, the diagnosis may be straightforward, and steroid treatment is recommended, even without histological confirmation. In patients with atypical imaging or mass-forming appearance, the differential diagnosis with pancreatic cancer is challenging and crucial for treatment strategy. Endoscopic ultrasound (EUS)-guided tissue acquisition has been proposed to achieve a histological diagnosis. Fine-needle aspiration (FNA) was first proposed to aspirate cells from pancreatic lesions. Despite excellent results in terms of sensitivity for pancreatic cancer, the data are disappointing regarding the diagnosis of AIP. The recent development of new needles allowing fine-needle biopsy (FNB) has been associated with improved diagnostic accuracy based on preserving the tissue architecture, which is necessary to detect the typical histological features of AIP. However, the published literature on the role of EUS-guided FNA and FNB is limited and mainly focused on type 1 AIP. The present study aimed to review the available literature on the role of EUS-guided FNA and FNB in the diagnosis of AIP.

Late-onset type-2 autoimmune pancreatitis with two mass lesions diagnosed by endoscopic ultrasound-guided fine-needle aspiration

A 65-year-old man with ulcerative colitis presented with aggravated diabetes. Computed tomography showed two masses in the body and tail of the pancreas. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed, with histopathological findings suggesting autoimmune pancreatitis (AIP). Type-2 AIP was suspected, and administration of prednisolone was initiated. The pancreatic masses had disappeared after the treatment. In this case, EUS-FNA was effective for the diagnosis of type-2 AIP. The two-lesion mass formation observed here is a rare presentation of the disease. In patients with a history of ulcerative colitis, the possibility of late-onset type-2 AIP should be kept in mind.

Prospective study of EUS-guided tissue acquisition with a 20G core biopsy needle with a forward bevel for solid pancreatic mass

There is a growing need for tissue collection for immunostaining and genetic testing. Recently, several fine-needle biopsy needles are commercially available for endoscopic ultrasound-guided tissue acquisition.This prospective historical controlled study evaluates a 20G core biopsy needle with a forward bevel for solid pancreatic masses larger than 15 mm in diameter. The primary endpoint was the accuracy of histological diagnosis. The secondary endpoints included technical success rate, sample adequacy for histology, cytological diagnostic accuracy, and adverse events.Seventy consecutive patients were enrolled between January and October 2017. We achieved technical success in all cases regardless of the puncture sites or the endosonographer's experience. The final diagnoses were neoplasms in 67 patients (95.7%; pancreatic cancer in 65 patients, neuroendocrine neoplasm in 1, and malignant lymphoma in 1) and benign lesions in 3 patients (4.3%; autoimmune pancreatitis in 2 patients and mass-forming pancreatitis in 1). The obtained specimens were adequate for histological evaluation in all cases and the histological accuracy was 91.4% (95% confidence interval, 82.3-96.8%, P < .05) with the sensitivity and specificity of 91.0% and 100%, respectively. The cytological diagnostic accuracy was 95.7% and all patients were accurately diagnosed by combining cytological and histological examinations. As for adverse events, an asymptomatic needle fracture occurred in 1 case (1.4%).This 20G core biopsy needle with a forward bevel showed a high accuracy of histological diagnosis for solid pancreatic masses.

Utility of a 21-gauge Menghini-type biopsy needle with the rolling method for an endoscopic ultrasound-guided histological diagnosis of autoimmune pancreatitis: a retrospective study

Background

The histological diagnosis of autoimmune pancreatitis (AIP) by an endoscopic ultrasound (EUS)-guided approach is still challenging.

Methods

We investigated the utility of the 21-gauge Menghini-type biopsy needle with the rolling method for the histological diagnosis of AIP, in comparison with conventional 22-gauge needles. Among total 28 patients, rate of definitive histological diagnosis, acquired sample area of tissue, rate of histopathological diagnosis of AIP, and adverse events were retrospectively analyzed.

Results

Definitive histological diagnoses were successfully accomplished in all 14 patients (100%) treated with a Menghini-type needle, and in 57% of cases (8/14) treated with conventional 22-gauge needles (P < 0.001). The median sample area of the tissue, except for blood contamination, was remarkably larger by the Menghini-type needle than by conventional-type needles (6.2 [IQR, 4.5–8.8] versus 0.7 [IQR, 0.2–2.0] mm², P < 0.001), and the area per punctures was approximately 4 times larger (1.4 [IQR: 0.9–2.9] versus 0.3 [IQR: 0.1–0.6] mm²/puncture, P < 0.001). Based on the International Consensus Diagnostic Criteria, lymphoplasmacytic infiltration, abundant IgG4-postive cells, storiform fibrosis, and obliterative phlebitis were found in 86%/29%, 64%/0%, 36%/0%, and 7%/0% patients who were treated with the Menghini-type needle and conventional-type needles, respectively. Consequently, histopathological diagnosis with type 1 AIP (lever 1 or 2) was achieved in 9 patients (64%) treated with the Menghini-type needle and in no patient treated with conventional-type needles (P < 0.001). Two patients who had mild post-procedural pancreatitis improved with conservative treatment, and no bleeding occurred in patients treated with the Menghini-type needle.

Conclusion

EUS-guided rolling method with the 21-gauge Menghini-type biopsy needle is useful for the histopathological diagnosis of AIP, due to its abundant acquisition of good-quality tissue from the pancreas.

Autoimmune pancreatitis: Current perspectives

Over the last two decades, our knowledge and understanding regarding the pathogenesis and biology of autoimmune pancreatitis (AIP) have improved tremendously. Type 1 AIP or IgG4-related pancreatitis (IgG4-RP) is now believed to be the prototype of the multisystemic IgG4-related disease. In view of clinical features like obstructive jaundice and mass-forming lesions in the pancreas in elderly men, type 1 AIP often mimics pancreatic cancer. IgG4-related sclerosing cholangitis concomitantly involving the extrahepatic and intrahepatic biliary tree is the most common extrapancreatic involvement seen in up to 80% of these patients, which needs to distinguish from cholangiocarcinoma. Histology is characterised by lymphoplasmacytic inflammation, abundant IgG4 positive plasma cell infiltration, storiform fibrosis and obliterative phlebitis. Apart from histology, high serum IgG4 levels, pancreatic parenchymal and duct imaging findings and other organ involvement aid in diagnosis especially in cases where definitive histology is not evident. Also, these parameters lay the foundation of various diagnostic criteria proposed over last few years. On the contrary, histology alone is the mainstay for establishing diagnosis of idiopathic duct-centric pancreatitis (IDCP) as it lacks any specific serological marker or imaging. Since both types of AIP respond dramatically to corticosteroid treatment, a biopsy is crucial to establish the preoperative diagnosis and to exclude malignancy so as to avoid unnecessary surgery. This review discusses the morphologic spectrum, treatment and prognosis of IgG4-RP and IDCP with an emphasis on approach to diagnosis with relevant histologic features, differential diagnoses and the challenges faced during biopsy interpretation.

Diagnostic yield of endoscopic ultrasound-guided tissue acquisition in autoimmune pancreatitis: a systematic review and meta-analysis

Background and study aims  There is limited evidence on the diagnostic performance of endoscopic ultrasound (EUS)-guided tissue acquisition in autoimmune pancreatitis (AIP). The aim of this meta-analysis was to provide a pooled estimate of the diagnostic performance of EUS-guided fine-needle aspiration (FNA) and fine-needle biopsy (FNB) in patients with AIP. Patients and methods  Computerized bibliographic search was performed through January 2020. Pooled effects were calculated using a random-effects model by means of DerSimonian and Laird test. Primary endpoint was diagnostic accuracy compared to clinical diagnostic criteria. Additional outcomes were definitive histopathology, pooled rates of adequate material for histological diagnosis, sample adequacy, mean number of needle passes. Diagnostic sensitivity and safety data were also analyzed. Results  Fifteen studies with 631 patients were included, of which four were prospective series and one randomized trial. Overall diagnostic accuracy of EUS tissue acquisition was 54.7 % (95 % confidence interval, 40.9 %-68.4 %), with a clear superiority of FNB over FNA (63 %, 52.7 % to 73.4 % versus 45.7 %, 26.5 %-65 %; p < 0.001). FNB provided level 1 of histological diagnosis in 44.2 % of cases (30.8 %-57.5 %) as compared to 21.9 % (10 %-33.7 %) with FNA ( P  < 0.001). The rate of definitive histopathology of EUS tissue sampling was 20.7 % (12.9 %-28.5 %) and it was significantly higher with FNB (24.3 %, 11.8 %-36.8 %) as compared to FNA (14.7 %, 5.4 %-23.9 %; P  < 0.001). Less than 1 % of subjects experienced post-procedural acute pancreatitis. Conclusion  The results of this meta-analysis demonstrate that the diagnostic performance of EUS-guided tissue acquisition is modest in patients with AIP, with an improved performance of FNB compared to FNA.

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

BACKGROUND

The 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.

METHODS

A 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.

RESULTS

The 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).

CONCLUSIONS

Current 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.

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.

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.

Steroid-responsive pancreatitides

Autoimmune pancreatitis has received considerable attention, especially due to the marked effect of corticosteroid therapy on its clinical course. Knowledge, especially regarding type 1 autoimmune pancreatitis, has significantly increased over the last decades, and despite significant differences in pathophysiology and outcomes, both type 1 and 2 autoimmune pancreatitis are still considered different types of the same disease. Some have proposed a different nomenclature reflecting these differences. Although the term steroid-responsive pancreatitides may be interpreted as synonymous to type 1 and 2 autoimmune pancreatitis, these are not the only pancreatic conditions that show a response to steroid therapy. Acute pancreatitis caused by vasculitis and connective tissue diseases and acute pancreatitis secondary to checkpoint inhibitors or programmed cell death receptor antibody-mediated blockage cancer therapy may also benefit from steroid treatment. This review presents current concepts on these disorders, aiming to increase awareness, analyze similarities and differences, and propose a new nomenclature that reflects their specific particularities, clustering them under the term “steroid-responsive pancreatitides”.

Efficacy and limitations of the histological diagnosis of type 1 autoimmune pancreatitis with endoscopic ultrasound-guided fine needle biopsy with large tissue amounts

OBJECTIVES

We examined the efficacy and limitations of acquiring large specimens by endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) for diagnosing type 1 autoimmune pancreatitis (AIP).

METHODS

Patients from 12 institutions with non-neoplastic diseases or pancreatic ductal adenocarcinoma (PDAC) with large EUS-FNB specimens were investigated. Slides stained with hematoxylin-eosin, elastic, IgG4, and IgG stains were evaluated. The IgG4- and IgG-positive cell numbers were counted in three foci. The diagnoses were based on the Japan Pancreas Society 2011 (JPS 2011) criteria and the International Consensus Diagnostic Criteria (ICDC).

RESULTS

We analyzed 85 non-neoplastic (definite type 1 AIP in 73/85 based on the ICDC) cases and 64 PDAC cases. IgG4-positive cells were numerous (>10 in 85.9%), and the IgG4/IgG ratios were high (>40% in 81.2%). Plasma cell crushing by an artifact caused unsuccessful immunostaining, notably in smaller samples. Tissue lengths were an important factor for the presence of storiform fibrosis and obliterative phlebitis, but storiform fibrosis was equivocal even in large tissues. A definite or possible histological diagnosis was achieved in 45.9% (39/85) and 41.2% (35/85), respectively, and contributed to the definite final diagnosis of type 1 AIP in 33.3% (ICDC) and 55.6% (JPS 2011) in cases with segmental/focal lesions. In the PDAC group, >10 IgG4-positive cells was rare (2/58), but elastic stains revealed fibrous venous occlusions in 10.3% (6/58).

CONCLUSIONS

EUS-FNB with large tissue amounts was useful for diagnosing type 1 AIP, notably by facilitating successful IgG4 immunostaining, but definite diagnosis may not be achieved even in cases with large specimens.

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

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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%.

CONCLUSIONS

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.

Prediction of pancreatic atrophy after steroid therapy using equilibrium-phase contrast computed tomography imaging in autoimmune pancreatitis

Background and Aims

Imaging tools for predicting pancreatic atrophy after steroid therapy in autoimmune pancreatitis (AIP) have not been established. As delayed equilibrium‐phase contrast enhancement in computed tomography (CE‐CT) may reflect interstitial fibrosis, we evaluated the ability of equilibrium‐phase CT imaging for predicting pancreatic atrophy.

Methods

Forty‐six steroid‐treated AIP patients who underwent contrast‐enhanced CT at our university hospital were included in this retrospective study. CT attenuation (Hounsfield units [HU]) values in noncontrast images (NC) and equilibrium‐phase images (EP) and the differences in HU values between NC and EP images (SUB) were measured. Pancreatic volume was measured in CE‐CT before (Vol_pre) and after (Vol_post) steroid therapy. The volume reduction rate was calculated. The relationships of CT values with pancreatic atrophy, Vol_post, volume reduction rate, and diabetes exacerbation were investigated.

Results

CT values in the EP and SUB images before steroid therapy were associated with pancreatic atrophy after steroid therapy (atrophy vs nonatrophy 114.5 ± 12.8 vs 99.5 ± 11.1, P = 0.0002; 70.9 ± 14.72 vs 57.2 ± 13.1, P = 0.003, respectively), but CT values in NC images were not (P = 0.42). CT values in EP and SUB images before steroid therapy were correlated with Vol_post (EP images r = −0.70, P = 0.002; SUB images r = −0.68, P = 0.03) and volume reduction rate after steroid therapy (EP images: r = −0.55, P < 0.0001; SUB images r = −0.45, P = 0.002). Diabetes exacerbation was associated with higher EP and SUB values (P = 0.009 and P = 0.04, respectively).

Conclusion

Equilibrium‐phase contrast CT imaging may facilitate prediction of pancreatic atrophy after steroid therapy in AIP.

Can the wet suction technique change the efficacy of endoscopic ultrasound-guided fine-needle aspiration for diagnosing autoimmune pancreatitis type 1? A prospective single-arm study

BACKGROUND

Other than surgery, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the only procedure for histologically diagnosing autoimmune pancreatitis (AIP). However, adequate specimens are difficult to obtain. Recently, more adequate specimens were reported to be obtained with EUS-FNA with a wet suction technique (WEST) than with conventional EUS-FNA.

AIM

To histologically diagnose AIP by EUS-FNA with a WEST.

METHODS

Eleven patients with possible type 1 AIP between February 2016 and August 2018 underwent EUS-FNA with a WEST (WEST group), with four punctures by 19 or 22 G needles. As a historical control, 23 type 1 AIP patients who underwent no fewer than four punctures with 19 or 22 G needles were enrolled (DRY group). Patient characteristics and histological findings were compared between the two groups.

RESULTS

Three histopathological factors according to the International Consensus Diagnostic Criteria were significantly greater in the WEST group than the DRY group [lymphoplasmacytic infiltrate without granulocytic infiltration: 9 (81.8%) vs 6 (26.1%), P = 0.003, storiform fibrosis: 5 (45.5%) vs 1 (4.3%), P = 0.008, abundant (> 10 cells/HPF) IgG4-positive cells: 7 (63.6%) vs 5 (21.7%), P = 0.026]. Level 1 or level 2 histopathological findings were observed more often in the WEST group than in the DRY group [8 (72.7%) vs 3 (13.0%), P = 0.001].

CONCLUSION

EUS-FNA with a WEST was more successful than standard EUS-FNA in histologically diagnosing AIP.

Clinical features of isolated proximal-type immunoglobulin G4-related sclerosing cholangitis

BACKGROUND AND AIM

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) presents as isolated proximal-type sclerosing cholangitis (i-SC). The present study sought to clarify the imaging differences between i-SC and Klatskin tumor. Differences between i-SC and IgG4-SC associated with autoimmune pancreatitis (AIP-SC) were also studied.

METHODS

Differentiating factors between i-SC and Klatskin tumor were studied. Serum IgG4 level, CA19-9 level, computed tomography (CT) findings, cholangiography findings (symmetrical smooth long stricture extending into the upper bile duct [SSLS]), endosonographic features (continuous symmetrical mucosal lesion to the hilar part [CSML]), endoscopic biopsy results, treatment, relapse, and survival were also compared between patients with i-SC and those with AIP-SC.

RESULTS

For a differential diagnosis between i-SC (N = 9) and Klatskin tumor (N = 47), the cut-off value of serum IgG4 level was 150 mg/dL (sensitivity, 0.857, specificity, 0.966). Logistic regression analysis indicated that serum IgG4 level, presence of SSLS, presence of CSML, and presence of swollen ampulla are independent factor for identifying i-SC. Relapse rate was significantly higher in the IgG4-SC with AIP group than in the i-SC group (log rank, P = 0.046).

CONCLUSION

Isolated proximal-type sclerosing cholangitis presents as a nodular lesion with SSLS and/or CSML mimicking a Klatskin tumor. Those endoscopic features might provide a diagnostic clue for i-SC. i-SC is likely to have a more favorable prognosis than IgG4-SC with AIP.

Present state of endoscopic ultrasonography-guided fine needle aspiration for the diagnosis of autoimmune pancreatitis type 1

Autoimmune pancreatitis (AIP) is defined as pancreatitis caused by irregular narrowing of the pancreatic duct accompanied by pancreatic swelling, fibrosis and lymphocyte infiltration, events that are related to autoimmune mechanisms. The 2010 International Consensus Diagnostic Criteria for AIP defined pancreatitis as “type 1” when increased levels of serum IgG4 were present and other organs were involved; lymphoplasmacytic sclerosing pancreatitis was the main histological characteristic. Apart from surgery, endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is the only method for the histological diagnosis of AIP; however, this method is difficult. The use of larger-diameter FNA needles and trucut biopsy did not improve the diagnostic performance of EUS-FNA, but it has improved gradually. In this review, we look back at past efforts to improve the diagnostic performance of EUS-FNA and reveal the present state of EUS-FNA for the histological diagnosis of AIP type 1.

A Diagnostically Challenging Case of Autoimmune Pancreatitis Due to Contamination of the Pathological Specimen with Early Gastric Cancer

A 73-year-old man with worsened diabetes underwent abdominal computed tomography and was diagnosed with localized enlargement of the pancreatic tail. Based on the suspicion of autoimmune pancreatitis, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed. A cytologic examination showed findings suggestive of adenocarcinoma. Due to discrepancies between the imaging and pathological findings, esophagogastroduodenoscopy was performed. An extensive early gastric cancer lesion was detected in the posterior wall of the gastric corpus. It was therefore likely that puncturing through the tumor resulted in the contamination with cancer tissue. The possibility of a concomitant malignancy should be considered in EUS-FNA, and thorough examinations should be conducted.

The role of EUS-guided fine needle aspiration in autoimmune pancreatitis: a single center prospective study

OBJECTIVES

Histopathological examination is pivotal in diagnosing autoimmune pancreatitis (AIP). The usefulness of EUS-guided fine needle aspiration (EUS-FNA) in diagnosing AIP remains controversial worldwide. The authors conducted this study to evaluate the efficacy of EUS-FNA for AIP diagnosis using a 22-gauge needle.

METHODS

Between January 2013 and May 2017, 37 patients had imaging studies suggestive of AIP at Tongji Hospital, and 27 patients of them were enrolled in this study. Tissue specimens acquired through EUS-FNA were analyzed for periductal lymphoplasmacytic infiltrate (LPI), storiform fibrosis (SF), obliterative phlebitis (OP) and immunoglobulin G4 (IgG4)-positive plasma cell counts. Clinical Trials.gov no: TJ-C20121220.

RESULTS

LPI and SF were present in 18 (66.67%) and 18 (66.67%) of 27 patients, respectively. Abundant IgG4-positive plasmacyte infiltration >10/high-power field (HPF) was detected in 8 of 27 patients (29.63%). OP and the characteristic findings of idiopathic duct-centric chronic pancreatitis (IDCP) and granulocytic epithelial lesion (GEL) were not detected in this study. According to the International Consensus Diagnostic Criteria (ICDC) for AIP, 5 and 12 of 27 patients were assessed as having level 1 and level 2 histological findings, respectively, suggesting that 17 of 27 patients (62.96%) had lymphoplasmacytic sclerosing pancreatitis (LPSP) based on the ICDC.

CONCLUSIONS

In 92.6% of patients, pancreatic tissues with >5 HPFs were obtained by EUS-FNA using a 22-G needle. In 63% of patients, histology was evaluated to be ≥ level 2 according to the ICDC. The study indicates that EUS-FNA with a 22-G needle is valuable in the histopathological diagnosis of AIP.

Type 2 Autoimmune Pancreatitis with Crohn's Disease

Autoimmune pancreatitis (AIP) is a distinct subtype of pancreatitis, which is classified into type 1 and 2 based on the clinicopathological features. According to the international consensus diagnostic criteria, pancreas resection or core biopsy specimens are recommended to make an accurate histological evaluation. However, the usefulness of endoscopic ultrasonography (EUS) guided fine needle aspiration (FNA) for histological evaluation has also been reported. Furthermore, the simultaneous presentation of type 2 AIP and Crohn's disease (CD) is very rare, especially in the Asian population. Therefore, we herein report a case of type 2 AIP with CD, which was diagnosed using EUS guided FNA with a 22-gauge needle.

Management of Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP) is an IgG-4-related systemic disease that can manifest as a pancreatic disorder or another disorder of presumed autoimmune origin. Type 2 disease is typically characterized by absent IgG-4-positive cells. As patients often present with acute pancreatitis, obstructive jaundice, or pancreatic mass, it is imperative to exclude malignancy, a more common diagnosis. AIP may respond to corticosteroids, and has a strong association with other immune-mediated diseases. Recent literature suggests the benefit of immune-modulating therapy, including rituximab, although no consensus exists. This review covers the essentials of diagnosis, but focuses primarily on management of AIP.

Endoscopic ultrasound-guided fine-needle aspiration biopsy for diagnosis of gastric linitis plastica with negative malignant endoscopy biopsies

The value of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy in the gastric linitis plastica (GLP) with negative malignant endoscopy biopsies was investigated. Forty-six patients with linitis plastica who had undergone EUS-FNA were retrospectively studied, and their clinicopathological data were examined. Among the 46 eligible patients, 38 cases were diagnosed clearly by EUS-FNA. There were 24 cases with lymph node metastasis in the 38 patients. Both the lymph nodes and gastric lesions were punctured by EUS-FNA in the 24 cases. We compared the diagnostic accuracy in different sites, and the results showed that the diagnostic accuracy in lymph nodes was significantly higher than that in gastric lesions (P<0.05). Among them, 16 patients underwent surgical resection, and the accuracy of the pathological diagnosis by EUS-FNA was 87.5% (14/16). The preoperative diagnostic accuracy of T and N staging by endoscopic ultrasound (EUS) were both 75%. Neither severe hemorrhage nor perforation occurred in any patient. In conclusion, EUS-FNA is a safe and effective procedure for the diagnosis of indefinite linitis plastica, and puncturing metastatic lymph nodes can improve the diagnostic accuracy.

Pathological and Molecular Aspects to Improve Endoscopic Ultrasonography-Guided Fine-Needle Aspiration From Solid Pancreatic Lesions

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been applied to pancreatic lesions since the 1990s, and its use is now widespread. Improvements in endoscopic devices and sampling techniques have resulted in excellent diagnostic ability for solid pancreatic lesions. However, clinical improvements alone are not responsible for it; pathological aspects have also played important roles. Rapid on-site evaluation minimizes endoscopic procedures, although its value at improving the diagnostic ratio is still debated. Diagnostic efficacy differs by sample preparations (direct smear, cytospin, liquid-based cytology, cell block, and biopsy) and by staining methods (Papanicoloau, Diff-Quik, hematoxylin-eosin, and Giemsa). Several immunocytochemistry protocols aid in diagnosing epithelial components with cytological atypia and in differentiating various tumor types. One cytopathology diagnostic system is telecytology, which uses transmitted digital images and enables real-time diagnosis of EUS-FNA samples by expert cytologists at remote locations. However, EUS-FNA samples are useful for more than just diagnoses, as molecular analysis of these samples allows the identification of prognostic markers, such as genetic alterations in K-ras and EGFR. Expression of drug-metabolizing enzymes, human equilibrative nucleoside transporter 1, correlates with the response to gemcitabine-based chemotherapy. These pathology efforts have enhanced the diagnostic efficacy of EUS-FNA, thereby leading to better outcomes for patients with pancreatic diseases.

Clinical and pathophysiological aspects of type 1 autoimmune pancreatitis

In 1995, Yoshida and colleagues proposed the concept of "autoimmune pancreatitis" (AIP), which has recently been recognized as a new pancreatic inflammatory disease. Recent studies have suggested the existence of two subtypes of AIP: type 1, which involves immunoglobulin G4 (IgG4) and is the pancreatic manifestation of IgG4-related disease (IgG4-RD); and type 2, which is characterized by granulocytic epithelial lesions. Type 2 AIP is thought to be rare in Japan. Type 1 AIP is characterized by increased serum IgG4 concentrations, lymphoplasmacytic infiltrations, storiform fibrosis, and obliterative phlebitis. However, although type 1 AIP has become increasingly recognized, many clinical and basic issues remain to be solved. This review provides an overview of the recent clinical and basic knowledge of type 1 AIP.

Endoscopic Ultrasonography-Guided Fine Needle Aspiration Can Be Used to Rule Out Malignancy in Autoimmune Pancreatitis Patients

OBJECTIVES

The aim of this study was to review the suitability of endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) for ruling out malignancy in autoimmune pancreatitis patients.

METHODS

We retrospectively reviewed 40 autoimmune pancreatitis patients (type 1:37 patients; type 2: two patients; possible autoimmune pancreatitis: one patient) who received EUS-FNA. Among the 40 autoimmune pancreatitis patients, 34 were not histopathologically diagnosed with autoimmune pancreatitis by EUS-FNA, and they were followed up for more than 6 months in our hospital. Moreover, 14 pancreatic cancer patients who were not diagnosed by EUS-FNA were selected as a control group. These 14 patients constituted 3.9% of the 360 pancreatic cancer patients who received EUS-FNA. We evaluated the prognoses of the 34 autoimmune pancreatitis patients and the clinical differences between these 34 autoimmune pancreatitis patients and the 14 pancreatic cancer patients.

RESULTS

All 34 autoimmune pancreatitis patients showed reduced pancreatic swelling. The main pancreatic duct dilation ( > 3 mm), the diameter of the main pancreatic duct, the capsule-like rim sign, and serum CA19-9 levels were significantly different between the autoimmune pancreatitis and pancreatic cancer patients (2.9% versus 69.2%, P < .01; 1.7 ± 1.6 mm versus 6.8 ± 5.0 mm, P < .01; 79.4% versus 0%, P < .01; 41.4 ± 79.0 U/mL versus 2079.1 ± 275.3 U/mL, P = .02).

CONCLUSIONS

Almost all pancreatic cancers can be diagnosed by EUS-FNA. Furthermore, other clinical characteristics of pancreatic cancer undiagnosed by EUS-FNA were different from autoimmune pancreatitis undiagnosed by EUS-FNA. Endoscopic ultrasonography-guided FNA can be used to rule out malignancy in autoimmune pancreatitis patients.

The Role of Endoscopic Ultrasound in the Diagnosis of Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is increasingly being recognized due to improved understanding of the disease and its criteria for diagnosis. The classic type 1 AIP can be diagnosed on clinical data, but type 2 AIP requires histologic confirmation. Current criteria incorporate cross-sectional imaging and endoscopic retrograde cholangiopancreatography in the diagnosis of AIP. However, endoscopic ultrasound (EUS) will likely have an increasing role in the diagnosis through its characteristic imaging, image-enhancing techniques, and its ability to acquire tissue through either fine needle aspiration or biopsy. This article will review the diagnostic challenges of AIP and the current role of EUS.

Type 2 Autoimmune Pancreatitis: A Challenge in the Differential Diagnosis of a Pancreatic Mass

Introduction

Autoimmune pancreatitis is a rare entity of unknown etiology that can mimic pancreatic cancer and whose diagnosis involves clinical, serological, imagiological, and histological findings. There are two types of autoimmune pancreatitis: type 1, in which the pancreas is involved as one part of a systemic immunoglobulin G4-related disease, and type 2, generally without immunoglobulin G4-positive cells and without systemic involvement.

Case

We report the case of a 45-year-old female, who underwent an abdominal magnetic resonance imaging for etiological study of a solid liver lesion, which revealed a tail pancreatic mass. 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 and the patient underwent a laparoscopic distal pancreatectomy. Histopathology examination confirmed the diagnosis of type 2 autoimmune pancreatitis.

Conclusion

This case highlights the challenge in the diagnostic approach of a pancreatic mass, particularly in distinguishing benign from malignant disease.

From Pathogenesis, Clinical Manifestation, and Diagnosis to Treatment: An Overview on Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis which is autoimmune mediated. The international consensus diagnostic criteria (ICDC) 2011 proposed two types of AIP: type I is associated with histological pattern of lymphoplasmacytic sclerosing pancreatitis (LPSP), characterized by serum IgG4 elevation, whereas type 2 is named idiopathic duct-centric pancreatitis (IDCP), with granulocytic epithelial lesion (GEL) and immunoglobulin G4 (IgG4) negative. The pathogenic mechanism is unclear now; based on genetic factors, disease specific or related antigens, innate and adaptive immunity may be involved. The most common clinical manifestations of AIP are obstructive jaundice and upper abdominal pain. The diagnosis can be made by a combination of parenchymal and ductal imaging, serum IgG4 concentrations, pancreatic histology, extrapancreatic disease, and glucocorticoid responsiveness according to ICDC 2011. Because of the clinical and imaging similarities with pancreatic cancer, general work-up should be done carefully to exclude pancreatic malignant tumor before empirical trial of glucocorticoid treatment. Glucocorticoid is the most common drug for AIP to induce remission, while there still exists controversy on steroid maintenance and treatment for relapse. Further studies should be done to identify more specific serum biomarkers for AIP, the pathogenic mechanisms, and the treatment for relapse.