The advent of the first electric driven EUS-guided 17 gauge core needle biopsy - A pilot study on subepithelial lesions.

BACKGROUND AND AIMS: This pilot study aimed to evaluate safety and tissue sampling from subepithelial lesions (SEL) in the upper gastrointestinal tract with a novel electric motor driven endoscopic ultrasonography (EUS)-guided 17-gauge (G) size core needle biopsy (CNB) instrument. METHODS: An investigator-led prospective open label, performance and safety control study, including seven patients (female n = 4, median 71 y, range 28-75) with a determined SEL (median size 30 mm, range 17-150 mm) in the upper digestive tract (stomach n = 6, duodenum n = 1) were eligible and later followed up 14 days after index procedure. All investigations were completed according to protocol with three FNB 22-G passes with four fanning strokes and two EndoDrill® 17-G passes with three fanning strokes. RESULTS: Quality of samples as 'visible pieces' (>5 mm): FNB (n = 5/7) (fragmented/blood imbibed n = 1, poor tissue quantity n = 1) compared with 17-G CNB (n = 7/7). Histological result which led to final diagnosis (leiomyoma n = 2, adenocarcinoma n = 1, schwannoma n = 1, neuroendocrine tumour n = 1, desmoid tumour n = 1 and gastrointestinal stromal tumour (GIST) n = 1) could be obtained with the 17-G CNB instrument in all seven patients. FNB technique reached correct diagnosis in six patients. No serious adverse event were recorded. CONCLUSIONS: By using an electric driven 17-G biopsy device, a true cylinder of core tissue can be obtained in one single puncture from the area of interest reducing the need for a second sampling. The absolute benefit of EUS-guided CNB is that the sample can be handled and histologically prepared in the same manner as standard percutaneous core needle sample, e.g., breast and prostate cancer.

Application of endoscopic ultrasound-guided hepaticogastrostomy combined with antegrade stenting in patients with malignant biliary obstruction after failed ERCP.

BACKGROUND: This study was aimed at comparing the safety and effectiveness of endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) and EUS-HGS combined with antegrade stenting (EUS-HGAS) in patients with malignant biliary obstruction (MBO) after failed endoscopic retrograde cholangiopancreatography (ERCP). METHODS: Patients diagnosed with MBO and receiving EUS-HGS or EUS-HGAS from September 2015 to October 2020 were enrolled in this study. Clinical success, complications, reintervention rate, post-operative hospital stay, time to stent dysfunction, and patient death were compared. RESULTS: A total of 45 patients (21 in the EUS-HGAS group and 24 in the EUS-HGS group) were enrolled in this study. In the EUS-HGAS group, 21 patients all achieved clinical success (100%); in the EUS-HGS group, 24 patients also achieved technical success (100%) (P > 0.05). The differences between pre- and post-operative TB and ALT and AST levels were greater in the single-step EUS-HGAS group (P < 0.05). The incidence of complications was 2 of 21 (9.5%) in the EUS-HGAS group and 5 of 24 (20.8%) in the EUS-HGS group (P > 0.05). The reintervention rate was 0 in the EUS-HGAS group and 1 (4.2%) in the EUS-HGS group (P > 0.05). Time to stent dysfunction or patient death was longer in the EUS-HGAS group (P < 0.05). The post-operative hospital stay was longer and the total cost was higher in the EUS-HGAS group. CONCLUSION: EUS-HGAS was superior to EUS-HGS in terms of biliary drainage effectiveness and time to stent dysfunction or patient death in patients with MBO after failed ERCP. Furthermore, two-step EUS-HGAS may be safer in some patients.

EUS in the diagnosis of pathologically undiagnosed esophageal tuberculosis.

BACKGROUND: Esophageal tuberculosis (ET) is relatively rare, and the diagnosis is challenging. The aim of this study was to evaluate the clinical features of ET and highlight the role of endoscopic ultrasonography (EUS) in the diagnosis of pathologically undiagnosed ET. METHODS: We retrospectively analysed the clinical features, radiological performances, conventional endoscopic appearances, EUS features, treatment and outcomes of pathologically undiagnosed ET between January 2011 and December 2018. All 9 patients failed to be diagnosed by at least two repeated biopsies (such as routine biopsy, multipoint or deep biopsy, and even or EUS-guided fine-needle aspiration (EUS-FNA)). RESULTS: Nine patients (66.7% female) with a mean age of 45 years (range 29-59) complained of retrosternal pain or discomfort, or (and) dysphagia. Esophagoscopy demonstrated protruding lesions in the mucosa with central ulcers or erosion in five patients, submucosal bulges with smooth surfaces in one patient, submucosal bulges with diverticula in one patient, ulcers with suspicious fistula formation in one patient, and multiple ulcers in one patient. None of the patients received confirmed histopathological or bacteriological diagnoses by repeated biopsies. However, they were first suspected to have ET based on EUS examination. Because EUS found some characteristic ultrasonographic changes, which were very helpful for the diagnosis of ET when combined with clinical manifestations, the patients subsequently received diagnostic antituberculosis therapy. Finally, the patients recovered or improved with follow-up times ranging from 3 to 10 months. CONCLUSIONS: EUS could help in the diagnosis of ET on basis of EUS features like poorly defined esophageal wall structure, enlarged paraesophageal or mediastinal lymph nodes, hypoechoic lesions of esophageal wall that are linked to the enlarged paraesophageal lymph nodes. However all attempts should be made to obtain histological or microbiological diagnosis.

Multicenter prospective evaluation study of endoscopic ultrasound-guided hepaticogastrostomy combined with antegrade stenting (with video).

BACKGROUND AND AIM: Endoscopic ultrasonography-guided hepaticogastrostomy (EUS-HGS) is often indicated for advanced stage patients. Therefore it is important to prevent adverse events associated with EUS-HGS procedures and obtain long stent patency. EUS-guided antegrade stenting (AS) has been developed as an advanced technique. Thus, to prevent adverse events and achieve long stent patency, EUS-AS combined with EUS-HGS (EUS-HGAS) has been reported. The aim of the present study was to evaluate the technical feasibility and efficacy of EUS-HGAS in a multicenter, prospective study. METHODS: This prospective study was carried out at each hospital of the Therapeutic Endoscopic Ultrasound Group. Primary endpoint of this multicenter prospective study was stent patency of EUS-HGAS. RESULTS: A total of 49 patients were enrolled. Technical success rate of EUS-HGS was 95.9% (47/49). EUS-AS failed in five patients because the guidewire could not be advanced into the intestine across the bile duct obstruction site. Therefore, EUS-HGAS was successfully carried out in 40 patients (technical success rate: 85.7%). Median overall survival was 114 days. Median stent patency including stent dysfunction and patient death was 114 days. In contrast, mean stent patency was 320 days. Adverse events were seen in 10.2% (5/49) of cases. Hyperamylasemia was seen in four patients, and bleeding was seen in one patient. CONCLUSIONS: The present study is the first to evaluate EUS-HGAS. EUS-HGAS has clinical benefit for obtaining long stent patency and avoiding adverse events, although the possibility of acute pancreatitis as a result of obstruction of the orifice of the pancreatic duct must be considered.

State of endoscopic ultrasonography in Spain in 2017. / Estado de la ecoendoscopia en España en 2017.

AIM: To understand the current state of endoscopic ultrasonography (EUS) in Spain. METHODS: Descriptive analysis from a national survey with 11 questions: 10 related to technique and 1 to the training and experience of the endoscopists. RESULTS: Sixty endoscopists from 48 of the 97 (49.5%) hospitals that perform EUS in Spain responded to the survey. A total of 28,678 procedures (20,311 diagnostic, 7,446 with puncture and 921 therapeutic) were recorded over the course of one year. Approximately 64% of the hospitals perform between 300 and 999 tests per year. All have radial and sectorial echoendoscopes, with a median of 2 (2-8) scopes. For cytological diagnosis, the 22-gauge needle is the most commonly used (98%) and, for histological diagnosis, the Procore (72%). The study of the pancreas and bile duct is the most common indication for diagnostic EUS (60%), followed by the staging of digestive tract neoplasms (20%). Approximately 72% of the hospitals perform on-site cytopathology evaluations and sedation is administered in equal parts by both endoscopists and anaesthetists. In terms of experience, 45% of echoendoscopists perform fewer than 300 annual exams and the median training duration is 6months (0.5-36). CONCLUSIONS: EUS is adequately implemented in Spain and good equipment is available. However, it is necessary to establish a standardised EUS training program since the one undertaken by many echoendoscopists could prove insufficient according to the standards established by Scientific Societies.

Interventional endoscopic ultrasonography: Where are we headed?

Endoscopic ultrasonography (EUS) is an essential endoscopic tool within the diagnostic and therapeutic armamentarium of gastrointestinal and hepatic diseases. EUS-guided tissue acquisition will develop towards facilitating personalized treatment by obtaining large representative tissue specimens for elaborate immunohistochemical and biomolecular typing of the tumor. Intratumoral or intravascular delivery of drugs potentially offers many advantages over systemic injection. Intratumoral application of radiofrequency ablation and photodynamic therapy show promise but need to be explored further. Appositioning and connecting luminal structures within the gastrointestinal tract using fully covered expandable lumen-apposing stents will expand its indication far beyond the drainage of (infected) fluid collections and EUS-guided gastrojejunostomy is a particularly exciting development that could have significant impact on the management of gastric outlet obstruction.

Endoscopic ultrasonography-guided choledochoduodenostomy using a newly designed laser-cut metal stent: Feasibility study in a porcine model.

BACKGROUND AND AIM: Endoscopic ultrasonography (EUS)-guided choledochoduodenostomy (EUS-CDS) is increasingly used in the treatment of malignant distal biliary obstruction. Standardized use of this technique requires improvements in instruments, including more convenient and safer devices. The present study was designed to evaluate the resistance force to migration (RFM) of a newly designed laser-cut metal stent and the feasibility of EUS-CDS using this stent. METHODS: This experimental study used a porcine model of biliary dilatation involving five male pigs. The new stent is a fully covered laser-cut stent with anti-migration anchoring hooks. The RFM of the new stents was compared with those of three commercially available covered metal stents using a phantom model. In the animal study, after ligation of Vater's ampulla with endoscopic clips, the dilated common bile duct was punctured under EUS guidance, followed by EUS-CDS using the new stent. One week after the procedure, the stents were removed endoscopically and the fistulas were assessed after the pigs were killed. Technical feasibility and clinical outcomes were evaluated. RESULTS: Among the four stents, the new stent had the highest RFM. Metal stent placement was successful in all five pigs, with no procedure-related complications occurring during and 1 week after endoscopic intervention. All stents remained in place without migration and were removed easily using a snare. At necropsy, fistulas were created between the bile duct and duodenum in all pigs. CONCLUSION: EUS-CDS using a newly designed metal stent was feasible and effective in this porcine model of biliary dilatation.

Indications for endoscopic ultrasonography (EUS)-guided biliary intervention: Does EUS always come after failed endoscopic retrograde cholangiopancreatography?

BACKGROUND AND AIM: Endoscopic ultrasonography-guided biliary drainage (EUS-BD), first reported as an alternative to percutaneous transhepatic biliary drainage (PTBD) after failed endoscopic retrograde cholangiopancreatography (ERCP), is increasingly reported as a primary procedure without failed ERCP. The present study aims to evaluate the outcomes of therapeutic biliary ERCP and to compare the safety and effectiveness of primary EUS-BD with those of ERCP, rescue EUS-BD and PTBD. METHODS: We retrospectively studied therapeutic biliary ERCP as well as subsequent rescue PTBD and EUS-BD. Additionally, indications, safety and technical success of primary EUS-BD were evaluated. RESULTS: Between August 2013 and September 2015, a total of 520 therapeutic biliary ERCP with a native papilla were analyzed. We encountered 23 cases with inaccessible papilla and 22 cases with failed cannulation, which were rescued by 21 PTBD, 16 EUS-BD and two repeat ERCP. Additionally, 40 primary EUS-BD were carried out during the same period as a result of 10 recurrent cholangitis cases after transpapillary drainage, five outside failed cannulation, four altered anatomy, two history of ERCP-related adverse events (AE), two technical difficulties in stenting under enteroscopy-assisted ERCP and 17 on study protocol. Technical success and AE rates were 95.6% and 14.5% in ERCP, 90.5% and 33.3% in rescue PTBD, 93.8% and 18.8% in rescue EUS-BD, and 95.0% and 22.5% in primary EUS-BD, respectively. CONCLUSIONS: Rescue EUS-BD was used in 3.1% among all ERCP. Given the comparable technical success and AE rates of both primary and rescue EUS-BD, primary EUS-BD without failed ERCP can be a treatment option if it provides advantages over ERCP.

Endoscopic ultrasonography-guided transmural drainage of walled-off pancreatic necrosis: Comparison between a specially designed fully covered bi-flanged metal stent and multiple plastic stents.

BACKGROUND AND AIM: Endoscopic ultrasonography (EUS)-guided drainage of walled-off necrosis (WON) may be carried out by placement of multiple plastic stents (MPS) or specially designed fully covered bi-flanged metal stents (BFMS). Comparative data on efficacy of these two stent types for WON drainage are limited. This retrospective study compares outcomes of WON drainage using BFMS and MPS. METHODS: During a 10-year period, 133 patients underwent EUS-guided WON drainage. MPS or BFMS were placed in a WON cavity through a single puncture, and direct endoscopic necrosectomy (DEN) was carried out whenever clinically necessary. Data in the two cohorts were retrospectively compared for primary outcomes - clinical success, adverse events and mortality; and secondary outcomes - DEN requirement, mean DEN sessions, need for salvage surgery and hospital stay. RESULTS: MPS were placed in 61 and BFMS in 72 patients. Patients undergoing BFMS drainage required fewer DEN sessions (mean 1.46 vs 2.74, P < 0.05), had fewer adverse events (5.6% vs 36.1%, P < 0.05), needed salvage surgery less often (2.7% vs 26.2%, P < 0.05), and had significantly shorter hospital stay (4.1 vs 8 days, P < 0.05) compared to those undergoing MPS drainage. There was no difference in DEN requirement (P = 0.217) and mortality (P = 0.5) in both groups. Overall clinical success with BFMS was superior to MPS (94% vs 73.7%, P < 0.05). CONCLUSION: BFMS appear to be superior to MPS for EUS-guided WON drainage in terms of clinical success, number of DEN sessions, adverse events, need for salvage surgery and hospital stay.

Diagnostic and treatment strategy for small gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are considered to be potentially malignant mesenchymal tumors of the gastrointestinal tract. Clinically relevant GISTs are rare; however, subclinical GISTs (mini-GISTs) (1-2 cm) and pathologic GISTs (micro-GISTs) (<1 cm) are frequently reported. Most mini-GISTs and almost all micro-GISTs of the stomach may exhibit benign clinical behavior, and only mini-GISTs with high-risk features may progress. For this review, a provisional algorithm was used to propose diagnostic and treatment strategies for patients with small GISTs. Because surgery is the only potentially curative treatment, in its application for small GISTs, the principles of sarcoma surgery should be maintained, and cost effectiveness should be considered. Indications for surgery include GISTs measuring ≥2 cm, symptomatic GISTs, and mini-GISTs with high-risk features (irregular borders, cystic spaces, ulceration, echogenic foci, internal heterogeneity, and tumor progression during follow-up); however, a preoperative pathologic diagnosis is infrequently obtained. For small intestinal and colorectal GISTs, surgery is indicated irrespective of size because of their greater malignant potential. Otherwise, mini-GISTs without high-risk features, micro-GISTs, and small submucosal tumors measuring <5 cm without high-risk features may be followed by periodical endoscopic ultrasonography. Although surgical approaches and operative methods are selected according to tumor size, location, growth pattern, and surgical teams, laparoscopic surgery has produced similar oncologic outcomes and is less invasiveness compared with open surgery. After resection, pathologic examination for diagnosis and risk assessment is mandatory, and genotyping is also recommended for high-risk GISTs. Endoscopic resection techniques, although feasible, are not routinely indicated for most mini-GISTs or micro-GISTs. Cancer 2016;122:3110-8. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Efficacy of endoscopic ultrasonography and endoscopic ultrasonography-guided fine-needle aspiration for the diagnosis and grading of pancreatic neuroendocrine tumors.

BACKGROUND AND AIM: Pancreatic neuroendocrine tumors (pNETs) are histologically categorized according to the WHO 2010 classification by their mitotic index or Ki-67 index as G1, G2, or G3. The present study examined the efficacy of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis and grading of pNET. METHODS: We retrospectively reviewed 61 pNETs in 51 patients who underwent EUS between January 2007 and June 2014. All lesions were pathologically diagnosed by surgical resection or EUS-FNA. We evaluated the detection rates of EUS for pNET and sensitivity of EUS-FNA, and compared the Ki-67 index between EUS-FNA samples and surgical specimens. EUS findings were compared between G1 and G2/G3 tumors. RESULTS: EUS showed significantly higher sensitivity (96.7%) for identifying pNET than CT (85.2%), MRI (70.2%), and ultrasonography (75.5%). The sensitivity of EUS-FNA for the diagnosis of pNET was 89.2%. The concordance rate of WHO classification between EUS-FNA and surgical specimens was 69.2% (9/13). The concordance rate was relatively high (87.5%, 5/6) in tumors <20 mm but lower (57.1%; 4/7) in tumors ≥20 mm. Regarding EUS findings, G2/G3 tumors were more likely to be large (>20 mm), heterogeneous, and have main pancreatic duct (MPD) obstruction than G1 tumors. Multivariate analysis showed large diameter and MPD obstruction were significantly associated with G2/G3 tumors. CONCLUSIONS: EUS and EUS-FNA are highly sensitive and accurate diagnostic methods for pNET. Characteristic EUS findings such as large tumor size and MPD obstruction are suggestive of G2/G3 tumors and would be helpful for grading pNETs.

Current situation of endoscopic biliary cannulation and salvage techniques for difficult cases: Current strategies in Japan.

In the pancreatobiliary session at Endoscopic Forum Japan (EFJ) 2015, current trends of routine biliary cannulation techniques and salvage techniques for difficult biliary cannulation cases were discussed. Endoscopists from nine Japanese high-volume centers along with two overseas centers participated in the questionnaires and discussion. It was concluded that, currently, in Western countries, the wire-guided cannulation (WGC) technique is favored during initial cannulation attempts. However, the conventional technique using an endoscopic retrograde cholangiopancreatography catheter with contrast medium injection is still used as first choice at most Japanese high-volume centers. The WGC technique is used as the second choice at some institutions only. After failed biliary cannulation attempts, the initial salvage option preferred in most centers includes pancreatic guidewire placement, followed by precut techniques as the second salvage choice. Among several precut techniques, the free-hand needle knife sphincterotomy with cutting upwards from the pancreatic duct is most popular. Endoscopic ultrasonography-guided rendezvous technique is also carried out as a final salvage option at select institutions.

Multicenter evaluation of the utilization of endoscopic ultrasound.

BACKGROUND AND AIM: There are currently no data regarding the number and type of endoscopic ultrasound (EUS) procedures being carried out in the USA. The aims of the present study are to: (i) estimate the annual number of EUS procedures being carried out in a nationwide database; (ii) describe the indications and types of EUS carried out; and (iii) examine short-term trends in volume. METHODS: Retrospective analysis from the Clinical Outcomes Research Initiative (CORI) of EUS procedures carried out on patients >18 years of age from 1 January 2010 through 31 December 2013. RESULTS: EUS cases (n = 7614) were carried out by 68 endoscopists at 18 sites over the study period, representing 1.7% of the total number of endoscopic procedures. The most common indications were evaluation of a pancreatic mass (14.7%), diagnostic sampling with fine-needle aspiration (14.1%), and evaluation of a pancreatic cyst (14.0%). The number of EUS examinations and cases undergoing same-day endoscopic retrograde cholangiopancreatography (ERCP) increased over the study period (P < 0.0001). Use of general anesthesia or deep sedation increased markedly from 37.8% to 82.8% of procedures (P < 0.0001). CONCLUSIONS: This is the largest survey of EUS practice in the USA. Evaluation of the pancreas accounts for approximately 40% of the indications for EUS. Use of EUS increased over the study period, and the proportion carried out with deep sedation or general anesthesia also increased. These data may have implications regarding the number of endosonographers who should be trained, as well as cost issues pertaining to increasing use of anesthesia providers and same-day ERCP.

Potential application of interventional endoscopic ultrasonography for the treatment of esophageal and gastric varices.

Interventional endoscopic ultrasonography (EUS) has been developed mainly for the treatment of pancreaticobiliary disorders (e.g. cyst drainage for pancreatic pseudocysts, biliary drainage for malignant biliary obstruction, and celiac plexus neurolysis). Recently, the application of interventional EUS has been expanded to a new field, the treatment of gastrointestinal varices. There have been several studies examining this new technique for the treatment of esophageal and gastric varices. In the present review, we have summarized the current status of interventional EUS for the treatment of esophageal and gastric varices (e.g. EUS-guided coil deployment for gastric varices) and clarified the clinical feasibility of this procedure.

Current status of tissue harmonic imaging in endoscopic ultrasonography (EUS) and EUS-elastography in pancreatobiliary diseases.

Endoscopic ultrasonography (EUS) has high spatial and contrast resolution, and is thought to be one of the most reliable and efficient diagnostic modalities for pancreatobiliary diseases. Recent progress in EUS, especially in the development of the electronic scanning method, has enabled the application of several utilities and software of a high-end transabdominal ultrasound apparatus as an image-enhanced EUS. Tissue harmonic imaging (THI) is a novel US acquisition method that provides better US images by using second harmonic signals. The potential advantages of THI are improved lateral resolution, reduced side lobe artifact and an increased signal-to-noise ratio. EUS-elastography is another novel technique that provides information about the distributed pattern of tissue hardness. Clinical benefits of EUS-elastography for the differential diagnosis of pancreatic tumors and the evaluation of pancreatic fibrosis have been reported. It is necessary to develop a unified and objective method of imaging and analysis to increase the use of EUS-elastography in the future.

Digestive Disease Week (DDW) 2015: Pancreaticobiliary update.

This update critiques the key abstracts relevant to endoscopic evaluation or interventions in pancreatic and biliary diseases that were presented at Digestive Disease Week (DDW) 2015. We selected 20 abstracts based on their clinical significance, relevance to endoscopic practice and impact on patient management.

Contrast-enhanced harmonic endoscopic ultrasonography for pancreatobiliary diseases.

The combination of second-generation ultrasound contrast agents and an endoscopic ultrasonography (EUS) system with a broad-band transducer has allowed contrast-enhanced harmonic imaging in the field of EUS. In contrast-enhanced harmonic EUS (CH-EUS), diffuse homogeneous enhancement is obtained in normal parenchyma of the pancreas. The bile duct and pancreatic duct are depicted as non-enhanced ductal structures with strong contrast in comparison to the surrounding parenchyma. CH-EUS identifies pancreatic adenocarcinomas as solid lesions exhibiting hypo-enhancement with a sensitivity and specificity of 88-96% and 88-94%, respectively. In particular, 80-100% of false-negative cases in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are correctly classified by CH-EUS, suggesting CH-EUS complements EUS-FNA. Moreover, CH-EUS improves depiction of some subtle lesions in conventional EUS, thus facilitating EUS-FNA. For quantitative perfusion analysis, a time-intensity curve (TIC) for the region of interest can be generated during CH-EUS. The maximum intensity gain and the echo intensity reduction rate from the peak at 1 min obtained by TIC can be used for differentiation of pancreatic adenocarcinoma from other tumors. CH-EUS is also useful for differentiation of invasive intraductal papillary mucinous neoplasms (IPMN) from non-invasive IPMN, identification of malignant lesions in the gallbladder, and T- and N-staging of pancreatobiliary tumors.

Endoscopic approaches for the diagnosis of autoimmune pancreatitis.

Autoimmune pancreatitis (AIP) is characterized by diffuse pancreatic enlargement and irregular narrowing of the main pancreatic duct (MPD). Immunoglobulin (Ig)G4-related sclerosing cholangitis (IgG4-SC) associated with AIP frequently appears as a bile duct stricture. Therefore, it is important to differentiate AIP and IgG4-SC from pancreatic cancer and cholangiocarcinoma or primary sclerosing cholangitis, respectively. Endoscopy plays a central role in the diagnosis of AIP and IgG4-SC because it provides imaging of the MPD and bile duct strictures as well as the ability to obtain tissue samples for histological evaluations. Diffuse irregular narrowing of MPD on endoscopic retrograde cholangiopancreatography (ERCP) is rather specific to AIP, but localized narrowing of the MPD is often difficult to differentiate from MPD stenosis caused by pancreatic cancer. A long stricture (>1/3 the length of the MPD) and lack of upstream dilatation from the stricture (<5 mm) might be key features of AIP on ERCP. Some cholangiographic features, such as segmental strictures, stric tures of the lower bile duct, and long strictures with prestenotic dilatation, are more common in IgG4-SC than in cholangiocarcinoma. Endoscopic ultrasonography (EUS) reveals diffuse hypoechoic pancreatic enlargement, sometimes with hypoechoic inclusions, in patients with AIP. In addition, EUS-elastography and contrast-enhanced harmonic EUS have been developed with promising results. The usefulness of EUS-guided fine-needle aspiration has been increasingly recognized for obtaining adequate tissue samples for the histological diagnosis of AIP. Further improvement of endoscopic procedures and devices will contribute to more accurate diagnosis of AIP and IgG4-SC.

Ring-enhancement pattern on contrast-enhanced CT predicts adenosquamous carcinoma of the pancreas: a matched case-control study.

OBJECTIVES: Adenosquamous carcinoma of the pancreas (ASC) is a rare malignant neoplasm of the pancreas, exhibiting both glandular and squamous differentiation. However, little is known about its imaging features. This study examined the imaging features of pancreatic ASC. METHODS: We evaluated images of contrast-enhanced computed tomography (CT) and endoscopic ultrasonography (EUS). As controls, solid pancreatic neoplasms matched in a 2:1 ratio to ASC cases for age, sex and tumor location were also evaluated. RESULTS: Twenty-three ASC cases were examined, and 46 solid pancreatic neoplasms (43 pancreatic ductal adenocarcinomas, two pancreatic neuroendocrine tumors and one acinar cell carcinoma) were matched as controls. Univariate analysis demonstrated significant differences in the outline and vascularity of tumors on contrast-enhanced CT in the ASC and control groups (P < 0.001 and P < 0.001, respectively). A smooth outline, cystic changes, and the ring-enhancement pattern on contrast-enhanced CT were seen to have significant predictive powers by stepwise forward logistic regression analysis (P = 0.044, P = 0.010, and P = 0.001, respectively). Of the three, the ring-enhancement pattern was the most useful, and its predictive diagnostic sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of ASC were 65.2%, 89.6%, 75.0% and 84.3%, respectively. CONCLUSIONS: These results demonstrate that presence of the ring-enhancement pattern on contrast-enhanced CT is the most useful predictive factor for ASC.