Ryo Igarashi

Usefulness of endoscopic ultrasound-guided fine-needle aspiration with a forward-viewing and curved linear-array echoendoscope for small gastrointestinal subepithelial lesions

Background and study aims: It is difficult to perform endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of small gastrointestinal (GI) subepithelial lesions (SELs) approximately 10 mm in diameter. This study was undertaken to evaluate the feasibility, safety, and diagnostic ability of EUS-FNA with a forward-viewing and curved linear-array echoendoscope (FVCLA-ES) that has a cap for small SELs. Patients and methods: The study enrolled 8 patients who had small upper GI SELs approximately 10 mm in diameter. To fix the SELs during FNA, a cap device was attached to the scope tip. Results: The mean (standard deviation [SD]) diameter of the SELs was 10.6 mm (2.94). Even small lesions were well targeted for FNA when the FVCLA-ES with a cap device was used. The mean (SD) number of passes was 4.6 (1.59). Adequate samples were obtained from 7 patients (87.5 %) – in 6 (75 %) for cytology and in 4 (50 %) for histologic examination with immunohistochemical (IHC) staining. No complication occurred. Gastrointestinal stromal tumor (GIST) in 2 patients and leiomyoma in 2 patients were definitively diagnosed with IHC staining. Conclusions: EUS-FNA with an FVCLA-ES that has a cap device is feasible and safe. This technique is expected to contribute to histologic diagnosis, even in small SELs.

Rare condition of needle tract seeding after EUS-guided FNA for intraductal papillary mucinous carcinoma

Background and study aims: We report on a 75-year-old man who was admitted due to pancreatic cystic lesion accompanied by a solid mass with liver metastasis. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed on the solid mass, and pathological findings revealed the lesion to be an adenocarcinoma diagnosed as intraductal papillary mucinous carcinoma (IPMC). Approximately 3 months after, a cystic subepithelial lesion appeared in the posterior gastric wall where the EUS-FNA had been performed. We performed EUS-FNA again, which revealed that the cystic mass was IPMC with pathology similar to the original lesion. This is a rare case demonstrating needle tract seeding of EUS-FNA for IPMC.

Efforts to improve the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration for pancreatic tumors.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is widely used to obtain a definitive diagnosis of pancreatic tumors. Good results have been reported for its diagnostic accuracy, with high sensitivity and specificity of around 90%; however, technological developments and adaptations to improve it still further are currently underway. The endosonographic technique can be improved when several tips and tricks useful to overcome challenges of EUS-FNA are known. This review provides various techniques and equipment for improvement in the diagnostic accuracy in EUS-FNA.

Clinical effects of eosinophilic esophagitis observed using endoscopic ultrasound

A 50-year-old woman was referred to our hospital for dysphagia and several episodes of esophageal food impaction during the prior three months. Complete blood count and basic biochemical tests were normal. No eosinophilia was found. Esophagogastroduodenoscopy (EGD) revealed the presence of concentric rings (esophageal “trachealization”) and stenosis along the middle and distal esophagus. Endoscopic ultrasound (EUS) showed circumferential thickening of all layers in the same part. Cytopathologic evaluation of a specimen obtained by endoscopic biopsy of the thickened area in the distal esophagus showed eosinophilic infiltration (20 eosinophils per high-powered field). She was diagnosed as having eosinophilic esophagitis (EoE). Topical steroid therapy was started. A tendency of dysphagia for relief and improvement of characteristic EGD findings began early, but wall thickening in EUS remained. Past reports of the related literature have described that thickness of submucosa and muscularis propria remained after therapy, although significant reduction in the mucosal thickness was provided by short-term steroid therapy. One explanation for early relapse is insufficient reduction in the submucosa and muscularis propria. Consequently, our patient was given steroids until thickness on EUS improved. EUS is regarded as useful for evaluating the curative effect in patients with EoE.

Early diagnosis of chronic pancreatitis: understanding the factors associated with the development of chronic pancreatitis

The prognosis of advanced chronic pancreatitis (CP) is poor with the mortality rate approximately two-fold higher than the general population according to a survey of the prognosis of CP.　From this standpoint, the concept of early CP was propagated in Japan in 2009 to encourage the medical treatment for the earlier stages of CP.　That is, picking up the patients suspicious for early CP and then providing medical treatment for them are very important not only for patients, but also for health care economics.　In this review, we described some potential factors associated with the development of CP (alcohol, smoking, past history of acute pancreatitis, aging, gallstone, and gender) that are extremely important to discover patients with early-stage CP.

Significance of normal appearance on endoscopic ultrasonography in the diagnosis of early chronic pancreatitis

Background and Objectives: The Rosemont classification (RC) was developed as a consensus-based standard for the diagnosis of chronic pancreatitis (CP) by endoscopic ultrasonography (EUS), however, it is more complicated than the conventional scoring system. We have noticed that in the early stages of CP, it is not unusual to observe pancreas with abnormal appearance coexisting with the areas of normal parenchyma. The aim of this study was to investigate the validity of a “normal” pancreas appearance and to evaluate the usefulness of modified diagnostic criteria in comparison to the traditional EUS criteria and the RC. Patients and Methods: One hundred and seventy-seven patients who had undergone both EUS and endoscopic retrograde pancreatography (ERP) within 2 months were enrolled in the study, and patients with pancreatic cancer were excluded from the study. ERP findings were used as the gold standard for the diagnosis of CP. The EUS images obtained were classified according to both the RC and our new modified criteria. The latter includes an additional criterion to the modified traditional criteria: fine-reticular pattern (F-RP) was defined as a normal pancreatic parenchyma. We compared the accuracy between the new modified EUS criteria and the RC. Results: (1) Normal or equivocal findings on ERP were obtained for 132 patients; 113 patients had F-RP on EUS. In contrast, F-RP was found in only 6 out of 45 CP cases on ERP (P < 0.0001). (2) We investigated the diagnostic capability of our new criteria for endoscopic retrograde cholangiopancreatography normal/equivocal pancreas compared to the traditional criteria. In cases where fewer than two points were defined as normal, the incidence of normal pancreas was significantly higher based on the new criteria than on the traditional criteria (P = 0.002). (3) No significant differences were found between the new criteria and the RC across all ERP grades. Conclusion: Our new proposed “normal-added EUS criteria” for diagnosing CP was equivalent to the RC.

Validation of a realistic, simple, and inexpensive EUS-FNA training model using isolated porcine stomach

Background and study aims: Trainees are required to learn EUS-FNA using a model before working with a patient. The aim of the current study was to validate a new training model developed for EUS-FNA. Patients and methods: Several fresh chicken tenderloins were embedded as target lesions in the submucosal layer of an isolated porcine stomach. The stomach was fixed to a plate with nails, and was placed in a tub filled with water. The primary endpoint was feasibility of the newly developed model for EUS-FNA training, evaluated as follows: 1) visualization of the target lesion with blinding for lesion location; 2) penetrability of the needle; 3) sampling rate of macroscopic specimen; and 4) ROSE capability. Secondary endpoints were its durability and utility for multiple EUS-FNA procedures during EUS-FNA training, and the ease and cost of preparing the model. Results: Six endoscopists (1 expert, 5 trainees) attempted EUS-FNA procedures using this model. The target lesion could be identified clearly, and EUS-FNA could be performed with realistic resistance felt. In addition, rapid on-site evaluation could be easily achieved. Based on 10 needlings by each endoscopist, adequate specimens for histology could be macroscopically taken with an average 85 % success rate. Visibility and maneuverability were maintained throughout all needlings. Preparation time for this model was less than 30 minutes with a total cost of

Application of a silver coating on plastic biliary stents to prevent biofilm formation: an experimental study using electron microscopy

 22. Conclusions: An easy-to-use and inexpensive training model with a realistic feel of needling was created. This model can potentially enable beginners to practice safe and effective EUS-FNA procedures.

Agenesis of the Gallbladder in Monozygotic Twin Sisters

Background and study aims: Biliary stent dysfunction is mainly caused by biliary sludge that forms as a result of bacterial adherence and subsequent biofilm formation on the inner surface of the stent. Silver ions arewell known to have excellent antimicrobial activity against a wide range of microorganisms. In this study, we designed and constructed silver-coated plastic stent (PS) and investigated whether the silver coating prevented bacterial adherence and biofilm formation through the use of electron microscopy. Material and methods: The polyurethane PS with/without silver coating were prepared in 6-inch segments. The silver-based antimicrobial agents were electrostatically applied onto the stent surface. The stents were then immersed for 5 weeks in infected human bile juice obtained from a patient with cholangitis, and electron microscopy was used to investigate the ability of the modified PS to prevent bacterial adherence and biofilm formation. Results: The bacterial flora did not change before and after immersion of stents in both the group with and without silver coating. Electron microscopic observation revealed meshwork-like structures around the bacteria, characteristic of biofilm-forming bacteria, in all stents from the control group (6/6, 100 %). On the other hand, a limited number of bacteria were observed in all stents in the silver-coated group, and no apparent biofilm formation was observed (0/6, 0 %). Conclusions: The significance of the findings from our study is the ability of silver-coated PS to prevent biofilm formation on the stent surface, which results in the prevention of stent occlusion.

An experimental study to assess the best maneuver when using a reverse side-bevel histology needle for EUS-guided fine-needle biopsy

Agenesis of the gallbladder, a rare anomaly, is generally regarded as an organogenic failure. Several reports suggest that this congenital defect is inherited but that supposition remains controversial. We described agenesis of the gallbladder in identical twins. A 21-year-old female presented with a history of acute pain in the epigastrium and right hypochondrium. Various imaging modalities showed “gallbladder agenesis.” Moreover, her older identical twin sister had also no visualized gallbladder in imaging modalities. This case report strongly suggested that agenesis of the gallbladder would be caused by a genetic abnormality.