Role of macroscopic on-site evaluation of endoscopic ultrasoundguided fine-needle aspiration/biopsy:Results of a multicentric prospective study

BACKGROUND The concept of macroscopic on-site evaluation(MOSE)was introduced in 2015 when the endoscopist observed better diagnostic yield when the macroscopically visible core on MOSE was superior to 4 mm.Recent studies suggest that MOSE by the endoscopist may be an excellent alternative to rapid on-site evaluation,and some classi-fications have been published.Few studies have assessed the adequacy of histologic cores in MOSE during endoscopic ultrasound-guided fine-needle aspiration/biopsy(EUS-FNA/FNB).AIM To evaluate the performance of MOSE during EUS-FNA/FNB.METHODS This multicentric prospective study was conducted in 16 centers in 3 countries(Egypt,Iraq,and Morocco)and included 1108 patients with pancreatic,biliary,or gastrointestinal pathology who were referred for EUS examination.We prospectively analyzed the MOSE in 1008 patients with available histopathological reports according to 2 classifications to determine the adequacy of the histological core samples.Data management and analysis were performed using a Statistical Package for Social Sciences(SPSS)version 27.RESULTS A total of 1074 solid lesions were biopsied in 1008 patients with available cytopathological reports.Mean age was 59 years,and 509 patients(50.5%)were male.The mean lesion size was 38 mm.The most frequently utilized needles were FNB-Franseen(74.5%)and 22 G(93.4%),with a median of 2 passes.According to 2 classifications,618 non-bloody cores(61.3%)and 964 good samples(95.6%)were adequate for histological evaluation.The overall diagnostic yield of cytopathology was 95.5%.The cytological examination confirmed the diagnosis of malignancy in 861 patients(85.4%),while 45 samples(4.5%)were inconclusive.Post-procedural adverse events occurred in 33 patients(3.3%).Statistical analysis showed a difference between needle types(P=0.035)with a high sensitivity of FNB(97%).The analysis of the relationship between the MOSE-score and the final diagnosis showed a significant difference between the different scores of the MOSE(P<0.001).CONCLUSION MOSE is a simple method that allows endoscopists to increase needle passes to improve sample quality.There is significantly higher FNB sensitivity and cytopathology diagnostic yield with good MOSE cores.

Fine-needle aspiration technique under endoscopic ultrasound guidance:A technical approach for RNA profiling of pancreatic neoplasms

BACKGROUND Early diagnosis of pancreatic ductal adenocarcinoma(PDAC)has been a longstanding challenge.The prognosis of patients with PDAC depends on the stage at diagnosis.It is necessary to identify biomarkers for the detection and differentiation of pancreatic tumors and optimize PDAC sample preparation procedures for DNA and RNA analysis.Most molecular studies are done using paraffin-embedded blocks;however,the integrity of DNA and RNA is often compromised in this format.Moreover,RNA isolated from human pancreatic tissue samples is generally of low quality,in part,because of the high concentration of endogenous pancreatic RNAse activity present.AIM To assess the potential of endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA)to obtain specimens from pancreatic neoplasms for subsequent RNA molecular profiling,including next-generation sequencing(NGS).METHODS Thirty-four EUS-FNA samples were included in this study:PDAC(n=15),chronic pancreatitis(n=5),pancreatic cysts(n=14),mucinous cysts(mucinous cystic neoplasia/intraductal papillary mucinous neoplasia)n=7,serous cystic neoplasms n=5,and pseudocysts n=2.Cyst material consisted of cyst fluid and cyst wall samples obtained by through-the-needle biopsy(TTNB).Samples were stored at -80℃ until analysis.RNA purity(A260/230,A260/280 ratios),concentration,and integrity(RIN)were assessed.Real-time polymerase chain reaction was conducted on all samples,and small RNA libraries were prepared from solid mass samples.RESULTS RNA was successfully extracted from 29/34(85%)EUS-FNA samples:100% pancreatic adenocarcinoma samples,100% chronic pancreatitis samples,70% pancreatic fluid cyst samples,and 50%TTNB samples.The relative expression of GAPDH and HPRT were obtained for all successfully extracted RNA samples(n=29)including lowquality RNA specimens.Low concentration and nonoptimal RIN values(no less than 3)of RNA extracted from EUS-FNA samples did not prevent NGS library preparation.The suitability of cyst fluid samples for RNA profiling varied.The quality of RNA extracted from mucinous cyst fluid had a median RIN of 7.7(5.0-8.2),which was compatible with that from solid neoplasms[6.2(0-7.8)],whereas the quality of the RNA extracted from all fluids of serous cystic neoplasms and TTNB samples had a RIN of 0.CONCLUSION The results demonstrate the high potential of EUS-FNA material for RNA profiling of various pancreatic lesions,including low-quality RNA specimens.

Optimizing electrocoagulation process for the treatment of biodiesel wastewater using response surface methodology

The production of biodiesel through a transesterification method produces a large amount of wastewater that contains high levels of chemical oxygen demand （COD） and oil and grease （O＆G）. Currently, flotation is the conventional primary treatment for O＆G removal prior to biological treatments. In this study, electrocoagulation （EC） was adopted to treat the biodiesel wastewater. The effects of initial pH, applied voltage, and reaction time on the EC process for the removal of COD, O＆G, and suspended solids （SS） were investigated using one factor at a time experiment. Furthermore, the Box-Behnken design, an experimental design for response surface methodology （RSM）, was used to create a set of 15 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the pollutant removals. The experimental results show that EC could effectively reduce COD, O＆G, and SS by 55.43%, 98.42%, and 96.59%, respectively, at the optimum conditions of pH 6.06, applied voltage 18.2 V, and reaction time 23.5 min. The experimental observations were in reasonable agreement with the modeled values.

Treatment of tannery wastewater by electrocoagulation

Treatment of tannery wastewater by electrocoagulation with low cell current （≤ 1A） and soluble electrodes （mild steel electrodes and aluminum electrodes） was studied. Compared with aluminum electrodes, mild steel electrodes were more effective for the removal of sulfide, with a removal efficiency of over 90%. But during the treatment process, black color precipitate typical to iron（Ⅱ） sulfides was produced. While aluminum electrodes were effective to eliminate the colority of the effluent, the removal efficiency of sulfide was lower than 12%. The mechanisms of the removal of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority with the two soluble electrodes （mild steel and aluminum electrodes） were discussed in detail. In order to exert the predominance of diffenent types of electrodes, the tannery wastewater was treated using mild steel electrodes first followed by the filter and finally by the aluminum electrodes, the elimination rates of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority were 68.0%, 43.1%, 55.1%, 96.7% and 84.3%, respectively, with the initial concentrations 2413.1 mg/L, 223.4 mg/L, 1000.4 mg/L, 112.3 mg/L and 256 dilution times, respectively. The absorbance spectra and energy consumption during electrocoagulation process were also discussed.

An alternative treatment process for upgrade of petroleum refinery wastewater using electrocoagulation

An electrocoagulation treatment process was developed for treatment and upgrade of petroleum refinery effluent （wastewater）, instead of the conventional methods, which can consume higher amounts of chemicals and produce larger amounts of sludge. The effect of the operation parameters, such as current density, initial pH, anode material, anode dissolution, energy consumption and electrolysis time, on treatment efficiency was investigated. The experimental results showed that the effluent can be effectively treated under optimal conditions. Fourier transform infrared （FTIR） analysis of the effluent, and scanning electron microscopy （SEM） coupled with energy dispersive analysis of X-rays （EDAX） of the sludge produced, revealed that the unwanted pollutants can be eliminated. The electrocoagulation treatment process was assessed by using the removal efficiency of chemical oxygen demand （COD）, total suspended solids （TSS）, and the general physicochemical characteristics of wastewater, and the results showed that the electrocoagulation is an efficient process for recycling of petroleum wastewater; it is faster and provides better quality of treated water than the conventional methods.

Risk factors of electrocoagulation syndrome after esophageal endoscopic submucosal dissection

AIM To investigate post endoscopic submucosal dissection electrocoagulation syndrome(PEECS) of the esophagus.METHODS We analyzed 55 consecutive cases with esophageal endoscopic submucosal dissection for superficial esophageal squamous neoplasms at a tertiary referral hospital in South Korea. Esophageal PEECS was defined as "mild" meeting one of the following criteria without any obvious perforation: fever(≥ 37.8 ℃), leukocytosis(> 10800 cells/μl), or regional chest pain more than 5/10 points as rated on a numeric pain intensity scale. The grade of PEECS was determined as "severe" when meet two or more of above criteria.RESULTS We included 51 cases without obvious complications in the analysis. The incidence of mild and severe esophageal PEECS was 47.1% and 17.6%, respectively. Risk factor analysis revealed that resected area, procedure time, and muscle layer exposure were significantly associated with PEECS. In multivariate analysis, a resected area larger than 6.0 cm^2(OR = 4.995, 95%CI: 1.110-22.489, P = 0.036) and muscle layer exposure(OR = 5.661, 95%CI: 1.422-22.534, P = 0.014) were independent predictors of esophageal PEECS. All patients with PEECS had favorable outcomes with conservative management approaches, such as intravenous hydration or antibiotics.CONCLUSION Clinicians should consider the possibility of esophageal PEECS when the resected area exceeds 6.0 cm^2 or when the muscle layer exposure is noted.

Endoscopic ultrasound-guided fine-needle aspiration cytology diagnosis of solid pseudopapillary tumor of the pancreas: A case report and literature review

We describe the clinical, imaging and cytopathological features of solid pseudopapillary tumor of the pancreas (SPTP) diagnosed by endoscopic ultrasound- guided (EUS-guided) fine-needle aspiration (FNA). A 17-year-old woman was admitted to our hospital with complaints of an unexplained episodic abdominal pain for 2 mo and a short history of hypertension in the endocrinology clinic. Clinical laboratory examinations revealed polycystic ovary syndrome, splenomegaly and low serum amylase and carcinoembryonic antigen (CEA) levels. Computed tomography (CT) analysis revealed a mass of the pancreatic tail with solid and cystic consistency. EUS confirmed the mass, both in body and tail of the pancreas, with distinct borders, which caused dilation of the peripheral part of the pancreatic duct (major diameter 3.7 mm). The patient underwent EUS-FNA. EUS-FNA cytology specimens consisted of single cells and aggregates of uniform malignant cells, forming microadenoid structures, branching, papillary clusters with delicate fibrovascular cores and nuclear overlapping. Naked capillaries were also seen. The nuclei of malignant cells were round or oval, eccentric with fine granular chromatin, small nucleoli and nuclear grooves in some of them. The malignant cells were periodic acid Schiff (PAS)-Alcian blue (+) and immunocytochemically they were vimentin (+), CA 19.9 (+), synaptophysin (+), chromogranin (-), neuro-specific enolase (-), a1- antitrypsin and a1-antichymotrypsin focal positive. Cytologic findings were strongly suggestive of SPTP. Biopsy confirmed the above cytologic diagnosis. EUS- guided FNA diagnosis of SPTP is accurate. EUS findings,cytomorphologic features and immunostains of cell block help distinguish SPTP from pancreatic endocrine tumors, acinar cell carcinoma and papillary mucinous carcinoma.

High performance electrocoagulation process in treating palm oil mill effluent using high current intensity application

Electrocoagulation process using high current intensity to treat palm oil mill effluent(POME) was investigated in this study.Various operating parameters such as electrolysis time, inter-electrode distance and initial pH were carried out to determine the efficient process condition on the removal of chemical oxygen demand(COD),biological oxygen demand(BOD) and suspended solids(SS).The highest treatment was achieved at 50 min with the removal efficiencies for COD, BOD and SS obtained as 85%, 83%, and 84%, respectively.More than 50 min treatment showed the fluctuated trends of removal efficiencies which can be considered insignificant.The application of higher current resulted in higher removals of organics while the gas bubbles also assisted in removing the pollutant particles by floatation.In an inter-electrode distance study, the removal efficiency decreased when inter-electrode distance was either higher or lower than 10 mm due to the increase of solution resistance and the decrease of anode active surface area.In initial pH study, it was found that high removal efficiencies were achieved in slightly acidic POME sample rather than in neutral or basic condition.An electrocoagulation process by using the optimum operating parameters was able to remove COD, BOD and SS up to 95%, 94% and 96% respectively.The experimental results confirm that application of high current intensity in electrocoagulation provided high treatment efficiency at a reduced reaction time.

Phenol Removal from Aqueous Solutions by Electrocoagulation Technology Using Iron Electrodes:Effect of Some Variables

The aim of this study was to determine the effect of electrocoagulation technology using iron electrodes on phenol removal in aqueous solutions. The removal of phenol was investigated in terms of various parameters, namely, current density, phenol and NaCl concentration, pH, and alginic acid concentration. The results showed that the removal efficiency of phenol increased with increasing the current density, pH and NaCl concentration, whereas it was inversely associated with initial concentration of phenol and alginic acid concentration. According to the results, electrocoagulation is a promising process for treatment of wastewater containing high concentration of phenol.

Rapid on-site evaluation of endoscopic-ultrasound-guided fine-needle aspiration diagnosis of pancreatic masses

Endoscopic ultrasound (EUS) has become an essential tool for the study of pancreatic diseases. Specifically, EUS plays a pivotal role evaluating patients with a known or suspected pancreatic mass. In this setting, differential diagnosis remains a clinical challenge. EUS-guided fine-needle aspiration (FNA) and fine-needle biopsy (FNB) have been proven to be safe and useful tools in this setting. EUS-guided FNA and FNB, by obtaining cytological and/or histological samples, are able to diagnose pancreatic lesions with high sensitivity and specificity. In this context, several methodological features, trying to increase the diagnostic yield of EUS-guided FNA and FNB, have been evaluated. In this review, we focus on the role of rapid on-site evaluation (ROSE). From data reported in the literature, ROSE may increase diagnostic yield of EUS-FNA specimens by 10%-30%, and thus, diagnostic accuracy. However, we should point out that many recent studies have reported adequacy rates of &#x0003e; 90% without ROSE, indicating that, perhaps, at high-volume centers, ROSE may not be indispensable to achieve excellent results. The use of ROSE can be considered important during the learning curve of EUS-FNA, and also in hospital with diagnostic accuracy rates &#x0003c; 90%.

High total Joule heat increases the risk of post-endoscopic submucosal dissection electrocoagulation syndrome after colorectal endoscopic submucosal dissection

BACKGROUND We hypothesized that thermal damage accumulation during endoscopic submucosal dissection(ESD)causes the pathogenesis of post-ESD electrocoagulation syndrome(PECS).AIM To determine the association between Joule heat and the onset of PECS.METHODS We performed a retrospective cohort study in patients who underwent colorectal ESD from May 2013 to March 2021 in Japan.We developed a novel device that measures swift coagulation time with a sensor adjacent to the electrosurgical coagulation unit foot switch,which enabled us to calculate total Joule heat.PECS was defined as localized abdominal pain(visual analogue scale≥30 mm during hospitalization or increased by≥20 mm from the baseline)and fever(temperature≥37.5 degrees or white blood cell count≥10000μ/L).Patients exposed to more or less than the median Joule heat value were assigned to the high and low Joule heat groups,respectively.Statistical analyses included Mann-Whitney U and chisquare tests and logistic regression and receiver operating characteristic curve(ROC)analyses.RESULTS We evaluated 151 patients.The PECS incidence was 10.6%(16/151 cases),and all patients were followed conservatively and discharged without severe complications.In multivariate analysis,high Joule heat was an independent PECS risk factor.The area under the ROC curve showing the correlation between PECS and total Joule heat was high[0.788(95%confidence interval:0.666-0.909)].CONCLUSION Joule heat accumulation in the gastrointestinal wall is involved in the onset of PECS.ESD-related thermal damage to the peeled mucosal surface is probably a major component of the mechanism underlying PECS.

Optimization and mechanisms analysis of indigo dye removal using continuous electrocoagulation

Electrocoagulation(EC) is among the most effective techniques that remove color and decontaminate effluent.Coagulants are delivered in situ by anode corrosion.In this research,indigo dye removal using iron electrodes in continuous electrocoagulation process and the responsible species for decolorization were investigated.The Response Surface Methodology(RSM) was used to optimize the process parameters.The finding in this study shows that at fixed conductivity at 15,000 μS·cm^(-1) the neutral conditions(pH from 6 to 8),the low absorbance,the low flow rate and the high voltage level enhance the color removal efficiency.The high R~2 value of 97.8% and ANOVA analyses show a good correlation between the experimental and predicted results.Under the optimum conditions,which are pH of 7.5, solution concentration of 60 mg·L^(-1), inlet flow rate of 2 L·min^(-1) and voltage of 47 V, the predicted decolorization of 94.083% was achieved at 93.972% with a total cost of 0.0927 USD·m^(-3) of treated effluent.At the optimum pH(7.5),the zeta potential value(-4 mV) of the effluent during EC match with the one of iron Ⅲ hydroxide.The dye removal is ensured thanks to physical adsorption and flocculation.The results exposed in this work prove that the continuous electrocoagulation process could be successfully used for indigo dye removal at industrial scale.

Endoscopic ultrasound-guided fine-needle aspiration cytology in pancreaticobiliary carcinomas:diagnostic efficacy of cell-block immunocyto-chemistry

BACKGROUND： Endoscopic ultrasound-guided fine-needle aspiration cytology was demonstrated to be a useful tool for the diagnosis and staging of pancreaticobiliary neoplastic le- sions. Nonetheless, the diagnostic value of this procedure may be limited by low cellularity of the specimen, contamination of intestinal cells and unfeasibility of ancillary immunocy- tochemical procedures. The present study was to evaluate its usefulness in the diagnosis of neoplastic lesions.

Application of Electrocoagulation and Electrolysis on the Precipitation of Heavy Metals and Particulate Solids in Washwater from the Soil Washing

Soil washing, ex situ mechanical technique, is one of the few permanent treatment alternatives to remove metal contaminants from soils by employing physical separation based on mineral processing technologies to remove discrete particles or metal-bearing particles and/or chemical extraction based on leaching or dissolving process to extract the metals from the soils into an aqueous solution. However, washwater remained from soil washing process contains discrete particulate particles along with heavy metals as solution phase to be treated separately, as well as this process can produce large amount of sludge that requires further treatment, slow metal precipitation, poor settling, the aggregation of metal precipitates. Electrical treatments including electrocoagulation and electrolysis can be effective in removing these substances from washwater. This paper reviews the theoretical models in applying electrocoagulation and electrolysis to remove heavy metals and discrete particulate particles in washwater by examining and comparing the status of washwater treatment technologies which have been undertaken, mostly in the US and EU for the period 1990-2012.

Incidents and adverse events of endoscopic ultrasoundguided fine-needle aspiration for pancreatic cystic lesions

AIM To evaluate the diagnostic value and safety mainly regarding incidents of endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA) for pancreatic cystic lesions(PCLs).METHODS A total of 150 consecutive patients with suspected PCLs were prospectively enrolled from April 2015 to November 2016. We finally enrolled 140 patients undergoing EUS-FNA. We compared the diagnostic accuracy of EUS-FNA and pathological diagnosis, which is regarded as the gold standard, for PCLs. Patients undergoing EUS-FNA at least 1 wk preoperatively were monitored for incidents and adverse events to evaluate its safety.RESULTS There were 88(62.9%) women and 52(37.1%) men among 140 patients, with a mean age of 50.1(± 15.4) years. There were 67 cysts located in the head/uncinate of the pancreas and 67 in the body/tail, and 6 patients had at least 1 cyst in the pancreas. There were 75 patients undergoing surgery and 55 undergoing EUS-FNA with interval at least 1 wk before other operations, with 3 patients undergoing the procedure twice. The accuracy of EUS-FNA in differentiating benign and malignant lesions was 97.3%(73/75), while the accuracy of characterizing PCL subtype was 84.0%(63/75). The incident rate was 37.9%(22/58), whereas only 1 AE was observed in 58 cases.CONCLUSION EUS-FNA is effective and safe for diagnosis of PCLs, however procedure-related incidents are common. Caution should be taken in patients undergoing EUSFNA.

Remediation of Pulp and Paper Industry Effluent Using Electrocoagulation Process

Electrocoagulation of pulp and paper industry effluent with SS-304 electrode has been carried out under varying process variable such as pH, current density, time and dose of electrolyte to find out the optimum conditions. Maximum reduction efficiency of Chemical Oxygen Demand (COD) 82% and color more than 99% from pulp and paper industry wastewater at the following conditions pH = 7, current density = 24.80 mA/cm2 time = 40 min and dose of electrolytes = 1.0 g/L. Moreover, effects of electrolytes dosage on electricity consumption were observed and found to be that NaCl is better in comparison of Na2SO4 in respect of lower down the electricity consumption. But application of NaCl causes the formation of hazardous compounds as secondary pollutants within treated water. Therefore, Na2SO4 could be a potent replacement of NaCl to enhance the conductivity of paper industry effluent treated by EC process. The treated water has been compared with standard of Central Pollution control board (CPCB) and World Health organization, and found to be suitable for the reuse in irrigation.

Slow-pull and different conventional suction techniques in endoscopic ultrasound-guided fine-needle aspiration of pancreatic solid lesions using 22-gauge needles

AIM To evaluate the cytological diagnostic capacity and sample quality of the slow-pull technique and compare them with different suction techniques.METHODS From July 2010 to December 2015, 102 patients with pancreatic solid lesions who underwent endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA) with 22-gauge needles were retrospectively evaluated. EUS-FNA diagnosis was based on a cytological examination, and final diagnosis was based on a comprehensive standard of cytological diagnosis, surgical pathology and clinical or imaging follow-up. Cytological specimens were characterized for cellularity and blood contamination. The cytological diagnostic capacity and sample quality of the slow-pull technique and suction techniques with 5-m L/10-m L/20-m L syringes were analyzed.RESULTS Of all of the EUS-FNA procedures, the slow-pull technique and suction techniques with 5-m L/10-m L/20-m L syringes were used in 31, 19, 34 and 18 procedures, respectively. There were significant differences between these four suction techniques in terms of cytological diagnostic accuracy(90.3% vs 63.2% vs 58.8% vs 55.6%, P = 0.019), sensitivity(88.2% vs 41.7% vs 40.0% vs 36.4%, P = 0.009) and blood contamination(score ≥ 2 for 29.0% vs 52.6% vs 70.6% vs 72.2%, P = 0.003). The accuracy and sensitivity of the slow-pull technique were significantly higher than those of the suction techniques using 5-m L(P = 0.03, P = 0.014), 10-m L(P = 0.005; P = 0.006) and 20-mL syringes(P = 0.01, P = 0.01). Blood contamination was significantly lower in the slow-pull technique than in the suction techniques with 10-m L(P = 0.001) and 20-mL syringes(P = 0.007).CONCLUSION The slow-pull technique may increase the cytological diagnostic accuracy and sensitivity with slight blood contamination during EUS-FNA when using 22-gauge needles for solid pancreatic masses.

Ecofriendly Remediation of Pulp and Paper Industry Wastewater by Electrocoagulation and Its Application in Agriculture

In the present study pulp and paper industry effluent was treated with the help of aluminum electrode using electrocoagulation (EC) process with feasible sludge management. The influences of pH, time, current density and electrolytes dose were investigated and optimum conditions were established to reduce the maximum amount of Chemical Oxygen Demand (COD) and color. At optimum conditions 70% of COD and 98% of color were removed. Additionally, the behavior of electrolytes (NaCl and Na2SO4) was determined;it has shown that Na2SO4 results in the generation of less secondary pollutants than that NaCl and thereby could be used as better replacement in paper industries for electrocoagulation mediated treatment of wastewater. The residual amount of operational parameters in EC treated water was compared to the World Health Organization (WHO) and Central Pollution Control Board (CPCB) of India. It was found to be safe for utilization in irrigation. Furthermore, sludge produced during the EC process has been analyzed for physicochemical characteristics. To understand the physical and elemental phases of sludge, the analytical technique such as field emission electron microscope coupled with energy dispersive spectroscopy has been used to find out the possible management alternative.

Influence of the safety and diagnostic accuracy of preoperative endoscopic ultrasound-guided fine-needle aspiration for resectable pancreatic cancer on clinical performance

AIM: To evaluate the safety and diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in a cohort of pancreatic cancer patients.

Role of preoperative endoscopic ultrasound-guided fine-needle tattooing of a pancreatic head insulinoma

Although insulinomas are rare, they are the most com-mon pancreatic neuroendocrine tumor, with an inci-dence of four cases per million population. Insulinomas are generally benign indolent intrapancreatic tumors. Surgical resection remains the main option for treat-ment. However, up to 67% of a pancreatic head insu-linomas are nonpalpable, thus surgical resection of the nonplapable insulinoma in this area could become prob-lematic resulting in prolonged surgical time, increased risk of pancreatic duct injury and need for pancreati-coduodenectomy. Endoscopic ultrasound-guided fine- needle tattooing(EUS-FNT), has been shown to have a crucial role for localization of pancreatic body and tail lesions, facilitating laparoscopic distal pancreatectomyand helping surgeons identify the location of the tumor. EUS-FNT might have a role for preoperative localiza-tion of pancreatic head insulinomas which are likely to be nonpalpable. We report a case of preoperative EUS-FNT for localization of a nonplapable pancreatic head insulinoma. This report demonstrates that EUS-FNT of pancreatic head insulinomas may facilitate surgical resection, reduce operative time and decrease surgical complications.