Update on endoscopic ultrasound-guided liver biopsy

Endoscopic ultrasound guided liver biopsy(EUS-LB)has emerged as a minimally-invasive alternative to the traditional(percutaneous or transjugular)liver biopsy techniques for the diagnosis of liver parenchymal diseases.Potentially,EUS-LB combines the advantages of percutaneous and transjugular liver biopsy in addressing focused sampling in addition to measuring portal pressure.Additionally,EUS-LB facilitates access to both the lobes of the liver which is not considered with the traditional percutaneous liver biopsy.Multiple studies have compared EUS-LB with conventional liver biopsy and reported comparable diagnostic yield,increased acquisition of complete portal tracts,and longer specimen length as compared to the traditional approaches.EUS-LB is associated with lesser post-procedural pain and shorter recovery time,while providing lower risk of complications when compared to traditional liver biopsy.Innovations in needle types,needle sizes and suction techniques have aimed at further optimizing the EUS-LB technique.This review article updates current literature with focus on the variations in the technique and equipment used for EUS-LB,and compares EUS-LB with traditional methods of liver biopsy.

Endoscopic ultrasound-guided tissue acquisition for the diagnosis of focal liver lesion

In patients with liver tumors,the histopathology examination can assist in diagnosis,staging,prognosis,and therapeutic management strategy.Endoscopic ultrasound(EUS)-guided tissue acquisition using fine needle aspiration(FNA)or more newly fine needle biopsy(FNB)is a well-developed technique in order to evaluate and differentiate the liver masses.The goal of the EUS-FNA or EUS-FNB is to provide an accurate sample for a histopathology examination.Therefore,malignant tumors such as hepatocarcinoma,cholangiocarcinoma and liver metastasis or benign tumors such as liver adenoma,focal hyperplastic nodular tumors and cystic lesions can be accurately diagnosed using EUS-guided tissue acquisition.EUS-FNB using 19 or 22 Ga needle provide longer samples and a higher diagnostic accuracy in patients with liver masses when compared with EUS-FNA.Few data are available on the diagnostic accuracy of EUS-FNB when compared with percutaneously,ultrasound,computer tomography or transjugulary-guided liver biopsies.This review will discuss the EUS-guided tissue acquisition options in patients with liver tumors and its efficacy and safety in providing accurate samples.The results of the last studies comparing EUS-guided liver biopsy with other conventional techniques are presented.The EUS-guided tissue acquisition using FNB can be a suitable technique in suspected liver lesions in order to provide an accurate histopathology diagnosis,especially for those who require endoscopy.

Endo-hepatology: Why should we do endoscopic ultrasound-guided interventions to the liver that we could do through the skin?

Endoscopic ultrasound(EUS)-guided interventions on the liver such as diffuse biopsy and portal pressure gradient measurement are emerging as potential alternatives to percutaneous procedures.The purpose of this editorial was to address all the indications that could potentially make an EUS-guided approach a possible alternative to the percutaneous procedures with respect to the proce-dures that could join the EUS examination such as upper endoscopy for gastro-esophageal varices,pancreaticobiliary investigation with EUS,and other potential advantages in terms of patient safety.The issue of a holistic gastroenterologist approach was also discussed along with the potential for developing clinical research.

Endoscopic ultrasound-guided biliary drainage vs percutaneous transhepatic bile duct drainage in the management of malignant obstructive jaundice

BACKGROUND Malignant obstructive jaundice(MOJ)is a condition characterized by varying degrees of bile duct stenosis and obstruction,accompanied by the progressive development of malignant tumors,leading to high morbidity and mortality rates.Currently,the two most commonly employed methods for its management are percutaneous transhepatic bile duct drainage(PTBD)and endoscopic ultrasound-guided biliary drainage(EUS-BD).While both methods have demonstrated favorable outcomes,additional research needs to be performed to determine their relative efficacy.To compare the therapeutic effectiveness of EUS-BD and PTBD in treating MOJ.METHODS This retrospective analysis,conducted between September 2015 and April 2023 at The Third Affiliated Hospital of Soochow University(The First People’s Hospital of Changzhou),involved 68 patients with MOJ.The patients were divided into two groups on the basis of surgical procedure received:EUS-BD subgroup(n=33)and PTBD subgroup(n=35).Variables such as general data,preoperative and postoperative indices,blood routine,liver function indices,myocardial function indices,operative success rate,clinical effectiveness,and complication rate were analyzed and compared between the subgroups.RESULTS In the EUS-BD subgroup,hospital stay duration,bile drainage volume,effective catheter time,and clinical effect-iveness rate were superior to those in the PTBD subgroup,although the differences were not statistically significant(P>0.05).The puncture time for the EUS-BD subgroup was shorter than that for the PTBD subgroup(P<0.05).Postoperative blood routine,liver function index,and myocardial function index in the EUS-BD subgroup were significantly lower than those in the PTBD subgroup(P<0.05).Additionally,the complication rate in the EUS-BD subgroup was lower than in the PTBD subgroup(P<0.05).CONCLUSION EUS-BD may reduce the number of punctures,improve liver and myocardial functions,alleviate traumatic stress,and decrease complication rates in MOJ treatment.

The efficacy and safety of endoscopic ultrasound-guided fine-needle biopsy in gallbladder masses

Background: Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB) is a widely used modality for acquiring various target samples, but its efficacy in gallbladder masses is unknown. The aim of this retrospective study was to evaluate the efficacy and safety of EUS-FNB in patients with gallbladder masses. Methods: The study samples were composed of patients from March 2015 to July 2019 who needed to identify the nature of gallbladder masses through EUS-FNB. The outcomes of this study were the adequacy of specimens, diagnostic yields, technical feasibility, and adverse events of the EUS-FNB in gallbladder masses. Results: A total of 27 consecutive patients with a median age of 58 years were included in this study. The 22-gauge FNB needle was feasible in all lesions. The median follow-up period of the patients was 294 days. The specimens sufficient for diagnosis account for 89%(24/27) and 93%(25/27) in cytology and histology, respectively. The overall diagnostic yields for malignancy showed the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 95.45% [95% confidence interval(CI): 75.12%-99.76%], 100%(95% CI: 46.29%-10 0%), 10 0%(95% CI: 80.76%-100%), 83.33%(95% CI: 36.48%-99.12%), and 96.30%(95% CI: 80.20%-99.99%), respectively. The subgroup analysis revealed that FNB could obtain sufficient specimens and high diagnostic yields in both gallbladder mass < 20.5 mm group and ≥20.5 mm group. One patient experienced mild abdominal pain after the procedure and recovered within one day. Conclusions: EUS-FNB is a reasonable diagnostic tool for the pretreatment diagnosis of patients with gallbladder masses, especially for patients who may miss the opportunity of surgery and need sufficient specimens to identify the pathological type so as to determine chemotherapy regimens. Further largescale studies are needed to confirm our conclusion.

Is endoscopic ultrasound a promising technique in the diagnosis and treatment of liver diseases?

Percutaneous ultrasound has been a longstanding method in the diagnostics and interventional procedures of liver diseases.In some countries,its use is restricted to radiologists,limiting access for other clinicians,such as gastroenterologists.Endoscopic ultrasound,as a novel technique,plays a crucial role in diagnosis and treatment of digestive diseases.However,its use is sometimes recommended for conditions where no clear advantage over percutaneous ultrasound exists,leaving the impression that clinicians sometimes resort to an endoscopic approach due to the unavailability of percutaneous options.

Strategic insights into the cultivation of pancreatic cancer organoids from endoscopic ultrasonography-guided biopsy tissue

BACKGROUND The frequent suboptimal efficacy of endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB)to culture pancreatic cancer(PC)organoids(PCOs)poses a major challenge in the advancement of personalized medicine for advanced PC.AIM To explore how to obtain appropriate puncture tissues from EUS-FNB and optimize the strategy for efficiently constructing PCOs,providing an efficient tool for the advancement of personalized medicine.METHODS Patients who underwent EUS-FNB for the diagnosis of PC tissue were prospectively enrolled.We refined the endoscopic biopsy procedures and organoid cultivation techniques.All tissue specimens verified by on-site pathological assessment were cultured in a semi-suspended medium in a microfluidic environment.We assessed differences in PCOs cultured beyond and below five generations examining patient demographics,specimen and organoid attributes,and the sensitivity of organoids to a panel of clinical drugs through cell viability assays.RESULTS In this study,16 patients with PC were recruited,one sample was excluded because onsite cytopathology showed no tumor cells.Successful organoid generation occurred in 93.3%(14 of 15)of the EUS-FNB specimens,with 60%(9 of 15)sustaining over five generations.Among these patients,those with a history of diabetes,familial cancer,or larger tumors exhibited enhanced PCO expandability.The key factors influencing longterm PCOs expansion included initial needle sample quality(P=0.005),rapid initiation of organoid culture postisolation(P≤0.001),and high organoid activity(P=0.031).Drug sensitivity analysis revealed a partial response in two patients following therapeutic intervention and surgery and stable disease in four patients,indicating a moderate correlation between organoid response and clinical outcomes.CONCLUSION Optimal initial needle sampling,rapid and precise biopsy sample processing,process isolated samples as soon as possible,and sufficient cellular material are crucial for successful cultivating PCOs.High organoid activity is an important factor in maintaining their long-term expansion,which is essential for shortening the time of drug sensitivity analysis and is the basis of PC research.

Comprehensive review on endoscopic ultrasound-guided tissue acquisition techniques for solid pancreatic tumor

Pancreatic ductal adenocarcinoma is speculated to become the second leading cause of cancer-related mortality by 2030,a high mortality rate considering the number of cases.Surgery and chemotherapy are the main treatment options,but they are burdensome for patients.A clear histological diagnosis is needed to determine a treatment plan,and endoscopic ultrasound(EUS)-guided tissue acquisition(TA)is a suitable technique that does not worsen the cancer-specific prognosis even for lesions at risk of needle tract seeding.With the development of personalized medicine and precision treatment,there has been an increasing demand to increase cell counts and collect specimens while preserving tissue structure,leading to the development of the fine-needle biopsy(FNB)needle.EUS-FNB is rapidly replacing EUS-guided fine-needle aspiration(FNA)as the procedure of choice for EUS-TA of pancreatic cancer.However,EUS-FNA is sometimes necessary where the FNB needle cannot penetrate small hard lesions,so it is important clinicians are familiar with both.Given these recent developments,we present an up-to-date review of the role of EUS-TA in pancreatic cancer.Particularly,technical aspects,such as needle caliber,negative pressure,and puncture methods,for obtaining an adequate specimen in EUS-TA are discussed.

Septic shock due to Granulicatella adiacens after endoscopic ultrasound-guided biopsy of a splenic mass:A case report

BACKGROUND Endoscopic ultrasound-guided fine needle aspiration or biopsy(EUS-FNA or FNB)has become a popular method for diagnosing various lesions of the gastrointestinal tract and surrounding tissue due to the accuracy and safety.To the best of our knowledge,no case report of severe infection after EUS-FNB of a solid lesion in the spleen has been described.Herein,we report a rare case of septic shock after EUS-FNB of a splenic mass.CASE SUMMARY A 45-year-old male patient presented to the outpatient clinic due to an incidentally detected splenic mass.A definitive diagnosis could not be established based on the abdominal magnetic resonance imaging.EUS of the spleen showed a 6 cm-sized,relatively well-demarcated,heterogeneous mass,and EUS-FNB with a 22G needle was performed.Ten days after the procedure patient developed septic shock and a splenic abscess was identified.Blood culture revealed growth of Granulicatella adiacens.After the treatment with antibiotics the patient underwent surgical resection,and the pathological examination showed diffuse large B-cell lymphoma.The patient received chemotherapy and he is in complete remission.CONCLUSION Infection of a splenic mass after EUS-FNB is a rare complication and prophylactic antibiotics might be considered.

Endoscopic ultrasound-guided fine-needle aspiration biopsy-Recent topics and technical tips

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) is a useful procedure that enables reliable pathological diagnoses of pancreatobiliary diseases, subepithelial lesions, and swollen lymph nodes. In recent years, a pathological diagnosis based on EUS-FNA has made it possible to provide accurate treatment methods not only in these fields, but also in respiratory organs and otorhinolaryngology. This review discusses the latest topics pertaining to EUS-FNA as well as procedural tips.

Endoscopic ultrasound-guided through-the-needle microforceps biopsy and needle-based confocal laser-endomicroscopy increase detection of potentially malignant pancreatic cystic lesions:A single-center study

BACKGROUND Currently,there is insufficient data about the accuracy in the diagnosing of pancreatic cystic lesions(PCLs),especially with novel endoscopic techniques such as with direct intracystic micro-forceps biopsy(mFB)and needle-based confocal laser-endomicroscopy(nCLE).AIM To compare the accuracy of endoscopic ultrasound(EUS)and associated techniques for the detection of potentially malignant PCLs:EUS-guided fine needle aspiration(EUS-FNA),contrast-enhanced EUS(CE-EUS),EUS-guided fiberoptic probe cystoscopy(cystoscopy),mFB,and nCLE.METHODS This was a single-center,retrospective study.We identified patients who had undergone EUS,with or without additional diagnostic techniques,and had been diagnosed with PCLs.We determined agreement among malignancy after 24-mo follow-up findings with detection of potentially malignant PCLs via the EUSguided techniques and/or EUS-guided biopsy when available(EUS malignancy detection).RESULTS A total of 129 patients were included, with EUS performed alone in 47/129. In 82/129 patients,EUS procedures were performed with additional EUS-FNA (21/82), CE-EUS (20/82), cystoscopy(27/82), mFB (36/82), nCLE (44/82). Agreement between EUS malignancy detection and the 24-mo follow-up findings was higher when associated with additional diagnostic techniques thanEUS alone [62/82 (75.6%) vs 8/47 (17%);OR 4.35, 95%CI: 2.70-7.37;P < 0.001]. The highestmalignancy detection accuracy was reached when nCLE and direct intracystic mFB were bothperformed, with a sensitivity, specificity, positive predictive value, negative predictive value andobserved agreement of 100%, 89.4%, 77.8%, 100% and 92.3%, respectively (P < 0.001 comparedwith EUS-alone).CONCLUSIONThe combined use of EUS-guided mFB and nCLE improves detection of potentially malignantPCLs compared with EUS-alone, EUS-FNA, CE-EUS or cystoscopy.

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.

Hemobilia and other complications caused by percutaneous ultrasound-guided liver biopsy

Hemobilia accounts for approximately 3%of all major percutaneous liver biopsy complications,and rarely results from arterioportal fistula.We report a patient who suffered from four complications over 11 d after ultrasound-guided percutaneous liver biopsy:hemobilia,acute pancreatitis,acute cholecystitis,and multiple stomach ulcers.Digital subtraction angiography was done after consultation with doctors,and showed obvious arteriovenous fistula of the right liver.The hepatic artery was selected and embolized by spring orbs.The active bleeding was stopped after embolization of the hepatic artery.The patient was discharged home on day 12 after embolization and remained well.

Overlooked risk for needle tract seeding following endoscopic ultrasound-guided minimally invasive tissue acquisition

Endoscopic ultrasound-guided minimally invasive tissue acquisition can be performed by two approaches as follows: Endoscopic ultrasound-guided fineneedle aspiration(EUS-FNA) and endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB). These have been evolved into leading approaches and widely used for the histological diagnosis of tumors in the gastrointestinal tract and adjacent organs. However, the role of EUS-FNA and EUS-FNB in disease diagnosis and evaluation remains controversial. Although the incidence of surgery-associated complications remains low, the consequences of needle tract seeding can be serious or even life-threatening. Recently, increasing case reports of needle tract seeding are emerging, especially caused by EUS-FNA. This complication needs serious consideration. In the present work, we integrated these case reports and the related literature, and summarized the relevant cases and technical characteristics of needle tract seeding caused by EUS-FNA and EUSFNB. Collectively, our findings provided valuable insights into the prevention and reduction of such serious complication.

Endoscopic ultrasound guided liver biopsy for parenchymal liver disease

Liver biopsy plays an essential role in the diagnosis, evaluation and management of a vast proportion of liver diseases. Conventionally, percutaneous and transjugular approaches have been used to obtain liver biopsies. Endoscopic ultrasound guided liver biopsy(EUS-LB) has emerged as a safe and effective alternate in the past two decades. EUS-LB carries a role in evaluation of both benign and malignant diseases of the liver. It can offer higher resolution imaging of the liver and can detect smaller lesions than computed tomography scan of the abdomen or ultrasound scans with the option for doppler assistance to reduce complications. Current evidence demonstrates the superiority of EUS-LB for a targeted approach of focal lesion and there is also evidence of less sampling variability in heterogeneous parenchymal pathologies. These advantages combined with an improved safety profile had led to the rapid progress in the development of new techniques, equipment and procedures for EUS-LB. We provide a comprehensive review of EUS-LB for parenchymal liver disease.

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.

Endoscopic retrograde cholangiopancreatography and liver biopsy in the evaluation of elevated liver function tests after liver transplantation

BACKGROUND Abnormal liver function tests(LFTs)in post-liver transplant(LT)patients pose a challenge in the timing and selection of diagnostic modalities.There are little data regarding the accuracy of endoscopic retrograde cholangiopancreatography(ERCP)and liver biopsy(LB)in diagnosing post-transplant complications.AIM To evaluate the diagnostic performance of ERCP and LB in patients with nonvascular post-LT complications.METHODS This single-center retrospective study evaluated patients undergoing both ERCP and LB for evaluation of elevated LFTs within 6 mo of LT from 2000 to 2017.Diagnostic operating characteristics including accuracy,sensitivity and specificity for various diagnoses were calculated for ERCP and LB.The R factor(ratio of alkaline phosphatase to alanine aminotransferase)was also calculated for each patient.RESULTS Of the 1284 patients who underwent LT,91 patients(74.7%males,mean age of 51)were analyzed.Anastomotic strictures(AS,24.2%),acute cellular rejection(ACR,11%)and concurrent AS/ACR(14.3%)were the most common diagnoses.ERCP carried an accuracy of 79.1%(95%CI:69.3-86.9),LB had an accuracy of 93.4%(95%CI:86.2-97.5),and the combination of the two had an accuracy of 100%(95%CI:96-100).There was no difference between patients with AS and ACR in mean R factor(AS:1.9 vs ACR:1.1,P=0.24).Adverse events did not differ between the two tests(ERCP:3.1%vs LB:1.1%,P=0.31).CONCLUSION In patients with abnormal LFTs after LT without vascular complications,the combination of LB and ERCP carries low risk and improves diagnostic accuracy over either test alone.

Peritoneal dissemination of pancreatic cancer caused by endoscopic ultrasound-guided fine needle aspiration:A case report and literature review

BACKGROUND Endoscopic ultrasound-guided fine needle aspiration(EUS-FNA)is a biopsy technique widely used to diagnose pancreatic tumors because of its high sensitivity and specificity.Although needle-tract seeding caused by EUS-FNA has been recently reported,dissemination of pancreatic cancer cells is generally considered to be a rare complication that does not affect patient prognosis.However,the frequency of dissemination and needle-tract seeding appears to have been underestimated.We present a case of peritoneal dissemination of pancreatic cancer due to preoperative EUS-FNA.CASE SUMMARY An 81-year-old man was referred to the Department of Surgery of our hospital in Japan owing to the detection of a pancreatic mass on computed tomography during medical screening.Trans-gastric EUS-FNA revealed that the mass was an adenocarcinoma;hence laparoscopic distal pancreatectomy with lymphadenectomy was performed.No intraoperative peritoneal dissemination and liver metastasis were visually detected,and pelvic lavage cytology was negative for carcinoma cells.The postoperative surgical specimen was negative for carcinoma cells at the dissected margin and the cut end margin;however,pathological findings revealed adenocarcinoma cells on the peritoneal surface proximal to the needle puncture site,and the cells were suspected to be disseminated via EUSFNA.Hence,the patient received adjuvant therapy with S-1(tegafur,gimeracil,and oteracil potassium);however,computed tomography performed 5 mo after surgery revealed liver metastasis and cancerous peritonitis.The patient received palliative therapy and died 8 mo after the operation.CONCLUSION The indications of EUS-FNA should be carefully considered to avoid iatrogenic dissemination,especially for cancers in the pancreatic body or tail.

Endoscopic ultrasound guided liver biopsy: Recent evidence

Liver biopsy(LB)is an essential tool in diagnosing,evaluating and managing various diseases of the liver.As such,histopathological results are critical as they establish or aid in diagnosis,provide information on prognosis,and guide the appropriate selection of medical therapy for patients.Indications for LB include evaluation of persistent elevation of liver chemistries of unclear etiology,diagnosis of chronic liver diseases such as Wilson's disease,autoimmune hepatitis,small duct primary sclerosing cholangitis,work up of fever of unknown origin,amyloidosis and more.Traditionally,methods of acquiring liver tissue have included percutaneous LB(PCLB),transjugular LB(TJLB)or biopsy taken surgically via laparotomy or laparoscopy.However,traditional methods of LB may be inferior to newer methods.Additionally,PCLB and TJLB carry higher risks of adverse events and complications.More recently,endoscopic ultrasound guided LB(EUS-LB)has evolved as an alternative method of tissue sampling that has proven to be safe and effective,with limited adverse events.Compared to PC and TJ routes,EUS-LB may also have a greater diagnostic yield of tissue,be superior for a targeted approach of focal lesions,provide higher quality images and allow for greater patient comfort.These advantages have contributed to the increased use of EUS-LB as a technique for obtaining liver tissue.Herein,we provide a review of the recent evidence of EUS-LB for liver disease.

Endoscopic ultrasound-through-the-needle biopsy in pancreatic cystic lesions: A large single center experience

BACKGROUND Establishing a diagnosis of pancreatic cystic lesions(PCLs)preoperatively still remains challenging.Recently,endoscopic ultrasound(EUS)-through-the-needle biopsy(EUS-TTNB)using microforceps in PCLs has been made available.AIM To assess the efficacy and safety of EUS-TTNB in the diagnosis of PCLs.METHODS We retrospectively collected data of patients with PCLs who underwent both EUS-fine-needle aspiration(FNA)for cytology and EUS-TTNB at our institution since 2016.EUS-FNA for cytology was followed by EUS-TTNB in the same session.Evaluation of the cyst location,primary diagnosis,adverse events,and comparison between the cytologic fluid analyses and histopathology was performed.Technical success of EUS-TTNB was defined as visible tissue present after biopsy.Clinical success was defined as the presence of a specimen adequate to make a histologic or cytologic diagnosis.RESULTS A total of 56 patients(mean age 66.9±11.7,53.6%females)with PCLs were enrolled over the study period.The mean cyst size was 28.8 mm(12-85 mm).The EUS-TTNB procedure was technically successful in all patients(100%).The clinical success rate using EUS-TTNB was much higher than standard EUS-FNA,respectively 80.4%(45/56)vs 25%(14/56).Adverse events occurred in 2 patients(3.6%)who developed mild pancreatitis that resolved with medical therapy.Using TTNB specimens,23 of 32 cases(71.9%)with intraductal papillary mucinous neoplasm were further differentiated into gastric type(19 patients)and pancreaticobiliary type(4 patients)based on immunochemical staining.CONCLUSION EUS-TTNB for PCLs was technically feasible and had a favorable safety profile.Furthermore,the diagnostic yield for PCLs was much higher with EUS-TTNB than standard EUS-FNA cytology and fluid carcinoembryonic antigen.EUSTTNB should be considered as an adjunct to EUS-FNA and cytologic analysis in the diagnosis and management of PCLs.