Diagnostic performance and safety of endoscopic ultrasound-guided fine-needle aspiration/biopsy for gallbladder lesions.

OBJECTIVES: Endoscopic ultrasound-guided fine-needle aspiration and fine-needle biopsy (EUS-FNA/FNB) is not fully established as a pathological sampling tool for gallbladder lesions due to limited evidence. We therefore aimed to clarify the effectiveness and safety of this procedure in a large-population cohort. METHODS: This study retrospectively evaluated the diagnostic yield of EUS-FNA/FNB for accurately differentiating between benign and malignant gallbladder lesions. Puncture targets included the gallbladder mass, lymph node, and liver mass. Adverse events and factors associated with diagnostic accuracy were analyzed as well. RESULTS: In 187 patients with gallbladder lesions undergoing EUS-FNA/FNB, 18 benign lesions and 169 malignant lesions were identified. Overall sampling adequacy was 98% (184/187). The diagnostic accuracy of EUS-FNA/FNB was 97% (182/187), sensitivity was 97% (164/169), and specificity was 100% (18/18). A single postprocedural complication (minor bleeding) was recorded in one patient. In the 169 cases of malignancy, 203 sites were punctured for pathological sampling of the primary mass (n = 94), lymph node (n = 79), and metastatic liver mass (n = 30). No significant difference was found for diagnostic accuracy among the puncture sites (P = 0.70). In cases having specimens obtained from the primary mass, the accuracy of those targeting liver invasion sites was significantly higher than that of other sites (98% vs. 83%, P < 0.01). CONCLUSION: EUS-FNA/FNB demonstrated clinical usefulness and safety for the pathological diagnosis of gallbladder lesions, with high diagnostic yield and a low incidence of adverse events. Targeting the site of liver infiltration may improve the diagnostic rate of EUS-FNA/FNB in the primary mass.

Diagnostic value of SpyGlass for pancreatic cystic lesions: comparison of EUS-guided fine-needle aspiration and EUS-guided fine-needle aspiration combined with SpyGlass.

BACKGROUND AND AIMS: No study has evaluated the diagnostic value of SpyGlass by comparing SpyGlass results and non-SpyGlass results. In this retrospective study, we aimed to compare the diagnostic value of EUS-guided fine-needle aspiration (EUS-FNA) and EUS-FNA combined with SpyGlass to evaluate whether SpyGlass is valuable for increasing the diagnostic yield of EUS-FNA. METHODS: From April 2015 to April 2020, 251 patients suspected of having pancreatic cystic lesions (PCLs) by imaging techniques who then underwent EUS-FNA were retrospectively enrolled. Only 98 patients who underwent surgical resection with a pathological diagnosis of pancreatic cystic lesion (PCL) were studied. The diagnostic performance outcomes were compared between the EUS-FNA group (EUS-FNA alone, n = 40) and the SpyGlass group (EUS-FNA combined with SpyGlass, n = 58) to assess the value of SpyGlass in diagnosing PCLs. RESULTS: There were 71 females and 27 males with an overall mean age of 47.6 years. The median diameter of the PCLs was 42.2 mm (range, 11.4-100.0 mm). Approximately 37 cysts were localized in the head/neck of the pancreas, while 61 in the body/tail. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of the EUS-FNA group were 96.4% (27/28), 83.3% (10/12), 93.1% (27/29), 90.9% (10/11) and 92.5% (37/40), while those in the SpyGlass group were 100% (54/54), 75% (3/4), 98.2% (54/55), 100% (3/3) and 98.3% (57/58), respectively. The diagnostic accuracy rate in the SpyGlass group was higher than that in the EUS-FNA group; however, no significant difference was found between the two groups (P = 0.368). The diagnostic accuracy of evaluating specific cyst types in the EUS-FNA group was 85% (34/40), similar to that in the SpyGlass group (85.0% vs 84.5%, P = 0.944). CONCLUSION: SpyGlass seems less valuable for the diagnosis of PCLs when EUS and EUS-FNA have been performed by experienced endoscopists.

Factors influencing diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in pancreatic and biliary tumors.

BACKGROUND AND AIM: Diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is influenced by several factors, primarily operator expertise. Formal training in EUS-FNA, as suggested by the European Society of Gastrointestinal Endoscopy and the American Society for Gastrointestinal Endoscopy guidelines, is not always available and is often expensive and time-consuming. In this study we evaluate factors influencing the diagnostic accuracy of pancreatic EUS-FNA. METHODS: In a retrospective study, 557 consecutive EUS-FNAs were evaluated. Several variables relating to the procedures were considered to calculate the EUS-FNA performance over eight years. RESULTS: A total of 308 out of 557 EUS-FNAs were selected. Overall sensitivity of EUS-FNA was 66% (95% CI: 60.8-71.8), specificity 100%, and diagnostic accuracy 69% (95% CI: 64.0-74.4). An increase in diagnostic accuracy was observed to >90% using a new fine-needle biopsy (FNB) needle and in the case of simultaneous sampling of primary and metastatic lesions. Diagnostic accuracy >80% was observed after 250 procedures, in the absence of rapid on-site cytopathological examination (ROSE). Multivariate logistic regression analysis confirmed that the FNB needle, operator skill, and double EUS-FNA sampling are associated with high diagnostic accuracy. CONCLUSIONS: The learning curve for EUS-FNA may be longer and a considerable number of procedures are needed to achieve high diagnostic accuracy in the absence of ROSE. However, the use of FNB needles and the simultaneous sampling of primary and metastatic lesions can rapidly improve the diagnostic accuracy of the procedure.

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.

Endoscopic ultrasound-guided tissue acquisition.

Endoscopic ultrasound (EUS) is an indispensable tool for tissue acquisition in patients with gastrointestinal tumors. While fine-needle aspiration (FNA) has been routinely carried out for establishing tissue diagnosis, the emerging concept of tailoring chemotherapeutic agents based on molecular markers has increased the demand for core tissue procurement by means of EUS-guided fine-needle biopsy (EUS-FNB). In addition, FNB may offset the limitations of FNA wherein the diagnostic sensitivity is incumbent on the availability of an onsite cytopathologist. Given the increasing number of procedures being done, developing a unit-specific algorithmic approach for needle selection is important to improve the procedural efficiency and utilization of resources. Finally, the best outcomes can be attained only by practicing evidence-based techniques, procuring adequate quantity of sample for ancillary studies and processing the specimens appropriately.

Endoscopic ultrasound-guided tissue acquisition for comprehensive genomic profiling.

Advances in next-generation sequencing have made comprehensive genomic profiling (CGP) using tumor tissue specimens and liquid biopsy using blood samples feasible in routine clinical practice. In the context of pancreaticobiliary cancer, it is necessary to consider CGP in formulating individualized treatment strategies. Performing CGP with tumor tissue specimens requires a sufficient number of high-quality samples. EUS-guided tissue acquisition (EUS-TA) is expected to play a significant role in this regard, and endosonographers need to address this role. Here, we review the current status of EUS-TA for CGP focusing on pancreatic cancer and biliary tract cancer.

EUS-FNA versus EUS-FNB in Pancreatic Solid Lesions ≤ 15 mm.

A small tumor size may impact the diagnostic performance of endoscopic ultrasound-guided tissue acquisition (EUS-TA) for diagnosing solid pancreatic lesions (SPLs). We aimed to compare the diagnostic yield of EUS-guided fine-needle aspiration (FNA) and biopsy (FNB) in SPLs with a diameter ≤ 15 mm. Consecutive patients who underwent EUS-TA for SPLs ≤ 15 mm between January 2015 and December 2022 in a tertiary referral center were retrospectively evaluated. The primary endpoint was diagnostic accuracy. The final diagnosis was based on surgical pathology or disease evolution after a minimum follow-up of 6 months. Inadequate samples were all considered false negatives for the study. Secondary outcomes included sample adequacy, factors impacting accuracy, and safety. We included 368 patients (52.4% male; mean age: 60.2 years) who underwent FNA in 72 cases and FNB in 296. The mean size of SPLs was 11.9 ± 2.6 mm. More than three passes were performed in 5.7% and 61.5% of patients in the FNB and FNA groups, respectively (p < 0.0001). FNB outperformed FNA in terms of diagnostic accuracy (89.8% vs. 79.1%, p = 0.013) and sample adequacy (95.9% vs. 86.1%, p < 0.001). On multivariate analysis, using FNA (OR: 2.10, 95% CI: 1.07-4.48) and a final diagnosis (OR: 3.56, 95% CI: 1.82-6.94) of benign conditions negatively impacted accuracy. Overall, the adverse event rate was 0.8%, including one pancreatitis in the FNA group and one pancreatitis and one bleeding in the FNB group, all mild and conservatively managed. EUS-TA for SPLs ≤ 15 mm has a high diagnostic yield and safety. This study suggests the superiority of FNB over FNA, with better performance even with fewer passes performed.

Current status and issues in genomic analysis using EUS-FNA/FNB specimens in hepatobiliary-pancreatic cancers.

Comprehensive genomic profiling based on next-generation sequencing has recently been used to provide precision medicine for various advanced cancers. Endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) and EUS-guided fine-needle biopsy (EUS-FNB) play essential roles in the diagnosis of abdominal masses, mainly pancreatic cancers. In recent years, CGP analysis using EUS-FNA/FNB specimens for hepatobiliary-pancreatic cancers has increased; however, the success rate of CGP analysis is not clinically satisfactory, and many issues need to be resolved to improve the success rate of CGP analysis. In this article, we review the transition from EUS-FNA to FNB, compare each test, and discuss the current status and issues in genomic analysis of hepatobiliary-pancreatic cancers using EUS-FNA/FNB specimens.

Diagnosis by Endoscopic Ultrasonography-Guided Sampling through the Lower Gastrointestinal Tract.

Endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) is very safe and has a high diagnostic rate for upper gastrointestinal lesions, especially pancreatic lesions, but its application in the lower gastrointestinal tract has rarely been reported. Due to the tortuous course of the colorectum, with the sigmoid colon particularly prone to perforation, most endoscopists are reluctant to perform lateral-sector endoscopic ultrasound scanning without a water-bag protection for the puncture. The ultrasonic endoscopy and flexible puncture needle techniques recently introduced into clinical practice have made ultrasound-guided puncture safer and more convenient. In addition, endoscopists have carefully tested various protective measures to improve the safety of the lower gastrointestinal puncture, substantially increasing its clinical feasibility. In this article, we review the iterations of endoscopic ultrasound equipment introduced in recent years and the many ingenious ideas proposed by endoscopists regarding lower gastrointestinal puncture.

Usefulness of the automated multiband imaging system for EUS-FNA biopsy specimen evaluation in patients with upper gastrointestinal subepithelial lesions.

Background and Objectives: Sample isolation processing by stereomicroscopy (SIPS) was recently introduced as an alternative to rapid on-site cytologic evaluation and showed high accuracy for use in pathologic diagnoses. SIPS is a useful, but slightly complicated procedure; therefore, a new, more straightforward method for the objective estimation of the core tissue amount required during the sampling is desirable. We evaluated the usefulness of the automated multiband imaging system (AMUS) for calculating whitish core amounts in EUS-FNA biopsy (EUS-FNAB) samples from patients with subepithelial lesions (SELs). Methods: Four EUS-FNAB specimens per patient were obtained from 20 patients with upper gastrointestinal SELs. The correlation between the whitish core amount calculated by AMUS, length of the manually measured whitish cores (stereomicroscopically visible white core [SVWC]), and sample suitability for pathologic evaluation were analyzed. Results: We identified 13 patients with gastrointestinal stromal tumors, five with leiomyomas, one with a schwannoma, and one with an ectopic pancreas. The histological diagnostic accuracy was 100%, median SVWC length was 9 mm, and median whitish core area, calculated using AMUS, was 10 mm2. SVWC length correlated with whitish core amount (ρ = 0.81, P < 0.01) and adequacy score (ρ = 0.54, P < 0.01). Whitish core amount correlated with adequacy score (ρ = 0.54, P < 0.01). The area under the receiver-operating characteristic curve calculated for whitish core amount with respect to the histological diagnosis was 0.83 (P < 0.01; cutoff ≥4 mm2, sensitivity 98.4%). Conclusions: AMUS, a simple on-site verification instrument, is an alternative to SIPS for determining the appropriate SEL tissue sampling quantity with high diagnostic accuracy.

A case of early gastric cancer resembling a subepithelial lesion diagnosed by endoscopic ultrasound-guided fine needle aspiration.

We present a case of early gastric cancer resembling a subepithelial lesion (GCSEL) derived from the submucosal ectopic gastric glands (SEGGs), diagnosed using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). A 55-year-old woman was referred to our hospital for the investigation of a subepithelial lesion (SEL). Contrast computed tomography and esophagogastroduodenoscopy revealed two SELs in the greater curvature of the fundus and the posterior wall of the upper body of the stomach. EUS revealed a hypoechoic lesion in the submucosa and suggested partial invasion into the muscularis propria of the greater curvature of the fundus, and an anechoic lesion in the submucosa of the posterior wall of the upper body. The different diagnosis for the SEL in the fundus was GCSEL, neuroendocrine tumor, malignant lymphoma, and gastric adenocarcinoma of fundic gland type. EUS-FNA findings suggested adenocarcinoma. The patient underwent a laparoscopic proximal gastrectomy. Pathological findings confirmed a differentiated tubular adenocarcinoma derived from the SEGG, which partially invaded into the submucosa of the surrounding gastric wall without lymphovascular invasion or lymph node metastasis. The patient has been recurrence-free after 10 months of follow-up. EUS should be performed for SELs followed by EUS-FNA for lesions, such as GCSEL, that require early intervention.

The Utility of Endoscopic-Ultrasonography-Guided Tissue Acquisition for Solid Pancreatic Lesions.

Endoscopic-ultrasonography-guided tissue acquisition (EUS-TA) has been widely performed for the definitive diagnosis of solid pancreatic lesions (SPLs). As the puncture needles, puncture techniques, and sample processing methods have improved, EUS-TA has shown higher diagnostic yields and safety. Recently, several therapeutic target genomic biomarkers have been clarified in pancreatic ductal carcinoma (PDAC). Although only a small proportion of patients with PDAC can benefit from precision medicine based on gene mutations at present, precision medicine will also be further developed for SPLs as more therapeutic target genomic biomarkers are identified. Advances in next-generation sequencing (NGS) techniques enable the examination of multiple genetic mutations in limited tissue samples. EUS-TA is also useful for NGS and will play a more important role in determining treatment strategies. In this review, we describe the utility of EUS-TA for SPLs.

A randomized noninferiority trial comparing the diagnostic yield of the 25G ProCore needle to the standard 25G needle in suspicious pancreatic lesions.

BACKGROUND AND OBJECTIVES: The aim of the study was to perform the first randomized trial comparing the diagnostic yield, bloodiness, and cellularity of the 25G standard needle (25S) and the 25G ProCore™ needle (25P). MATERIALS AND METHODS: All patients referred to the tertiary care referral center for EUS guided fine-needle aspiration (EUS-FNA) of suspicious solid pancreatic lesions were eligible. EUS-FNA was performed in each lesion with both 25S and 25P needles (the choice of the first needle was randomized), using a multipass sampling pattern, without stylet or suction. Rapid on-site evaluation was used when possible. Pap-stained slides were read by a single experienced cytopathologist, blinded to the needle type. RESULTS: One hundred and forty-three patients were recruited. Samples were positive for cancer in 122/143 (85.3%) with the 25S needle versus 126/143 (88.1%) with the 25P needle, negative in 17/143 (11.9%) with the 25S needle versus 13/143 (9.1%) with the 25P needle, and suspicious in 4/143 (2.8%) with each needle. There was no difference in any outcome based on the type of the first needle. No carryover effect was detected (P = 0.214; NS). Cumulative logistic regression analyses showed no associations between the type of needle and diagnostic yield for cancer, cellularity, or bloodiness. The difference in the yield for cancer was 2.9% (-4.2; 10.1%); with the confidence interval upper within the predetermined noninferiority margin of 15%. CONCLUSION: The 25S needle is noninferior to the 25P needle for diagnosing cancer in suspicious pancreatic lesions.

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

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

The Role of Endoscopic Ultrasound in the Diagnosis of Gallbladder Lesions.

Gallbladder (GB) diseases represent various lesions including gallstones, cholesterol polyps, adenomyomatosis, and GB carcinoma. This review aims to summarize the role of endoscopic ultrasound (EUS) in the diagnosis of GB lesions. EUS provides high-resolution images that can improve the diagnosis of GB polypoid lesions, GB wall thickness, and GB carcinoma staging. Contrast-enhancing agents may be useful for the differential diagnosis of GB lesions, but the evidence of their effectiveness is still limited. Thus, further studies are required in this area to establish its usefulness. EUS combined with fine-needle aspiration has played an increasing role in providing a histological diagnosis of GB tumors in addition to GB wall thickness.

Simplified Submucosal Tunneling Biopsy Using Clip-With-Line Traction and Closure for Gastric Subepithelial Lesion.

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has emerged as a standard and convenient method for the sampling of subepithelial lesions (SELs). Immunohistological analysis is required to definitively distinguish mesenchymal tumors; however, EUS-FNA provides insufficient material to achieve this, especially for small SELs < 2 cm. We therefore previously reported a novel submucosal tunneling biopsy (STB) technique that utilizes endoscopic submucosal dissection (ESD) for sampling SELs. However, unresolved advanced technical issues have hindered its widespread application. Currently, a counter-traction technique is used to facilitate ESD. We here describe a technically simplified STB technique using clip-with-line traction for gastric SELs.

Mesenchymal neoplasms of the tubular gut and adjacent structures: experience with EUS-guided fine-needle aspiration cytopathology.

INTRODUCTION: Unlike epithelial malignancies, mesenchymal neoplasms arising within the tubular gut are less often encountered in endoscopic ultrasound-guided (EUS) fine-needle aspiration biopsies (FNABs). Nonetheless, preoperative diagnosis of such neoplasms has important therapeutic and prognostic value. We report our experience with this category of neoplasms from the past decade. MATERIALS AND METHODS: We performed a 10-year retrospective search at our respective institutions to identify EUS-guided FNAB cases of mesenchymal neoplasms arising from the tubular gut wall and closely adjacent structures. Cytopathologic diagnoses were compared to corresponding surgical pathology (SP) when available. Cases with either no confirmatory cell block (CB) immunohistochemical (IHC) staining, or no SP were excluded. RESULTS: Two-hundred eighty-two cases (M:F = 1:1; age range: 25-94 years, mean age = 60 years) of EUS-guided FNAB from the tubular gut met our criteria. Onsite adequacy was performed on nearly all cases. Case numbers: 209 gastrointestinal stromal tumors (GIST), 58 smooth muscle neoplasms, and 15 miscellaneous neoplasms. Of these, 188 (67%) had SP follow-up. We found that 258 (91%) aspirates had a correct specific diagnosis, 3 (1%) were nondiagnostic, 18 (6%) had indeterminate diagnoses, and 3 (1%) had incorrect diagnoses (2 leiomyosarcomas mistaken as leiomyoma, and 1 fibrosclerotic lesion mistaken as inflammatory pseudotumor). Of 94 cases with no SP, all had a specific cytologic diagnosis based on confirmatory IHC staining from the CB including 61 GISTs, 29 smooth muscle neoplasms, and 4 miscellaneous tumors. CONCLUSION: This study endorses the clinical utility of EUS-guided FNAB in the diagnosis of tubular gut mesenchymal neoplasms. A definitive and accurate diagnosis is possible in over 90% of cases, chiefly when cytomorphology is coupled with optimal cellularity and IHC from a concurrent CB. EUS-guided FNAB diagnosis of mesenchymal tubular gut neoplasms may play an important role in determining neoadjuvant therapy as targeted therapy evolves.

The Diagnosis of Autoimmune Pancreatitis Using Endoscopic Ultrasonography.

Autoimmune pancreatitis (AIP) is characterized by enlargement of the pancreas and irregular narrowing of the main pancreatic duct. It is often associated with IgG4-related sclerosing cholangitis (IgG4-SC), in which the bile duct narrows. Although characteristic irregular narrowing of the pancreatic duct caused by endoscopic retrograde cholangiopancreatography is noted in AIP, it is difficult to differentiate between localized AIP and pancreatic carcinoma based on imaging of the pancreatic duct. While stenosis of the bile duct in IgG4-SC is characterized by longer-length stenosis than in cholangiocarcinoma, differentiation based on bile duct imaging alone is challenging. Endoscopic ultrasound (EUS) can characterize hypoechoic enlargement of the pancreas or bile duct wall thickening in AIP and IgG4-SC, and diagnosis using elastography and contrast-enhanced EUS are being evaluated. The utility of EUS-guided fine needle aspiration for the histological diagnosis of AIP has been reported and is expected to improve diagnostic performance for AIP. Findings in the bile duct wall from endoscopic retrograde cholangiopancreatography followed by intraductal ultrasonography are useful in differentiating IgG4-SC from cholangiocarcinoma. Diagnoses based on endoscopic ultrasonography play a central role in the diagnosis of AIP.

Multidisciplinary diagnostic and therapeutic approaches to pancreatic cystic lesions.

Pancreatic cystic lesions are commonly encountered today with the routine use of cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). The majority of patients discovered to have a pancreatic cyst are completely asymptomatic; yet the presence of such a finding instills fear in the minds of both patient and physician, as the concern for malignant transformation to pancreatic cancer is great despite the relatively low overall likelihood of cyst progression. Not all cysts in the pancreas represent pancreatic cystic neoplasms (PCNs), and not all PCNs have significant malignant potential. Mucinous PCNs are the most concerning, as these lesions have the greatest potential for cancerous transformation to adenocarcinoma. Within the group of mucinous PCNs, intraductal papillary mucinous neoplasms (IPMNs) involving the main pancreatic duct are the most worrisome, and surgical resection should be pursued if the patient has appropriate operative risks. IPMN lesions involving the branch ducts, and mucinous cystadenomas, have a lower likelihood for malignancy, and they may be closely followed for the development of any worrisome or high-risk features. Surveillance of known PCNs is performed with a combination of CT, MRI and endoscopic ultrasound (EUS). EUS-guided fine-needle aspiration (EUS-FNA) may be used to assess cyst fluid cytology, and also to detect cyst fluid amylase level, carcinoembryonic antigen level, and DNA molecular analysis in certain cases. The presence or absence of specific cyst morphological features, as well as the cyst fluid analysis, is what enables the physician to guide the patient towards continued surveillance, versus the pursuit of surgical resection.