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The role of endoscopy in the diagnosis and treatment of cystic pancreatic neoplasms

      Abbreviations:

      ASGE (American Society for Gastrointestinal Endoscopy), CEA (carcinoembryonic antigen), EUS-FNA (EUS-guided FNA), IPMN (intraductal papillary mucinous neoplasm), MPD (main pancreatic duct)
      This is one of a series of statements discussing the use of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy (ASGE) prepared this text. In preparing this guideline, a search of the medical literature from January 1990 to September 2015 was performed by using PubMed. Additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. When limited or no data existed from well-designed prospective trials, emphasis was given to results from large series and reports from recognized experts. Guidelines for appropriate use of endoscopy are based on a critical review of the available data and expert consensus at the time the guidelines were drafted. Further controlled clinical studies may be needed to clarify aspects of this guideline. This guideline may be revised as necessary to account for changes in technology, new data, or other aspects of clinical practice. The recommendations were based on reviewed studies and were graded on the strength of the supporting evidence (Table 1).
      • Guyatt G.H.
      • Oxman A.D.
      • Vist G.E.
      • et al.
      GRADE: an emerging consensus on rating quality of evidence and strength of recommendations.
      Table 1GRADE system for rating the quality of evidence for guidelines
      Adapted from Guyatt et al.
      • Guyatt G.H.
      • Oxman A.D.
      • Vist G.E.
      • et al.
      GRADE: an emerging consensus on rating quality of evidence and strength of recommendations.
      Quality of evidenceDefinitionSymbol
      HighFurther research is very unlikely to change our confidence in the estimate of effect.⊕⊕⊕⊕
      ModerateFurther research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.⊕⊕⊕Ο
      LowFurther research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.⊕⊕ΟΟ
      Very lowAny estimate of effect is very uncertain.⊕ΟΟΟ
      GRADE, Grading of Recommendations Assessment, Development and Evaluation.
      This guideline is intended to be an educational device to provide information that may assist endoscopists in providing care to patients. This guideline is not a rule and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment. Clinical decisions in any particular case involve a complex analysis of the patient’s condition and available courses of action. Therefore, clinical considerations may lead an endoscopist to take a course of action that varies from these guidelines. This guideline supplements and replaces our previous document on the role of endoscopy in the diagnosis and the management of cystic lesions and inflammatory fluid collections of the pancreas.
      • Jacobson B.C.
      • Baron T.H.
      • Adler D.G.
      • et al.
      ASGE Standards of Practice Committee
      ASGE guideline: The role of endoscopy in the diagnosis and the management of cystic lesions and inflammatory fluid collections of the pancreas.

      Cystic lesions and fluid collections of the pancreas

      Cystic lesions and fluid collections of the pancreas often present a diagnostic and therapeutic challenge. Their pathology ranges from pseudocysts and pancreatic necrosis to benign and malignant neoplasms. Pancreatic cystic lesions may be encountered during the evaluation of a patient with pancreatitis or abdominal pain. However, these lesions are found incidentally in 2.5% of patients undergoing abdominal imaging performed for unrelated reasons, and their frequency increases with age to 10% in those aged ≥70 years
      • de Jong K.
      • Nio C.Y.
      • Mearadji B.
      • et al.
      Disappointing interobserver agreement among radiologists for a classifying diagnosis of pancreatic cysts using magnetic resonance imaging.
      • Laffan T.A.
      • Horton K.M.
      • Klein A.P.
      • et al.
      Prevalence of unsuspected pancreatic cysts on MDCT.
      In the absence of characteristic radiographic features and clinical detail, pancreatic cystic neoplasms can be misclassified as pseudocysts, which are inflammatory pancreatic fluid collections that lack a true epithelial lining.
      • Martin I.
      • Hammond P.
      • Scott J.
      • et al.
      Cystic tumours of the pancreas.
      • Fernandez-del Castillo C.
      • Targarona J.
      • Thayer S.P.
      • et al.
      Incidental pancreatic cysts: clinicopathologic characteristics and comparison with symptomatic patients.
      • Le Borgne J.
      • de Calan L.
      • Partensky C.
      Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases. French Surgical Association.
      This guideline will discuss the role of GI endoscopy in the evaluation and treatment of cystic pancreatic neoplasms. The role of endoscopy in the management of inflammatory fluid collections of the pancreas is addressed in another ASGE guideline.
      • Muthusamy V.R.
      • Chandrasekhara V.
      • Acosta R.D.
      • et al.
      ASGE Standards of Practice Committee
      The role of endoscopy in the diagnosis and treatment of inflammatory pancreatic fluid collections.

      Cystic lesions of the pancreas

      Cystic lesions of the pancreas consist of nonneoplastic cysts and cystic neoplasms, the latter of which include serous cystic neoplasms, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms (IPMNs) (Table 2). In addition, certain pancreatic tumors may contain cystic spaces or regions of cystic degeneration, such as solid-pseudopapillary neoplasms, cystic neuroendocrine tumors, and even ductal adenocarcinomas.
      • Cooper C.L.
      • O'Toole S.A.
      • Kench J.G.
      Classification, morphology and molecular pathology of premalignant lesions of the pancreas.
      Recently, several strategies and guidelines regarding the diagnosis and indications for resection or surveillance of mucinous cystic pancreatic neoplasms have been published elsewhere.
      • Tanaka M.
      • Fernandez-del Castillo C.
      • Adsay V.
      • et al.
      International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas.
      • Das A.
      • Ngamruengphong S.
      • Nagendra S.
      • et al.
      Asymptomatic pancreatic cystic neoplasm: a cost-effectiveness analysis of different strategies of management.
      • Farrell J.J.
      • Fernandez-del Castillo C.
      Pancreatic cystic neoplasms: management and unanswered questions.
      • Scheiman J.M.
      • Hwang J.H.
      • Moayyedi P.
      American Gastroenterological Association technical review on the diagnosis and management of asymptomatic neoplastic pancreatic cysts.
      • Vege S.S.
      • Ziring B.
      • Jain R.
      • et al.
      American Gastroenterological Association institute guideline on the diagnosis and management of asymptomatic neoplastic pancreatic cysts.
      In a retrospective series of 851 individuals undergoing resection of pancreatic cystic neoplasms over 33 years, the most common pathologic diagnoses were IPMNs (38%), mucinous cystic neoplasms (23%), serous cystic neoplasms (16%), and cystic neuroendocrine neoplasms (7%).
      • Valsangkar N.P.
      • Morales-Oyarvide V.
      • Thayer S.P.
      • et al.
      851 resected cystic tumors of the pancreas: a 33-year experience at the Massachusetts General Hospital.
      Lesions that were identified incidentally accounted for an increasing proportion of resections over time (22% from 1978-1989 to 50% from 2005-2011). Symptomatic cystic neoplasms in this series typically presented with abdominal pain, pancreatitis, jaundice, weight loss, malabsorption, nausea, vomiting, early satiety, or a palpable abdominal mass.
      Table 2Characteristics of pancreatic cystic lesions
      PseudocystIPMNMucinous cystic neoplasmSerous cystic neoplasmCystic endocrine neoplasmSolid pseudopapillary neoplasmDuctal adenocarcinoma with cystic degeneration
      Clinical featuresHistory of moderate to severe pancreatitisHistory of pancreatitis, abdominal pain, or found incidentallyUsually found incidentally but can cause abdominal pain and a palpable mass if largeUsually found incidentally but can cause abdominal pain and a palpable mass if largeMay have clinical features of solid pancreatic endocrine neoplasmUsually found incidentally; rarely causes abdominal discomfortPresents with painless jaundice, abdominal/back pain or rarely pancreatitis
      Morphology/ EUS findingsAnechoic, thick-walled, rare septations, regional inflammatory nodes may be seenDilated main pancreatic duct or side branches; may appear as a septated cyst; may have a solid componentMacrocystic, occasionally septated; peripheral calcifications, solid components and regional adenopathy when malignantMicrocystic with a ‘‘honeycomb’’ appearance; rarely has a macrocystic component; central calcificationUnilocular cyst occupies most of neoplasmSolid and cystic componentsPrimarily solid mass with cystic spaces
      Fluid characteristicsThin, muddy-brownViscous or stringy, clearViscous or stringy, clearThin, clear to serosanguineousThin, clearBloody + necrotic debrisBloody ± debris
      Fluid chemistriesElevated amylase, low CEAElevated amylase and CEAElevated CEA, low amylaseLow CEA and amylaseVariableVariableVariable
      CytologyNeutrophils, macrophages, histiocytes; negative staining for mucinMucinous columnar cells with variable atypia; fluid stains positive for mucinMucinous columnar cells with variable atypia; fluid stains positive for mucinCuboidal epithelium that stains positive for glycogenMonomorphic endocrine tumor cells; stains positive for chromagranin and synaptophysinMonomorphic cells with round nuclei and eosinophilic or foamy cytoplasm; stains positive for vimentin and a-1-antitrypsinMalignant adenocarcinoma may be seen, but varying degrees of atypia may be present in the specimen
      Malignant potentialNoneYesYesAlmost none (rare reports)YesYesAlready present
      Data from references 9 and 12.
      IPMN, Intraductal papillary mucinous neoplasm; CEA, carcinoembryonic antigen.

      Diagnosis by EUS

      EUS morphology

      Several EUS findings have been evaluated as diagnostic criteria for pancreatic cystic lesions.
      • Sedlack R.
      • Affi A.
      • Vazquez-Sequeiros E.
      • et al.
      Utility of EUS in the evaluation of cystic pancreatic lesions.
      • Ahmad N.A.
      • Kochman M.L.
      • Lewis J.D.
      • et al.
      Can EUS alone differentiate between malignant and benign cystic lesions of the pancreas?.
      • Aithal G.P.
      • Chen R.Y.
      • Cunningham J.T.
      • et al.
      Accuracy of EUS for detection of intraductal papillary mucinous tumor of the pancreas.
      • Brandwein S.L.
      • Farrell J.J.
      • Centeno B.A.
      • et al.
      Detection and tumor staging of malignancy in cystic, intraductal, and solid tumors of the pancreas by EUS.
      • Cellier C.
      • Cuillerier E.
      • Palazzo L.
      • et al.
      Intraductal papillary and mucinous tumors of the pancreas: accuracy of preoperative computed tomography, endoscopic retrograde pancreatography and endoscopic ultrasonography, and long-term outcome in a large surgical series.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      • Gress F.
      • Michael H.
      • Gelrud D.
      • et al.
      EUS-guided fine-needle aspiration of the pancreas: evaluation of pancreatitis as a complication.
      • Koito K.
      • Namieno T.
      • Nagakawa T.
      • et al.
      Solitary cystic tumor of the pancreas: EUS-pathologic correlation.
      • Song M.H.
      • Lee S.K.
      • Kim M.H.
      • et al.
      EUS in the evaluation of pancreatic cystic lesions.
      • Sugiyama M.
      • Atomi Y.
      • Saito M.
      Intraductal papillary tumors of the pancreas: evaluation with endoscopic ultrasonography.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      • Gress F.
      • Gottlieb K.
      • Cummings O.
      • et al.
      Endoscopic ultrasound characteristics of mucinous cystic neoplasms of the pancreas.
      When surgical histology is used as a reference standard, the diagnostic accuracy of EUS imaging ranges from 40% to 96%. A single prospective study demonstrated that the sensitivity (56%) and specificity (45%) of EUS morphology alone for differentiating mucinous cysts (mucinous cystic neoplasms and IPMNs) from nonmucinous cysts were low, resulting in poor overall accuracy (51%).
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      In a study among experienced endosonographers, the agreement of whether a cyst was neoplastic versus nonneoplastic by EUS morphologic criteria was fair (K = 0.24), with moderate agreement for serous cystic neoplasms (K = 0.46) and for solid components (K = 0.43).
      • Ahmad N.A.
      • Kochman M.L.
      • Brensinger C.
      • et al.
      Interobserver agreement among endosonographers for the diagnosis of neoplastic versus non-neoplastic pancreatic cystic lesions.
      Small cyst size alone does not exclude malignancy. One series of patients referred to a tertiary-care surgical practice reported that 20% of lesions 2 cm or smaller were malignant, and an additional 45% of lesions had malignant potential.
      • Fernandez-del Castillo C.
      • Targarona J.
      • Thayer S.P.
      • et al.
      Incidental pancreatic cysts: clinicopathologic characteristics and comparison with symptomatic patients.
      However, only 1 of 28 (3.5%) asymptomatic lesions <2 cm was malignant.
      • Fernandez-del Castillo C.
      • Targarona J.
      • Thayer S.P.
      • et al.
      Incidental pancreatic cysts: clinicopathologic characteristics and comparison with symptomatic patients.
      Certain EUS features are more predictive of particular types of cystic lesions. Multiple small (<3 mm) compartments within a cystic lesion (also called a microcystic lesion), suggest a serous cystic neoplasm with an accuracy of 92% to 96%,
      • Koito K.
      • Namieno T.
      • Nagakawa T.
      • et al.
      Solitary cystic tumor of the pancreas: EUS-pathologic correlation.
      and this feature is not seen in mucinous cystic neoplasms.
      • O'Toole D.
      • Palazzo L.
      • Hammel P.
      • et al.
      Macrocystic pancreatic cystadenoma: The role of EUS and cyst fluid analysis in distinguishing mucinous and serous lesions.
      A cystic lesion without septations or solid components within a pancreas having parenchymal features suggestive of pancreatitis (defined as calcifications, atrophy, or a change in echo texture) indicates a pseudocyst with a sensitivity of 94% and a specificity of 85%.
      • Song M.H.
      • Lee S.K.
      • Kim M.H.
      • et al.
      EUS in the evaluation of pancreatic cystic lesions.
      EUS imaging cannot reliably distinguish benign from malignant IPMNs.
      • Cellier C.
      • Cuillerier E.
      • Palazzo L.
      • et al.
      Intraductal papillary and mucinous tumors of the pancreas: accuracy of preoperative computed tomography, endoscopic retrograde pancreatography and endoscopic ultrasonography, and long-term outcome in a large surgical series.
      • Song M.H.
      • Lee S.K.
      • Kim M.H.
      • et al.
      EUS in the evaluation of pancreatic cystic lesions.
      • Sugiyama M.
      • Atomi Y.
      • Saito M.
      Intraductal papillary tumors of the pancreas: evaluation with endoscopic ultrasonography.
      • Kubo H.
      • Chijiiwa Y.
      • Akahoshi K.
      • et al.
      Intraductal papillary-mucinous tumors of the pancreas: differential diagnosis between benign and malignant tumors by endoscopic ultrasonography.
      Furthermore, it is unclear whether imaging features of mucinous lesions with increased malignant potential are sufficiently predictive to influence clinical management. A meta-analysis of 23 studies with 1373 patients found that a mural nodule, main pancreatic duct dilation, thickened septal walls, and cyst size >3 cm on radiologic or EUS imaging were independent predictors of malignant branch-duct IPMN.
      • Kim K.W.
      • Park S.H.
      • Pyo J.
      • et al.
      Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis.
      Similarly, a recent international consensus guideline identified a main pancreatic duct (MPD) size ≥10 mm or the presence of an enhancing solid component on radiologic imaging as high-risk stigmata.
      • Tanaka M.
      • Fernandez-del Castillo C.
      • Adsay V.
      • et al.
      International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas.
      Lower risk findings, categorized as worrisome features, included a cyst size of ≥3 cm, thickened enhancing cyst walls, nonenhancing mural nodules, MPD size of 5 to 9 mm, an abrupt change in the MPD caliber with upstream pancreatic atrophy, or the presence of peripancreatic lymphadenopathy.
      • Tanaka M.
      • Fernandez-del Castillo C.
      • Adsay V.
      • et al.
      International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas.
      Distinguishing cyst wall nodules that are epithelial (neoplastic) from those that are mucinous (nonneoplastic) is critical to properly risk stratify pancreatic cystic neoplasms. A recent blinded interobserver study found that EUS imaging of intracystic mucus appears as a smooth, well-defined hyperechoic rim with a hypoechoic center compared with the surrounding parenchyma. This feature serves to distinguish mucus from true epithelial nodules, which have ill-defined borders and a hyperechoic center.
      • Zhong N.
      • Zhang L.
      • Takahashi N.
      • et al.
      Histologic and imaging features of mural nodules in mucinous pancreatic cysts.
      Specific adjuncts to standard EUS may further aid in distinguishing between these 2 entities. Intraductal US may identify malignant IPMN by the presence of protruding lesions ≥4 mm.
      • Hara T.
      • Yamaguchi T.
      • Ishihara T.
      • et al.
      Diagnosis and patient management of intraductal papillary-mucinous tumor of the pancreas by using peroral pancreatoscopy and intraductal ultrasonography.
      Contrast-enhanced EUS, which uses a contrast agent to assess the vascularity of lesions, may aid in distinguishing inflammatory cysts from cystic pancreatic neoplasms and vascular epithelial mural nodules from nonvascular mucous in IPMNs.
      • Yamashita Y.
      • Ueda K.
      • Itonaga M.
      • et al.
      Usefulness of contrast-enhanced endoscopic sonography for discriminating mural nodules from mucous clots in intraductal papillary mucinous neoplasms: a single-center prospective study.
      • Ohno E.
      • Hirooka Y.
      • Itoh A.
      • et al.
      Intraductal papillary mucinous neoplasms of the pancreas: differentiation of malignant and benign tumors by endoscopic ultrasound findings of mural nodules.
      • Hocke M.
      • Cui X.W.
      • Domagk D.
      • et al.
      Pancreatic cystic lesions: the value of contrast-enhanced endoscopic ultrasound to influence the clinical pathway.

      FNA

      Cyst fluid sampled by EUS-guided-FNA (EUS-FNA) may be analyzed for cytologic, chemical, and/or molecular studies. Any solid component associated with a cystic lesion or regional lymph nodes can be aspirated for cytology or histology. A prospective multicenter study demonstrated a higher diagnostic yield when a solid component was present on EUS (odds ratio 2.48; P = .028; 95% confidence interval [CI], 1.1-5.6).
      • Lim L.G.
      • Lakhtakia S.
      • Ang T.L.
      • et al.
      Factors determining diagnostic yield of endoscopic ultrasound guided fine-needle aspiration for pancreatic cystic lesions: a multicentre Asian study.
      A dilated pancreatic duct also can be safely targeted for FNA when IPMN is suspected.
      • Brandwein S.L.
      • Farrell J.J.
      • Centeno B.A.
      • et al.
      Detection and tumor staging of malignancy in cystic, intraductal, and solid tumors of the pancreas by EUS.
      • Lai R.
      • Stanley M.W.
      • Bardales R.
      • et al.
      Endoscopic ultrasound-guided pancreatic duct aspiration: diagnostic yield and safety.
      There is no standardized method for EUS-FNA of a cystic lesion, and any available gauge needle can be used. However, viscous mucinous fluid may be difficult to aspirate with smaller needles. Although it has been recommended to completely drain aspirated cystic lesions to potentially avoid infection, it is unclear if this practice is beneficial.
      • Guarner-Argente C.
      • Shah P.
      • Buchner A.
      • et al.
      Use of antimicrobials for EUS-guided FNA of pancreatic cysts: a retrospective, comparative analysis.
      FNA of the cyst wall may provide additional cytologic material and can increase the diagnostic yield for mucinous lesions by as much as 37%.
      • Rogart J.N.
      • Loren D.E.
      • Singu B.S.
      • et al.
      Cyst wall puncture and aspiration during EUS-guided fine needle aspiration may increase the diagnostic yield of mucinous cysts of the pancreas.
      Although the use of a core-biopsy needle for histology has shown utility in confirming a diagnosis of microcystic serous neoplasms,
      • Levy M.J.
      • Smyrk T.C.
      • Reddy R.P.
      • et al.
      Endoscopic ultrasound-guided trucut biopsy of the cyst wall for diagnosing cystic pancreatic tumors.
      this practice is rarely required because imaging alone is often diagnostic for these tumors. A recent study demonstrated that the addition of EUS-FNA to CT and magnetic resonance imaging increased the overall accuracy for diagnosing cystic pancreatic neoplasms by 36% and 54%, respectively.
      • Khashab M.A.
      • Kim K.
      • Lennon A.M.
      • et al.
      Should we do EUS/FNA on patients with pancreatic cysts? The incremental diagnostic yield of EUS over CT/MRI for prediction of cystic neoplasms.
      However, given the suboptimal performance characteristics of cytology and carcinoembryonic antigen (CEA) and the very low prevalence of malignancy in cystic pancreatic neoplasms, controversy exists about which cysts should undergo EUS with or without FNA. At present, the utility of FNA appears greatest in patients with cysts containing the imaging features most associated with malignancy at surgical resection, namely an epithelial nodule or mass lesion, cyst size >3 cm, or main pancreatic duct dilation.
      • Atef E.
      • El Nakeeb A.
      • El Hanafy E.
      • et al.
      Pancreatic cystic neoplasms: predictors of malignant behavior and management.
      • de Castro S.M.
      • Houwert J.T.
      • van der Gaag N.A.
      • et al.
      Evaluation of a selective management strategy of patients with primary cystic neoplasms of the pancreas.
      • Donahue T.R.
      • Hines O.J.
      • Farrell J.J.
      • et al.
      Cystic neoplasms of the pancreas: results of 114 cases.
      • Grobmyer S.R.
      • Cance W.G.
      • Copeland E.M.
      • et al.
      Is there an indication for initial conservative management of pancreatic cystic lesions?.
      • Sawhney M.S.
      • Al-Bashir S.
      • Cury M.S.
      • et al.
      International consensus guidelines for surgical resection of mucinous neoplasms cannot be applied to all cystic lesions of the pancreas.
      • Goh B.K.
      • Tan Y.M.
      • Thng C.H.
      • et al.
      How useful are clinical, biochemical, and cross-sectional imaging features in predicting potentially malignant or malignant cystic lesions of the pancreas? Results from a single institution experience with 220 surgically treated patients.
      • Huang E.S.
      • Turner B.G.
      • Fernandez-Del-Castillo C.
      • et al.
      Pancreatic cystic lesions: clinical predictors of malignancy in patients undergoing surgery.
      • Lee C.J.
      • Scheiman J.
      • Anderson M.A.
      • et al.
      Risk of malignancy in resected cystic tumors of the pancreas ≤3 cm in size: is it safe to observe asymptomatic patients? A multi-institutional report.

      Cytology

      Two meta-analyses have evaluated the performance characteristics of EUS-FNA to distinguish mucinous from nonmucinous pancreatic cysts. The first included 376 patients from 11 studies (all of whom had a histopathologic diagnosis) and found that cytology from EUS-FNA aspirates had a pooled sensitivity of 63% (95% CI, 56%-70%) and specificity of 88% (95% CI, 83%-93%).
      • Thosani N.
      • Thosani S.
      • Qiao W.
      • et al.
      Role of EUS-FNA-based cytology in the diagnosis of mucinous pancreatic cystic lesions: a systematic review and meta-analysis.
      The second study included 1438 patients from 18 studies and used surgical histology or clinical follow-up of at least 6 months as the reference standard.
      • Thornton G.D.
      • McPhail M.J.
      • Nayagam S.
      • et al.
      Endoscopic ultrasound guided fine needle aspiration for the diagnosis of pancreatic cystic neoplasms: a meta-analysis.
      The pooled sensitivity and specificity for cytology in this study were 54% (95% CI, 49%-59%) and 93% (95% CI, 90%-95%), respectively.
      Cytologic findings suggestive of a pseudocyst include macrophages, histiocytes, and neutrophils. The presence of mucin is suggestive of a mucinous neoplasm and is seen in 35% or more of cases.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      Glycogen-rich cuboidal cells indicate a serous cystic neoplasm but are present only in approximately 10% of cases.
      • Le Borgne J.
      • de Calan L.
      • Partensky C.
      Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases. French Surgical Association.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      Overall, the diagnostic accuracy of cytology from EUS-FNA for cystic lesions ranges from 54% to 97%
      • Aithal G.P.
      • Chen R.Y.
      • Cunningham J.T.
      • et al.
      Accuracy of EUS for detection of intraductal papillary mucinous tumor of the pancreas.
      • Brandwein S.L.
      • Farrell J.J.
      • Centeno B.A.
      • et al.
      Detection and tumor staging of malignancy in cystic, intraductal, and solid tumors of the pancreas by EUS.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      • Lai R.
      • Stanley M.W.
      • Bardales R.
      • et al.
      Endoscopic ultrasound-guided pancreatic duct aspiration: diagnostic yield and safety.
      • Williams D.B.
      • Sahai A.V.
      • Aabakken L.
      • et al.
      Endoscopic ultrasound guided fine needle aspiration biopsy: a large single centre experience.
      and may be lower in smaller cysts.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      Malignancy within a cystic neoplasm can be identified by cytology with 83% to 99% specificity, although reported sensitivities vary from 25% to 88%.
      • Le Borgne J.
      • de Calan L.
      • Partensky C.
      Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases. French Surgical Association.
      • Brandwein S.L.
      • Farrell J.J.
      • Centeno B.A.
      • et al.
      Detection and tumor staging of malignancy in cystic, intraductal, and solid tumors of the pancreas by EUS.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      • Lai R.
      • Stanley M.W.
      • Bardales R.
      • et al.
      Endoscopic ultrasound-guided pancreatic duct aspiration: diagnostic yield and safety.
      • Maire F.
      • Couvelard A.
      • Hammel P.
      • et al.
      Intraductal papillary mucinous tumors of the pancreas: the preoperative value of cytologic and histopathologic diagnosis.
      • Wiersema M.J.
      • Vilmann P.
      • Giovannini M.
      • et al.
      Endosonography-guided fine-needle aspiration biopsy: diagnostic accuracy and complication assessment.
      • Pais S.A.
      • Attasaranya S.
      • Leblanc J.K.
      • et al.
      Role of endoscopic ultrasound in the diagnosis of intraductal papillary mucinous neoplasms: correlation with surgical histopathology.
      A cytology brush (EchoBrush; Cook Endoscopy, Winston-Salem, NC) passed through a 19-gauge needle was designed to improve the diagnostic yield of cyst fluid cytology obtained from EUS-FNA. However, use has been limited because of concerns regarding its low incremental value over standard EUS-FNA and potential increased risk of adverse events.
      • Al-Haddad M.
      • Raimondo M.
      • Woodward T.
      • et al.
      Safety and efficacy of cytology brushings versus standard FNA in evaluating cystic lesions of the pancreas: a pilot study.
      • Bruno M.
      • Bosco M.
      • Carucci P.
      • et al.
      Preliminary experience with a new cytology brush in EUS-guided FNA.
      • Sendino O.
      • Fernandez-Esparrach G.
      • Sole M.
      • et al.
      Endoscopic ultrasonography-guided brushing increases cellular diagnosis of pancreatic cysts: a prospective study.
      • Thomas T.
      • Bebb J.
      • Mannath J.
      • et al.
      EUS-guided pancreatic cyst brushing: a comparative study in a tertiary referral centre.

      Chemistries and tumor markers

      Because of the limited sensitivity of cytology, cyst fluid may be analyzed for levels of amylase, lipase, and tumor markers such as CEA. Unfortunately, reported sensitivities and specificities of chemical analyses have broad ranges, making interpretation difficult.
      • Frossard J.L.
      • Amouyal P.
      • Amouyal G.
      • et al.
      Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      • Hammel P.
      • Levy P.
      • Voitot H.
      • et al.
      Preoperative cyst fluid analysis is useful for the differential diagnosis of cystic lesions of the pancreas.
      A pooled analysis of 12 studies including 450 patients found that amylase levels <250 U/L virtually excluded (specificity 98%) the lesion as a pseudocyst.
      • van der Waaij L.A.
      • van Dullemen H.M.
      • Porte R.J.
      Cyst fluid analysis in the differential diagnosis of pancreatic cystic lesions: a pooled analysis.
      A prospective, multicenter study of 112 pancreatic cysts diagnosed by surgical resection or biopsy found an optimal CEA cutoff of 192 ng/mL for differentiating mucinous from nonmucinous cysts, providing a sensitivity of 75% and a specificity of 84%.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      When morphologic criteria (associated hypoechoic mass and/or macrocystic septations), cytology, and CEA levels (cutoff 192 ng/mL) were taken together, EUS could differentiate mucinous from nonmucinous lesions with 91% sensitivity and 31% specificity.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      Subsequent studies have suggested that lower CEA cut-off levels (≤30 ng/mL) have increased sensitivity for identifying mucinous cysts without sacrificing specificity.
      • Snozek C.L.
      • Mascarenhas R.C.
      • O'Kane D.J.
      Use of cyst fluid CEA, CA19-9, and amylase for evaluation of pancreatic lesions.
      Higher CEA levels increase specificity for the diagnosis of a mucinous cyst but do not correlate with malignancy.
      • Farrell J.J.
      • Fernandez-del Castillo C.
      Pancreatic cystic neoplasms: management and unanswered questions.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.
      • van der Waaij L.A.
      • van Dullemen H.M.
      • Porte R.J.
      Cyst fluid analysis in the differential diagnosis of pancreatic cystic lesions: a pooled analysis.
      Conversely, a CEA <5 ng/mL in one study was seen in only 7% of mucinous cystic neoplasms and all serous cystic neoplasms.
      • O'Toole D.
      • Palazzo L.
      • Hammel P.
      • et al.
      Macrocystic pancreatic cystadenoma: The role of EUS and cyst fluid analysis in distinguishing mucinous and serous lesions.
      A recent meta-analysis of aspirates from EUS-FNA found CEA to have a sensitivity of 63% (95% CI, 59%-67%) and specificity of 88% (95% CI, 83%-91%) for the identification of mucinous cystic tumors.
      • Thornton G.D.
      • McPhail M.J.
      • Nayagam S.
      • et al.
      Endoscopic ultrasound guided fine needle aspiration for the diagnosis of pancreatic cystic neoplasms: a meta-analysis.
      Other tumor markers studied have included CA 19-9, CA 125, CA 72-4, and CA 15-3, but none of these appear accurate enough to provide a definitive diagnosis.
      • Brugge W.R.
      • Lewandrowski K.
      • Lee-Lewandrowski E.
      • et al.
      Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study.

      Cyst fluid DNA and molecular analysis

      Analysis of molecular markers in pancreatic cyst fluid has been proposed to improve on the limitations in diagnostic accuracy by using cytology and chemical and/or tumor marker analysis alone. An initial study evaluated the role of molecular analysis in 113 patients and found that detection of a K-ras mutation was strongly associated with mucinous cysts and that a combined K-ras and allelic loss showed a specificity of 96% for malignancy.
      • Khalid A.
      • Zahid M.
      • Finkelstein S.D.
      • et al.
      Pancreatic cyst fluid DNA analysis in evaluating pancreatic cysts: a report of the PANDA study.
      • Rockacy M.J.
      • Zahid M.
      • McGrath K.M.
      • et al.
      Association between KRAS mutation, detected in pancreatic cyst fluid, and long-term outcomes of patients.
      Subsequent studies, however, found poor agreement between cyst fluid CEA levels and molecular analysis in diagnosing mucinous cysts,
      • Sawhney M.S.
      • Devarajan S.
      • O'Farrel P.
      • et al.
      Comparison of carcinoembryonic antigen and molecular analysis in pancreatic cyst fluid.
      with comparable sensitivities and diagnostic accuracies.
      • Sawhney M.S.
      • Devarajan S.
      • O'Farrel P.
      • et al.
      Comparison of carcinoembryonic antigen and molecular analysis in pancreatic cyst fluid.
      • Al-Haddad M.
      • DeWitt J.
      • Sherman S.
      • et al.
      Performance characteristics of molecular (DNA) analysis for the diagnosis of mucinous pancreatic cysts.
      The combination of CEA and DNA molecular analysis improved diagnostic accuracy compared to either test alone.
      • Sawhney M.S.
      • Devarajan S.
      • O'Farrel P.
      • et al.
      Comparison of carcinoembryonic antigen and molecular analysis in pancreatic cyst fluid.
      • Al-Haddad M.
      • DeWitt J.
      • Sherman S.
      • et al.
      Performance characteristics of molecular (DNA) analysis for the diagnosis of mucinous pancreatic cysts.
      A more recent study demonstrated that integrated molecular analysis of cyst fluid (ie, combining molecular analysis with results of imaging and clinical features) was able to better characterize the malignant potential of pancreatic cysts compared to consensus guidelines for the management of mucinous cysts.
      • Al-Haddad M.A.
      • Kowalski T.
      • Siddiqui A.
      • et al.
      Integrated molecular pathology accurately determines the malignant potential of pancreatic cysts.
      In addition to acquisition of cyst fluid via EUS-FNA, duodenal collection of pancreatic juice for DNA analysis via an echoendoscope after secretin stimulation found GNAS mutations in 64.1% of 78 patients with IPMN compared with none of the 57 control patients.
      • Kanda M.
      • Knight S.
      • Topazian M.
      • et al.
      Mutant GNAS detected in duodenal collections of secretin-stimulated pancreatic juice indicates the presence or emergence of pancreatic cysts.
      Molecular analysis (which requires only 200 μL of fluid) may be most useful in small cysts with nondiagnostic cytology, equivocal cyst fluid CEA results, or when insufficient fluid is present for CEA testing.
      • Al-Haddad M.
      • DeWitt J.
      • Sherman S.
      • et al.
      Performance characteristics of molecular (DNA) analysis for the diagnosis of mucinous pancreatic cysts.
      However, additional research is needed to determine the precise role molecular analysis of cyst fluid will play in evaluating pancreatic cystic lesions.

      Emerging techniques for cyst evaluation

      Recently, direct optical and endomicroscopic examination of pancreatic cysts has become feasible. Intracystic visualization and direct intracystic biopsy specimens through a 19-gauge needle can be obtained with either a reusable 0.9-mm fiberoptic probe or via a dedicated system primarily indicated for single-operator cholangioscopy and pancreatography (SpyGlass; Boston Scientific, Natick, Mass).
      • Aparicio J.R.
      • Martinez J.
      • Niveiro M.
      • et al.
      Direct intracystic biopsy and pancreatic cystoscopy through a 19-gauge needle EUS (with videos).
      • Antillon M.R.
      • Tiwari P.
      • Bartalos C.R.
      • et al.
      Taking SpyGlass outside the GI tract lumen in conjunction with EUS to assist in the diagnosis of a pancreatic cystic lesion (with video).
      Real-time in vivo microscopic imaging via needle-based confocal laser endomicroscopy after intravenous administration of fluorescein (CellVizio; Mauna Kea Technologies, Paris, France) has also been reported. A study of 66 patients that used confocal laser endomicroscopy found that the presence of epithelial villous structures had a sensitivity of 59% and a specificity of 100% for IPMN, mucinous cystic neoplasm, or adenocarcinoma.
      • Konda V.J.
      • Meining A.
      • Jamil L.H.
      • et al.
      A pilot study of in vivo identification of pancreatic cystic neoplasms with needle-based confocal laser endomicroscopy under endosonographic guidance.
      Another study of 31 patients used this device to identify a superficial vascular network pattern seen only in serous cystic neoplasms.
      • Napoleon B.
      • Lemaistre A.I.
      • Pujol B.
      • et al.
      A novel approach to the diagnosis of pancreatic serous cystadenoma: needle-based confocal laser endomicroscopy.
      This resulted in an overall accuracy in identifying serous cystic neoplasms of 87%, with a high rate of interobserver agreement (κ = 0.77).
      • Napoleon B.
      • Lemaistre A.I.
      • Pujol B.
      • et al.
      A novel approach to the diagnosis of pancreatic serous cystadenoma: needle-based confocal laser endomicroscopy.
      The combined findings of mucin (by transneedle cystoscopy), papillary projections, and dark rings on confocal laser endomicroscopy improved diagnostic accuracy compared with either technique alone.
      • Nakai Y.
      • Iwashita T.
      • Park D.H.
      • et al.
      Diagnosis of pancreatic cysts: EUS-guided, through-the-needle confocal laser-induced endomicroscopy and cystoscopy trial: DETECT study.

      Adverse events from EUS

      A recent ASGE guideline addresses adverse events associated with EUS and EUS -FNA.
      • Early D.S.
      • Acosta R.D.
      • Chandrasekhara V.
      • et al.
      ASGE Standards of Practice Committee
      Adverse events associated with EUS and EUS with FNA.
      In a systematic review of 51 studies, adverse events specific to EUS-FNA of pancreatic cystic lesions occurred in 2.7% of 909 patients.
      • Wang K.X.
      • Ben Q.W.
      • Jin Z.D.
      • et al.
      Assessment of morbidity and mortality associated with EUS-guided FNA: a systematic review.
      This number increased to 5% when data were prospectively collected. No patient-specific or cyst-specific characteristics appear to predict the development of an adverse event.
      • Lee L.S.
      • Saltzman J.R.
      • Bounds B.C.
      • et al.
      EUS-guided fine needle aspiration of pancreatic cysts: a retrospective analysis of complications and their predictors.
      The most common adverse events include abdominal pain,
      • Lee L.S.
      • Saltzman J.R.
      • Bounds B.C.
      • et al.
      EUS-guided fine needle aspiration of pancreatic cysts: a retrospective analysis of complications and their predictors.
      • Al-Haddad M.
      • Wallace M.B.
      • Woodward T.A.
      • et al.
      The safety of fine-needle aspiration guided by endoscopic ultrasound: a prospective study.
      • Tarantino I.
      • Fabbri C.
      • Di Mitri R.
      • et al.
      Complications of endoscopic ultrasound fine needle aspiration on pancreatic cystic lesions: final results from a large prospective multicenter study.
      pancreatitis,
      • Wang K.X.
      • Ben Q.W.
      • Jin Z.D.
      • et al.
      Assessment of morbidity and mortality associated with EUS-guided FNA: a systematic review.
      • Lee L.S.
      • Saltzman J.R.
      • Bounds B.C.
      • et al.
      EUS-guided fine needle aspiration of pancreatic cysts: a retrospective analysis of complications and their predictors.
      • Tarantino I.
      • Fabbri C.
      • Di Mitri R.
      • et al.
      Complications of endoscopic ultrasound fine needle aspiration on pancreatic cystic lesions: final results from a large prospective multicenter study.
      and intracystic hemorrhage.
      • Varadarajulu S.
      • Eloubeidi M.A.
      Frequency and significance of acute intracystic hemorrhage during EUS-FNA of cystic lesions of the pancreas.
      • Carrara S.
      • Arcidiacono P.G.
      • Mezzi G.
      • et al.
      Pancreatic endoscopic ultrasound-guided fine needle aspiration: complication rate and clinical course in a single centre.
      Data regarding the use of prophylactic antibiotics in pancreatic cysts after EUS-FNA are equivocal. Although a cyst infection rate of 14% was reported in an initial series of 22 patients undergoing cyst FNA,
      • Wiersema M.J.
      • Vilmann P.
      • Giovannini M.
      • et al.
      Endosonography-guided fine-needle aspiration biopsy: diagnostic accuracy and complication assessment.
      another retrospective study found only a single infection in 603 patients undergoing EUS-FNA of pancreatic cysts, including no infections in 60 patients who did not receive antibiotic prophylaxis.
      • Lee L.S.
      • Saltzman J.R.
      • Bounds B.C.
      • et al.
      EUS-guided fine needle aspiration of pancreatic cysts: a retrospective analysis of complications and their predictors.
      A recent retrospective cohort study of antibiotic prophylaxis for EUS-FNA of pancreatic cysts identified 1 possible infection each in 88 patients treated with antibiotics and 178 patients given no antibiotics.
      • Guarner-Argente C.
      • Shah P.
      • Buchner A.
      • et al.
      Use of antimicrobials for EUS-guided FNA of pancreatic cysts: a retrospective, comparative analysis.
      Nevertheless, current ASGE guidelines suggest administration of antibiotics for 3 to 5 days after EUS-FNA of a pancreatic cystic lesion.
      • Khashab M.A.
      • Chithadi K.V.
      • Acosta R.D.
      • et al.
      ASGE Standards of Practice Committee
      Antibiotic prophylaxis for GI endoscopy.

      Diagnosis by ERCP

      ERCP is rarely indicated for the evaluation of pancreatic cystic lesions. In main-duct IPMN, duodenoscopy may reveal the highly specific finding of mucus extruding from a patulous pancreatic orifice.
      • Azar C.
      • Van de Stadt J.
      • Rickaert F.
      • et al.
      Intraductal papillary mucinous tumours of the pancreas. Clinical and therapeutic issues in 32 patients.
      This pathognomonic finding is seen in 20% to 55% of patients with main-duct IPMN and was seen more frequently in malignant disease in some, but not all, studies.
      • Hara T.
      • Yamaguchi T.
      • Ishihara T.
      • et al.
      Diagnosis and patient management of intraductal papillary-mucinous tumor of the pancreas by using peroral pancreatoscopy and intraductal ultrasonography.
      • Maire F.
      • Couvelard A.
      • Hammel P.
      • et al.
      Intraductal papillary mucinous tumors of the pancreas: the preoperative value of cytologic and histopathologic diagnosis.
      • Azar C.
      • Van de Stadt J.
      • Rickaert F.
      • et al.
      Intraductal papillary mucinous tumours of the pancreas. Clinical and therapeutic issues in 32 patients.
      • Kitagawa Y.
      • Unger T.A.
      • Taylor S.
      • et al.
      Mucus is a predictor of better prognosis and survival in patients with intraductal papillary mucinous tumor of the pancreas.
      A pancreaticoduodenal fistula extruding mucous is seen in up to 2% of IPMN cases and suggests malignant invasion.
      • Telford J.J.
      • Carr-Locke D.L.
      The role of ERCP and pancreatoscopy in cystic and intraductal tumors.
      Pancreatography has limited utility in the assessment of cystic neoplasms. In the absence of other risk factors for ductal stenosis, such as chronic pancreatitis or pancreatic trauma, a narrowed pancreatic duct suggests malignancy.
      • Telford J.J.
      • Carr-Locke D.L.
      The role of ERCP and pancreatoscopy in cystic and intraductal tumors.
      Communication with the MPD suggests either a pseudocyst or an IPMN and is rare in mucinous or serous cystic neoplasms. Pancreatographic findings of chronic pancreatitis, such as ectatic or blunted side branches favor the diagnosis of pseudocyst, but can be seen in IPMN as well. Other features of IPMN include segmental or diffuse dilatation of the MPD or focal side-branch dilatation. Filling defects in the MPD caused by mucus may be distinguished from stones by their transient nature and movement when passed with contrast material injection, a catheter, or a guidewire. Persistent filling defects that represent polypoid lesions also may be seen.
      • Telford J.J.
      • Carr-Locke D.L.
      The role of ERCP and pancreatoscopy in cystic and intraductal tumors.
      Pancreatoscopy in IPMN may be facilitated by an enlarged papillary opening and provides direct visualization of mucus, stones, or a tumor. Direct examination of the main duct may determine the extent of disease and guide biopsy specimens. One study found the combination of pancreatoscopy, and intraductal US was capable of distinguishing benign from malignant IPMNs with an accuracy of 88%.
      • Hara T.
      • Yamaguchi T.
      • Ishihara T.
      • et al.
      Diagnosis and patient management of intraductal papillary-mucinous tumor of the pancreas by using peroral pancreatoscopy and intraductal ultrasonography.
      Another study of 44 patients undergoing single-operator pancreatoscopy when radiologic imaging suggested IPMN found 76% and 78% of surgically confirmed main duct and side-branch IPMNs were correctly identified by pancreatoscopy.
      • Arnelo U.
      • Siiki A.
      • Swahn F.
      • et al.
      Single-operator pancreatoscopy is helpful in the evaluation of suspected intraductal papillary mucinous neoplasms (IPMN).
      Furthermore, the pancreatoscopy results impacted clinical decision making in 76% of cases.
      ERCP-directed tissue sampling of main duct IPMNs includes the evaluation of aspirated mucus, brush cytology, biopsy specimens of fixed filling defects or strictures, and random biopsy specimens of dilated duct walls. In 1 study, transpapillary biopsy with standard or pediatric-sized forceps yielded a histopathologic diagnosis of IPMN in 11 of 13 patients.
      • Maire F.
      • Couvelard A.
      • Hammel P.
      • et al.
      Intraductal papillary mucinous tumors of the pancreas: the preoperative value of cytologic and histopathologic diagnosis.
      However, in general, ERCP tissue sampling has a relatively low diagnostic yield. A systematic review of 13 studies totaling 483 patients with IPMN found a pooled sensitivity of 35.1% and a specificity of 97.2% for ERCP-based cytology, with lavage cytology showing minimal improved sensitivity (45.8%) compared with fluid aspiration (41.5%) but increased sensitivity compared with brushings (20.9%).
      • Suzuki R.
      • Thosani N.
      • Annangi S.
      • et al.
      Diagnostic yield of endoscopic retrograde cholangiopancreatography-based cytology for distinguishing malignant and benign intraductal papillary mucinous neoplasm: systematic review and meta-analysis.
      Several reports have described pancreatoscopy by using a videoscope with narrow-band imaging or via a fiberoptic probe to obtain tissue or cytology.
      • Yamaguchi T.
      • Shirai Y.
      • Ishihara T.
      • et al.
      Pancreatic juice cytology in the diagnosis of intraductal papillary mucinous neoplasm of the pancreas: significance of sampling by peroral pancreatoscopy.
      • Miura T.
      • Igarashi Y.
      • Okano N.
      • et al.
      Endoscopic diagnosis of intraductal papillary-mucinous neoplasm of the pancreas by means of peroral pancreatoscopy using a small-diameter videoscope and narrow-band imaging.
      • Itoi T.
      • Sofuni A.
      • Itokawa F.
      • et al.
      Initial experience of peroral pancreatoscopy combined with narrow-band imaging in the diagnosis of intraductal papillary mucinous neoplasms of the pancreas (with videos).
      • Nagayoshi Y.
      • Aso T.
      • Ohtsuka T.
      • et al.
      Peroral pancreatoscopy using the SpyGlass system for the assessment of intraductal papillary mucinous neoplasm of the pancreas.
      Its use has been shown to result in an absolute increase in the sensitivity of lavage cytology for malignancy in main duct IPMN by 24% compared with fluid aspiration with a catheter.
      • Yamaguchi T.
      • Shirai Y.
      • Ishihara T.
      • et al.
      Pancreatic juice cytology in the diagnosis of intraductal papillary mucinous neoplasm of the pancreas: significance of sampling by peroral pancreatoscopy.

      Endoscopic treatment of cystic lesions

      Recently, endoscopic cyst ablation with ethanol alone or in combination with paclitaxel for suspected pancreatic cystic neoplasms has been proposed as an alternative to surgery.
      • DeWitt J.
      • McGreevy K.
      • Schmidt C.M.
      • et al.
      EUS-guided ethanol versus saline solution lavage for pancreatic cysts: a randomized, double-blind study.
      • Gan S.I.
      • Thompson C.C.
      • Lauwers G.Y.
      • et al.
      Ethanol lavage of pancreatic cystic lesions: initial pilot study.
      • Oh H.C.
      • Seo D.W.
      • Lee T.Y.
      • et al.
      New treatment for cystic tumors of the pancreas: EUS-guided ethanol lavage with paclitaxel injection.
      • Oh H.C.
      • Seo D.W.
      • Song T.J.
      • et al.
      Endoscopic ultrasonography-guided ethanol lavage with paclitaxel injection treats patients with pancreatic cysts.
      Cysts selected for ablation have typically been less than 3 to 4 cm in size, unilocular or oligolocular (<3-6 locules), and without evidence of communication with the MPD. A randomized trial showed that ethanol is superior to saline solution for pancreatic cyst ablation.
      • DeWitt J.
      • McGreevy K.
      • Schmidt C.M.
      • et al.
      EUS-guided ethanol versus saline solution lavage for pancreatic cysts: a randomized, double-blind study.
      • Oh H.C.
      • Brugge W.R.
      EUS-guided pancreatic cyst ablation: a critical review (with video).
      The chemotherapeutic agent paclitaxel has been added in more recent studies to standard ethanol lavage to potentially improve response rates. The hydrophobic nature of paclitaxel is believed to foster its retention in the cyst and minimize peri-cystic leakage. Overall reported rates of cyst resolution range from 33% to 79%, with increased efficacy observed with smaller initial cyst volumes, multiple ethanol ablations, or ethanol and/or paclitaxel combination therapy.
      • Oh H.C.
      • Seo D.W.
      • Song T.J.
      • et al.
      Endoscopic ultrasonography-guided ethanol lavage with paclitaxel injection treats patients with pancreatic cysts.
      • Oh H.C.
      • Brugge W.R.
      EUS-guided pancreatic cyst ablation: a critical review (with video).
      • DiMaio C.J.
      • DeWitt J.M.
      • Brugge W.R.
      Ablation of pancreatic cystic lesions: the use of multiple endoscopic ultrasound-guided ethanol lavage sessions.
      Adverse events have been reported in approximately 12% of cases and include abdominal pain, focal peritonitis, pancreatitis, fever, pericystic spillage, splenic vein obliteration, and portal venous thrombosis.
      • Oh H.C.
      • Brugge W.R.
      EUS-guided pancreatic cyst ablation: a critical review (with video).
      • Oh H.C.
      • Seo D.W.
      • Kim S.C.
      Portal vein thrombosis after EUS-guided pancreatic cyst ablation.
      Uncertainties remain regarding the durability of the technique,
      • DeWitt J.
      • DiMaio C.J.
      • Brugge W.R.
      Long-term follow-up of pancreatic cysts that resolve radiologically after EUS-guided ethanol ablation.
      whether complete epithelial ablation has been achieved in radiographically resolved cysts and the impact on the malignant potential of these cysts.
      • Gomez V.
      • Takahashi N.
      • Levy M.J.
      • et al.
      EUS-guided ethanol lavage does not reliably ablate pancreatic cystic neoplasms (with video).
      A recent study demonstrated that EUS-guided cyst ablation may eliminate mutant DNA in neoplastic pancreatic cysts.
      • DeWitt J.M.
      • Al-Haddad M.
      • Sherman S.
      • et al.
      Alterations in cyst fluid genetics following endoscopic ultrasound-guided pancreatic cyst ablation with ethanol and paclitaxel.
      However, patients achieving cyst ablation are thought to be at continued risk of developing ductal adenocarcinoma and should undergo continued surveillance imaging.
      • Ingkakul T.
      • Sadakari Y.
      • Ienaga J.
      • et al.
      Predictors of the presence of concomitant invasive ductal carcinoma in intraductal papillary mucinous neoplasm of the pancreas.
      Given these limitations, EUS-guided cyst ablation is performed only at select centers and might be considered for patients who refuse or are not candidates for surgery.

      Recommendations

      • 1.
        We recommend EUS-FNA of any pancreatic cystic lesion over 3 cm in diameter or when cross-sectional or EUS imaging confirms an epithelial nodule, dilated main pancreatic duct, or suspicious mass lesion. ⊕⊕⊕○
      • 2.
        We suggest that EUS-FNA is optional in asymptomatic patients in whom cross-sectional imaging demonstrates a cyst <3 cm and without either a mass and/or epithelial nodule or associated dilated main pancreatic duct. ⊕⊕○○
      • 3.
        We recommend initial testing of aspirated pancreatic cyst fluid for CEA, amylase, and cytology. ⊕⊕⊕○
      • 4.
        We suggest that molecular testing of the cyst be considered when initial ancillary testing of cytology and CEA is inconclusive and when test results may alter management. ⊕⊕○○
      • 5.
        We suggest administration of prophylactic antibiotics for patients undergoing EUS-FNA for the evaluation of cystic pancreatic neoplasms. ⊕⊕○○
      • 6.
        We suggest that ERCP, pancreatoscopy, and intraductal US may be helpful in the diagnosis and characterization of suspected main duct IPMNs. ⊕⊕○○

      Disclosures

      M. Khashab is a consultant for Boston Scientific and Xlumena. V. Muthusamy is a consultant for Boston Scientific. He also received honoraria and research support from Medtronic. K. Chathadi is a consultant for Boston Scientific. All other authors disclosed no financial relationships relevant to this publication.

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