Current status on the diagnosis and management of pancreatic cysts in the Asia-Pacific region: role of endoscopic ultrasound

Endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) play increasingly prominent roles in the diagnosis and management of pancreatic cysts. The Asian Consortium of Endoscopic Ultrasound was recently formed to conduct collaborative research in this area. This is a review of literature on true pancreatic cysts. Due to the lack of systematic studies, there are no robust data on the true incidence of pancreatic cystic lesions in Asia and any change in over the recent decades. Certain EUS morphological features have been used to predict particular types of pancreatic cysts. Pancreatic cyst fluid viscosity, cytology, pancreatic enzymes, and tumor markers, in particular carcinoembryonic antigen, can aid in the diagnosis of pancreatic cysts. Hemorrhage and infection are the most common complications of EUS-FNA of pancreatic cysts. Pancreatic cysts can either be observed or resected depending on the benign or malignant nature, or malignant potential of the lesions. Guidelines from an international consensus did not require positive cytological findings to be present in their recommendation for resection, which included all mucinous cystic neoplasms, all main-duct intraductal papillary mucinous neoplasms (IPMN), all mixed IPMN, symptomatic side-branch IPMN, and side-branch IPMN larger than 3 cm. In patients with poor surgical risks, EUS-guided cyst ablation of mucinous pancreatic cysts is an alternative. As long-term prospective data on pancreatic cysts are still not available in Asia, management strategies are largely based on risk stratification by surgical risk and malignant potential. Gene expression profiling of pancreatic cyst fluid and confocal laser endomicroscopic examination of pancreatic cysts are novel techniques currently being studied.     

Endosonography in the diagnosis and management of pancreatic cysts

Rapid advances in radiologic technology and increased cross-sectional imaging have led to a sharp rise in incidental discoveries of pancreatic cystic lesions. These cystic lesions include non-neoplastic cysts with no risk of malignancy, neoplastic non-mucinous serous cystadenomas with little or no risk of malignancy, as well as neoplastic mucinous cysts and solid pseudopapillary neoplasms both with varying riskof malignancy. Accurate diagnosis is imperative as management is guided by symptoms and risk of malignancy. Endoscopic ultrasound(EUS) allows high resolution evaluation of cyst morphology and precise guidance for fine needle aspiration(FNA) of cyst fluid for cytological, chemical and molecular analysis. Initially, clinical evaluation and radiologic imaging, preferably with magnetic resonance imaging of the pancreas and magnetic resonance cholangiopancreatography, are performed. In asymptomatic patients where diagnosis is unclear and malignant risk is indeterminate, EUSFNA should be used to confirm the presence or absence of high-risk features, differentiate mucinous from non-mucinous lesions, and diagnose malignancy. After analyzing the cyst fluid for viscosity, cyst fluid carcinoembryonic antigen, amylase, and cyst wall cytology should be obtained. DNA analysis may add useful information in diagnosing mucinous cysts when the previous studies are indeterminate. New molecular biomarkers are being investigated to improve diagnostic capabilities and management decisions in these challenging cystic lesions. Current guidelines recommend surgical pancreatic resection as the standard of care for symptomatic cysts and those with high-risk features associated with malignancy. EUSguided cyst ablation is a promising minimally invasive, relatively low-risk alternative to both surgery and surveillance.     

Concomitant pancreatic adenocarcinoma in a patient with branch-duct intraductal papillary mucinous neoplasm

Branch duct intraductal papillary mucinous neoplasms (BD-IPMN) are pre-malignant pancreatic cystic lesions which carry a small risk of malignant transformation within the cyst. Guidelines exist with respect to surveillance of the cysts using computed tomography, magnetic resonance imaging, and/or endoscopic ultrasound (EUS). There are reports that patients with IPMNs are at increased risk of developing pancreatic adenocarcinoma, which arises in an area separate to the IPMNs. We present two cases of pancreatic adenocarcinoma arising within the parenchyma, distinct from the IPMN-associated cyst, identified with EUS. This case report highlights that patients with BD-IPMN are at increased risk for pancreatic adenocarcinoma separate from the cyst and also the importance for endosonographers to carefully survey the rest of the pancreatic parenchyma separate from the cyst in order to identify small pancreatic adenocarcinomas.     

Pancreatic Cysts and Guidelines

Pancreatic cysts, especially incidental asymptomatic ones seen on noninvasive imaging such as CT or MR imaging, remain a clinical challenge. The etiology of such cysts may range from benign cysts without any malignant potential such as pancreatic pseudocysts and serous cystadenomas to premalignant or frankly malignant cysts such as mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, cystic degeneration associated with solid tumors such as pancreatic ductal adenocarcinoma or pancreatic endocrine neoplasms, and solid pseudopapillary neoplasms. The clinical challenge in 2017 is to accurately preoperatively diagnose them and their malignant potential before deciding about surgery, surveillance or doing nothing. This review will focus on the currently available clinical guidelines for doing so.     

Serous cystic neoplasm of the pancreas-indications for surgery

BACKGROUND/AIMS: Serous cystic neoplasm is a rare pancreatic tumor. Almost all of these tumors are benign and only 9 cases of serous cystadenocarcinoma have been reported. Although serous cystic neoplasm is typically a microcystic lesion, there is a wide range of cyst sizes from micro to macro and even unilocular cysts have been reported. Thus, the diagnosis is difficult and indications for surgery are controversial. We aimed to elucidate the clinicopathological and imaging features of serous cystic neoplasm of the pancreas. METHODOLOGY: We investigated 15 cases of resected and 6 cases of nonresected cases of serous cystic neoplasm, evaluating the symptoms, imaging findings, preoperative diagnosis, macroscopic morphology, microscopic findings, and results of follow-up. RESULTS: Imaging diagnosis of serous cystic neoplasm was not easy, because not so many tumors had the typical microcystic pattern. Most of the resected serous cystic neoplasms were non-microcystic or were small tumors, which could not be precisely evaluated. CONCLUSIONS: Small serous cystic neoplasms, which can be diagnosed by imaging, do not need to be resected because serous cystadenocarcinoma is rare. Tumors of the pancreas that cannot be confirmed to be serous cystic neoplasm should be resected because of the possibility of pancreatic cancer, mucinous cystadenocarcinoma, or mucinous cystadenoma with malignant potential.     

Cystic Lesions of the Pancreas: A Diagnostic and Management Dilemma

Background/Aims: Due to enhanced imaging modalities, pancreatic cysts are being increasingly detected, often as an incidental finding. They comprise a wide range of differing underlying pathologies from completely benign through premalignant to frankly malignant. The exact diagnostic and management pathway of these cysts remains problematic and this review attempts to provide an overview of the pathology underlying pancreatic cystic lesions and suggests appropriate methods of management. Methods: A search was undertaken with a Pubmed database to identify all English articles using the keywords ‘pancreatic cysts’, ‘serous cystadenoma’, ‘intraductal papillary mucinous tumour’, ‘pseudocysts’, ‘mucinous cystic neoplasm’ and ‘solid pseudopapillary tumour’. Results: The mainstay of assessment of pancreatic cysts is cross-sectional imaging incorporating CT and MRI. Fine-needle aspiration (FNA) (often with endoscopic ultrasound) may provide valuable additional information but can lack sensitivity. Symptomatic cysts, increasing age and multilocular cysts (with a solid component and thick walls) are predictors of malignancy. A raised cyst aspirate CEA, CA 19-9 and mucin content (including abnormal cytology), if present, can accurately distinguish premalignant and malignant cysts from benign ones. Conclusion: In summary, all patients with pancreatic cystic lesions, whether asymptomatic or symptomatic, must be thoroughly investigated to ascertain the underlying nature of the cyst. Small asymptomatic cysts (<3 cm) with no suspicious features on imaging or FNA may be safely followed up. Follow-up should continue for at least 4 years, with a repeat FNA if needed. An algorithm for the management of pancreatic cystic tumours is also suggested.     

Cyst fluid analysis obtained by EUS-guided FNA in the evaluation of discrete cystic neoplasms of the pancreas: a prospective single-center experience

BACKGROUND: Accurate assessment of pancreatic cystic neoplasms is imperative before selecting available treatment options, such as surgical resection, drainage, or conservative therapy. Available modalities, CT and magnetic resonance imaging, have been inconsistent in diagnosis. Reports involving EUS and cyst fluid analysis have been encouraging, including studies of EUS features and/or cyst fluid analysis, which may differentiate pancreatic cystic neoplasms. OBJECTIVE: To retrospectively determine cyst fluid characteristics that differentiate cystic neoplasms. DESIGN: Patient evaluation included (1) EUS features (reported elsewhere) and (2) cyst fluid analysis (carcinoembryonic antigen [CEA], carbohydrate antigen 19-9 [CA 19-9], amylase and lipase, viscosity [VIS], mucin stain, and cytology). Exclusion criteria included the following: intraductal papillary mucinous tumor lesions, bloody cyst aspirate, neuroendocrine tumors, and patients without surgical histopathology. SETTING: Pancreatic Biliary Center, St Luke's Medical Center, Milwaukee, Wisconsin. PATIENTS: A total of 102 patients (60 women, 42 men; age, 23-76 years) presented for evaluation of pancreatic cystic neoplasm; 71 underwent surgical resection. RESULTS: Seventy-one of 102 patients who underwent surgery presented the following histopathologic correlates: 23 pseudocysts (PC), 13 serous cystadenoma (SCyA), 21 mucinous cystadenoma (MCyA), and 14 mucinous cystadenocarcinoma (MCyA-CA). Cyst fluid analysis of these patients showed the following: VIS was lower in PC (mean, 1.3) and SCyA (1.27) when compared with MCyA (1.84) and MCyA-CA (1.9). All mucinous neoplasms had VIS >1.6, whereas only 2 mucinous cystic neoplasms (MCN) had VIS = 1.6 (both PC). The CEA level was significantly higher in MCyA (adenoma [878 ng/mL], carcinoma [27,581 ng/mL]) vs PC (189 ng/mL), and SCyA (121 ng/mL). Amylase levels were higher in PC (7210 U/L) compared with cystic neoplasm (SCyA, 679 U/L; MCyA, 1605 U/L; MCyA-CA, 569 U/L). CONCLUSIONS: Differential diagnosis of pancreatic cystic neoplasm is significantly enhanced by cyst fluid analysis. Elevated CEA (> or =480 ng/mL) and VIS (>1.6) accurately predict MCN from SCyA and PC. Malignant from benign MCN can be differentiated by CEA levels > or =6000 ng/mL.     

Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study

BACKGROUND & AIMS: Cysts of the pancreas display a wide spectrum of histology, including inflammatory (pseudocysts), benign (serous), premalignant (mucinous), and malignant (mucinous) lesions. Endoscopic ultrasonography (EUS) may offer a diagnostic tool through the combination of imaging and guided, fine-needle aspiration (FNA). The purpose of this investigation was to determine the most accurate test for differentiating mucinous from nonmucinous cystic lesions. METHODS: The results of EUS imaging, cyst fluid cytology, and cyst fluid tumor markers (CEA, CA 72-4, CA 125, CA 19-9, and CA 15-3) were prospectively collected and compared in a multicenter study using histology as the final diagnostic standard. RESULTS: Three hundred forty-one (341) patients underwent EUS and FNA of a pancreatic cystic lesion; 112 of these patients underwent surgical resection, providing a histologic diagnosis of the cystic lesion (68 mucinous, 7 serous, 27 inflammatory, 5 endocrine, and 5 other). Receiver operator curve analysis of the tumor markers demonstrated that cyst fluid CEA (optimal cutoff of 192 ng/mL) demonstrated the greatest area under the curve (0.79) for differentiating mucinous vs. nonmucinous cystic lesions. The accuracy of CEA (88 of 111, 79%) was significantly greater than the accuracy of EUS morphology (57 of 112, 51%) or cytology (64 of 109, 59%) (P < 0.05). There was no combination of tests that provided greater accuracy than CEA alone (P < 0.0001). CONCLUSIONS: Of tested markers, cyst fluid CEA is the most accurate test available for the diagnosis of mucinous cystic lesions of the pancreas.     

Molecular assessment of endoscopically collected pancreatic juice and duodenal fluid from patients with pancreatic diseases

One concern associated with pancreatic diseases is the poor prognosis of pancreatic cancer. Even with advances in diagnostic modalities, risk stratification of premalignant lesions and differentiation of pancreatic cysts are challenging. Pancreatic lesions of concern include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystadenomas, pseudocysts, and retention cysts, as well as cystic degeneration of solid tumors such as solid pseudopapillary neoplasms and pancreatic neuroendocrine neoplasms. Pancreatic juice obtained during endoscopic retrograde cholangiopancreatography has previously been used for the detection of KRAS mutation. Recently, duodenal fluid, which can be obtained during the relatively minimally invasive procedures of endoscopic ultrasound (EUS) and esophagogastroduodenoscopy, and cyst fluid collected by EUS-guided fine-needle aspiration (FNA) were used for molecular biological analysis. Furthermore, advanced analytic methods with high sensitivity were used for the detection of single and multiple markers. Early detection of malignant pancreatic tumors and risk stratification of premalignant tumors can be performed using duodenal fluid samples with a single marker with high sensitivity. Technological advances in simultaneous detection of multiple markers allow for the differentiation of cystic pancreatic tumors. One thing to note is that the clinical guidelines do not recommend pancreatic cyst fluid and pancreatic juice (PJ) sampling by EUS-FNA and endoscopic retrograde cholangiopancreatography, respectively, in actual clinical practice, but state that they be performed at experienced facilities, and duodenal fluid sampling is not mentioned in the guidelines. With improved specimen handling and the combination of markers, molecular markers in PJ samples may be used in clinical practice in the near future.     

Appraisal of needle-based confocal laser endomicroscopy in the diagnosis of pancreatic cysts

Nearly 2.5% of cross-sectional imaging studies will report a finding of a cystic pancreatic lesion. Eventhough most of these are incidental findings, it remains very concerning for both patients and treating clinicians. Differentiating and predicting malignant transformation in pancreatic cystic lesions is clinically challenging. Current evaluation of suspicious cystic lesions includes a combination of radiologic imaging, endoscopic ultrasound(EUS) and cyst fluid analyses. Despite these attempts, precise diagnostic stratification among nonmucinous, mucinous, and malignant cystic lesions is often not possible until surgical resection. EUS-guided needle based confocal laser endomicroscopy(n CLE) for evaluation of pancreatic cysts is emerging as a powerful technique with remarkable potential. Though limited imaging data from 3 large clinical trials(INSPECT, DETECT and CONTACT) are currently the reference standard for n CLE imaging, nonetheless these have not been validated in large studies. The aim of this review article is to review the evolving role of EUS-guided n CLE in management of pancreatic cystic lesions in terms of its significance, adverse events, limitations, and implications.     

Management of mucinous cystic neoplasms of the pancreas

The purpose of this study was to investigate the actual management of mucinous cystic neoplasm (MCN) of the pancreas. A systematic review was performed in December 2009 by consulting PubMed MEDLINE for publications and matching the "pancreatic mucinous cystic neoplasm", "pancreatic mucinous cystic tumour", "pancreatic mucinous cystic mass", "pancreatic cyst", and "pancreatic cystic neoplasm" to identify English language articles describing the diagnosis and treatment of the mucinous cystic neoplasm of the pancreas. In total, 16 322 references ranging from January 1969 to December 2009 were analysed and 77 articles were identified. No articles published before 1996 were selected because MCNs were not previously considered to be a completely autonomous disease. Definition, epidemiology, anatomopathological findings, clinical presentation, preoperative evaluation, treatment and prognosis were reviewed. MCNs are pancreatic mucinproducing cysts with a distinctive ovarian-type stroma localized in the body-tail of the gland and occurring in middle-aged females. The majority of MCNs are slow growing and asymptomatic. The prevalence of invasive carcinoma varies between 6% and 55%. Preoperative diagnosis depends on a combination of clinical features, tumor markers, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound with cyst fluid analysis, and positron emission tomography-CT. Surgery is indicated for all MCNs.     

Endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic cysts by combined cytopathology and cystic content analysis

Recent advances in imaging technology have resulted in an increase in incidental discoveries of pancreatic cystic lesions. Pancreatic cysts comprise a wide variety of lesions and include non-neoplastic cysts and neoplastic cysts. Because some pancreatic cysts have more of a malignant potential than others, it is absolutely essential that an accurate diagnosis is rendered so that effective care can be given to each patient. In many centers, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has emerged as the modality of choice that enables one to distinguish between mucinous and non-mucinous lesion, diagnose malignancy and collect cyst fluid for further diagnostic studies, such as pancreatic enzyme levels, molecular analysis and other tumor biomarkers. The current review will focus on EUS-guided FNA and the cytological diagnosis for pancreatic cysts.     

Utility of endoscopic ultrasound, cytology and fluid carcinoembryonic antigen and CA 19-9 levels in pancreatic cystic lesions

AIM： To assess the diagnostic accuracy of endoscopic ultrasound （EUS）, fluid tumor markers and cytology in distinguishing benign from （pre）malignant pancreatic cystic lesions.
METHODS： 46 consecutive patients, referred to a gastroenterologist and surgeon for a symptomatic or incidental pancreatic cyst, were reviewed. EUS, cytology, and carcinoembryonic antigen （CEA） and carbohydrate antigen （CA 19-9） levels were compared with the final diagnosis, based on surgical pathology and/or imaging follow-up of at least 12 mo. Cysts were classified as benign （pseudocyst, serous cystadenoma） or malignant/ pre-malignant （mucinous cystic neoplasm）. Receiver- operator characteristics （ROC） curve analysis was performed. RESULTS： The mean age was 56 years; 29% were male and median cyst diameter was 3 cm. Final outcome was obtained in 41 （89%） patients. Twenty-three （56%） of these 41 had surgical pathology. Twenty-three （56%） had benign lesions and 18 （44%） had malignant/premalignant lesions. Sensitivity, specificity and positive and negative predictive value of EUS alone to distinguish benign from malignant/premalignant pancreatic cystic lesions were 50%, 56%, 36% and 54% and for cytology were 71%, 96%, 92% and 85%, respectively. The corresponding values for the ROC-derived ideal cutoffs were 75%, 90%, 75%, 90% for CA 19-9 （〉 37 U/mL） and 70%, 85%, 79% and 78% for CEA （〉 3.1 ng/mL）. Subgroup analysis of those with surgical pathology yielded almost identical performance and cutoffs.
CONCLUSION： Cytology and cyst fluid tumor marker analysis is a very useful tool in distinguishing benign from （pre）malignant pancreatic cystic lesions.     

Endoscopic ultrasound characteristics of mucinous cystic neoplasms of the pancreas

OBJECTIVE: Mucinous cystic neoplasms of the pancreas have a more favorable prognosis than ductal adenocarcinoma. Management of a subgroup, intraductal papillary-mucinous neoplasms, is controversial. Endoscopic ultrasound (EUS) with fine-needle aspiration biopsy may emerge as the imaging modality of choice. There are few studies describing the EUS features of these tumors. METHODS: A total of 35 consecutive cases of cystic tumors of the pancreas with an established pathological diagnosis were analyzed for characteristic EUS features. RESULTS: Mucinous cystadenocarcinomas (n = 14) were more likely to be characterized by hypoechoic cystic/solid mass or complex cyst and were frequently associated with a dilated main pancreatic duct. Benign mucinous duct ectasia (n = 6) were characterized by a dilated main pancreatic duct in conjunction with hyperechoic thickening of the duct wall. The two cases of intraductal mucinous hyperplasia additionally showed a hypoechoic mass. Intraductal papillary carcinoma (n = 11) had features in common with mucinous cystadenocarcinoma but also had echogenic foci in the mass and intraductal hyperechoic lesions. The two cases of microcystic cystadenoma showed either a mixed hypoechoic solid/cystic mass or a complex cyst without the additional features seen in mucinous cystadenocarcinoma. CONCLUSIONS: EUS features seem to exist that may help to differentiate cystic neoplasms from adenocarcinoma of the pancreas and, thus, to establish the preoperative diagnosis of cystic tumors of the pancreas.     

胰腺囊性病变的临床特征和诊治分析

背景:随着影像学技术的进步,胰腺囊性病变的检出率逐年升高,但鉴别不同类型的胰腺囊性病变仍是临床的棘手问题。目的:分析胰腺囊性病变的临床特征和诊治方法。方法:纳入2003年1月~2013年1月上海交通大学附属第一人民医院收治的胰腺囊性病变患者,对入组患者的临床表现、实验室检查、影像学特征以及治疗方法进行回顾性分析。结果:共49例患者纳入研究,其中假性囊肿13例、潴留囊肿4例、先天性囊肿2例、浆液性囊性肿瘤(SCN)9例、黏液性囊性肿瘤(MCN)11例、导管内乳头状黏液性肿瘤(IPMN)7例、实性-假乳头状肿瘤(SPN)3例。49例患者中16例患者无症状,其余33例患者表现为腹痛、腹胀、恶心、呕吐、发热等。13例胰腺假性囊肿患者均有急、慢性胰腺炎或外伤病史,3例IPMN患者血清CA19-9升高。B超、CT、MRI/MRCP、EUS诊断胰腺囊性病变的准确率分别为24.5%、32.7%、61.1%、100%。49例患者均接受手术治疗,分别行内引流术、囊肿切除术、胰十二指肠切除术、胰体(尾)切除术以及节段性胰腺切除术。结论:胰腺囊性病变无特异性临床表现。CT、MRI/MRCP作为无创检查手段,应广泛用于囊性病变的诊断和评估,EUS可作为进一步检查手段。选择合理的手术方案是治疗胰腺囊性病变的关键。     

Endoscopic diagnosis of cystic lesions of the pancreas

Endoscopic methods are increasingly used in the diagnosis of cystic lesions of the pancreas. The two major endoscopic approaches are endoscopic ultrasonography (EUS) and transpapillary diagnosis. EUS‐guided fine‐needle aspiration cytology and EUS‐guided fine needle‐based confocal laser endomicroscopy have been used in the differential diagnosis of mucinous and non‐mucinous pancreatic cysts. EUS is the most sensitive modality for detecting mural nodules (MN) in intraductal papillary mucinous neoplasms (IPMN). Contrast‐enhanced harmonic EUS (CH‐EUS), as an add‐on to EUS, is useful for identifying and characterizing MN. Recent studies show that CH‐EUS has a sensitivity of 60–100% and a specificity of 75–92.9% for diagnosing malignant cysts. Intraductal ultrasonography and peroral pancreatoscopy are especially useful for detecting MN and IPMN. A recent meta‐analysis showed that cytological assessment of pancreatic juice using a transpapillary approach had a pooled sensitivity, specificity, and accuracy of 35.1%, 97.2%, and 92.9%, respectively, for diagnosing malignant IPMN. Further studies are warranted to determine the indications for each of these novel techniques in assessing cystic lesions of the pancreas.     

Endoscopic ultrasound-guided fine needle aspiration in diagnosis of cystic pancreatic lesions

Background and study aimspancreatic cysts are commonly found lesions and proper diagnosis is very important for planning further management. The study aims to evaluate the role of cyst fluid amylase and tumour markers as cancer antigen (CA 19-9) and carcinoembryonic antigen (CEA) in addition to mucin stain in diagnosing pancreatic cysts and differentiating malignant from benign lesions.Patients and methodsThis prospective study was conducted on 184 patients diagnosed to have pancreatic cystic lesions from January 2013 to January 2018. Fluid analysis for CA 19-9, CEA, amylase, mucin stain and cytopathology were done. We compared these data with the final diagnosis based on histopathology after surgical resection, positive cytopathology and long period of follow up of the patients for at least 18 months.ResultsThe highest AUC was that of cystic CEA with cut-off value of 160 ng/ml; it had a sensitivity of 60.4% and a specificity of 85%. The best cut-off value for cystic CA 19-9 was 1318 U/ml with a sensitivity of 64.1% and a specificity of 68.1%. The cut-off value of cyst amylase level was 5500 U/L, with 84.2% sensitivity and 37.1% specificity. The sensitivity of mucin stain in detecting mucinous cystic neoplasm was 85.45%, specificity was 86.05% with accuracy 85.87%.ConclusionCyst fluid analysis by investigating amylase, mucin, CA 19-9, CEA and EUS examination improves the diagnosis of different pancreatic cysts.     

Imaging Pancreatic Cysts with CT and MRI

CT and MRI are the imaging modalities of choice to guide the clinical management of incidentally discovered pancreatic cysts. Most of these lesions are mucinous cysts with varying degrees of malignant potential. This article reviews the CT and MRI findings that help differentiate a potentially aggressive lesion that requires EUS or surgery from a lesion of low malignant potential that is appropriate for imaging surveillance. The imaging-based societal guidelines for these cysts are reviewed.     

Role of endoscopic ultrasonography in pancreatic cystic neoplasms: Where do we stand and where will we go?

We increasingly encounter pancreatic cystic neoplasms (PCN) in clinical practice and the differential diagnoses vary widely from benign to malignant. There is no ‘one and only’ diagnostic procedure for PCN. Multiple modalities including computed tomography, magnetic resonance imaging, endoscopic retrograde cholangiopancreatography and endoscopic ultrasound (EUS) are widely used, but EUS has the advantage of anatomical proximity to the pancreas and upper gastrointestinal tract. In addition, EUS‐guided fine‐needle aspiration (EUS‐FNA) provides both cytological evaluation and cyst fluid analysis. Although the role of EUS‐FNA for PCN is established, the sensitivity of cytology is low and cyst fluid analysis is only useful for differentiation between mucinous and non‐mucinous cysts. Recently, novel through‐the‐needle imaging under EUS‐FNA, such as confocal laserendomicroscopy, is expected to attribute to a better diagnostic yield. Moreover, feasibility of cyst ablation has been reported and the role of EUS has expanded from diagnosis to treatment. However, clinical impact of cyst ablation in terms of safety, efficacy and cost‐effectiveness should be validated further. In summary, EUS and EUS‐guided intervention does and will play a central role in the management of PCN from surveillance to treatment, but many clinical questions remain unanswered, which warrants well‐designed prospective clinical trials.     

Precursor lesions of pancreatic cancer: molecular pathology and clinical implications.

BACKGROUND: Pancreatic cancer is a lethal disease, with near uniform 5-year mortality rates. The key to improving survival of pancreatic cancer rests upon early detection of this neoplasm at a resectable, and hence potentially curable, stage. METHODS: We review the current state of the literature vis-à-vis the three common precursor lesions of pancreatic adenocarcinoma: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. We also discuss two clinical scenarios of emerging importance, namely asymptomatic pancreatic cysts ('pancreatic incidentalomas') and the significance of precursor lesions in familial pancreatic cancer kindreds. RESULTS: Pancreatic intraepithelial neoplasias are the microscopic precursor lesions of pancreatic adenocarcinomas, while intraductal papillary mucinous neoplasms and mucinous cystic neoplasms are macroscopic, cystic precursor lesions. All three noninvasive entities demonstrate a multistep morphologic and genetic progression that culminates in frank invasive adenocarcinoma. Despite these commonalities, each precursor lesion harbors a unique repertoire of clinicopathologic and genetic characteristics that has an impact on natural history and prognosis of these lesions. Due to improvements in radiological techniques, asymptomatic pancreatic cysts are being increasingly discovered in the general population; intraductal papillary mucinous neoplasms and mucinous cystic neoplasms are the most common underlying histology in resected incidentalomas of the pancreas. Pancreatic asymptomatic cysts present an enormous challenge in terms of accurate diagnosis and management stratification. Incorporating molecular signatures of cystic precursor lesions into the diagnostic algorithm will likely become a standard of care for asymptomatic pancreatic cysts. High-risk individuals from familial pancreatic cancer kindreds are another group of individuals where knowledge of precursor lesions has had a therapeutic impact; sensitive imaging technologies have enabled the identification and subsequent resection of pancreatic cancer precursors in these high-risk individuals, preventing the progression to invasive cancer. CONCLUSIONS: Precursor lesions of pancreatic adenocarcinomas represent a unique opportunity for diagnosis and intervention for a malignancy with near uniform lethality. Further studies on these precursors will enable the development of rational early detection and therapeutic strategies in order to ameliorate pancreatic cancer survival.