Updates in diagnosis and management of pancreatic cysts

Incidental pancreatic cysts are commonly encountered with some cysts having malignant potential. The most common pancreatic cystic neoplasms include serous cystadenoma, mucinous cystic neoplasm and intraductal papillary mucinous neoplasm. Risk stratifying pancreatic cysts is important in deciding whether patients may benefit from endoscopic ultrasound (EUS) or surgical resection. Surgery should be reserved for patients with malignant cysts or cysts at high risk for developing malignancy as suggested by various risk features including solid mass, nodule and dilated main pancreatic duct. EUS may supplement magnetic resonance imaging findings for cysts that remain indeterminate or have concerning features on imaging. Various cyst fluid markers including carcinoembryonic antigen, glucose, amylase, cytology, and DNA markers help distinguish mucinous from nonmucinous cysts. This review will guide the practicing gastroenterologist in how to evaluate incidental pancreatic cysts and when to consider referral for EUS or surgery. For presumed low risk cysts, surveillance strategies will be discussed. Managing pancreatic cysts requires an individualized approach that is directed by the various guidelines.     

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA.

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.     

Molecular biomarkers have the potential to improve the diagnostic work-up of pancreatic cystic lesions

Pancreatic cysts are increasingly diagnosed due to the widespread use of cross-sectional imaging, and some of these lesions harbor malignant potential. Mucinous cystic neoplasms and intraductal papillary mucinous neoplasms are the major premalignant cystic neoplasms of the pancreas. A variety of diagnostic tools are used to predict the malignant potential of these cysts, but specificity and sensitivity are limited. Thus, many patients undergo unnecessary operations for benign cysts. Balancing the risks of watchful waiting with those of operative management is key in managing these lesions. During the last decade, genetic changes of pancreatic cysts have been examined extensively to estimate their malignant potential. In this review, we provide an overview of the latest molecular and genetic aspects of pancreatic cysts and how they may contribute to the differential diagnosis in patients with pancreatic cystic neoplasms.     

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.     

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.     

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.     

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.     

Pancreatic incidentalomas: Investigation and management

The incidence of pancreatic incidentalomas (PIs) detected in otherwise asymptomatic patients is growing with the increasing quality and use of advanced imaging techniques. PI can present as isolated main pancreatic duct dilation or as a solid or cystic lesion. Although historically thought to be relatively rare, PIs are rather common, particularly cystic lesions of the pancreas, which can be detected in up to 49% of the general population. With the poor prognosis of pancreatic cancer, PIs are an opportunity for prevention and early diagnosis, but when managed poorly, they can also lead to overtreatment and unnecessary morbidity. The management of PI should begin with a dedicated pancreas protocol computed tomography (CT) scan or magnetic resonance imaging (MRI) to accurately characterize duct size, lesion characteristics and establish an accurate baseline for subsequent follow up. Diagnosis and subsequent management depends on the extent of main duct dilation and solid versus cystic appearance. Solid lesions are highly concerning for malignancy. Cystic lesions can be further categorized as intraductal papillary mucinous neoplasms of the pancreas (IPMNs) or mucinous cystic neoplasms (MCNs), both of which harbour malignant potential, or as serous cystic neoplasms (SCNs) that are benign. In this paper, we summarize the major challenges related to PI and present pragmatic suggestions for management.     

Resektion zystischer Pankreastumoren

Cystic tumors of the pancreas are diagnosed increasingly more due to increasing life expectancy and the moderate use of modern radiological diagnostics. Intraductal papillary mucinous neoplasms of the pancreas (IPMN), mucinous cystic neoplasms (MCN), solid pseudopapillary neoplasms (SPN) and serous cystic neoplasms (SCN) represent over 90?% of all cystic neoplasms of the pancreas. Although serous cystic lesions have a low or even no potential for malignant transformation, they are mostly resected when symptomatic. In contrast, mucinous lesions have an increased malignant potential and should therefore be resected in almost all cases. While this is true for all cases of MCNs and SPNs this is controversial for all IPMNs as they show a wide spectrum of morphological variants. The IPMNs may arise in the main pancreatic duct, major side branches or in both (mixed type). Although all IPMNs are considered to be precursor lesions to pancreatic adenocarcinomas it is not clear what the time course of such potential neoplastic transformation might be and whether all lesions progress to malignant tumors. As no currently used diagnostic test can reliably differentiate between benign and malignant tumors, the majority of newly diagnosed IPMNs should undergo surgical resection. According to current treatment guidelines (Sendai criteria), asymptomatic side branch IPMNs of less than 3 cm in diameter without suspicious radiological features, such as nodules, thickness of the cystic wall or size progression can be treated conservatively without the need for surgical resection. Recently, this approach has become controversial due to a relevant number of IPMNs reported as Sendai negative that showed malignant transformation on final histological examination.     

Cytopathological Analysis of Cyst Fluid Enhances Diagnostic Accuracy of Mucinous Pancreatic Cystic Neoplasms

Widespread use of cross-sectional imaging and increasing age of the general population has increased the number of detected pancreatic cystic lesions. However, several pathological entities with a variety in malignant potential have to be discriminated to allow clinical decision making. Discrimination between mucinous pancreatic cystic neoplasms (PCNs) and nonmucinous pancreatic lesions is the primary step in the clinical work-up, as malignant transformation is mostly associated with mucinous PCN. We performed a retrospective analysis of all resected PCN in our tertiary center from 2000 to 2014, to evaluate preoperative diagnostic performance and the results of implementation of the consensus guidelines over time. This was followed by a prospective cohort study of patients with an undefined pancreatic cyst, where the added value of cytopathological mucin evaluation to carcinoembryonic antigen (CEA) in cyst fluid for the discrimination of mucinous PCN and nonmucinous cysts was investigated. Retrospective analysis showed 115 patients operated for a PCN, with a correct preoperative classification in 96.2% of the patients. High-grade dysplasia or invasive carcinoma was observed in only 32.3% of mucinous PCN. In our prospective cohort (n = 71), 57.7% of patients were classified as having a mucinous PCN. CEA ≥192 ng/mL had an accuracy of 63.4%, and cytopathological mucin evaluation an accuracy of 73.0%. Combining these 2 tests further improved diagnostic accuracy of a mucinous PCN to 76.8%. CEA level and mucin evaluation were not predictive of the degree of dysplasia. These findings show that adding cytopathology to cyst fluid biochemistry improves discrimination between mucinous PCN and nonmucinous cysts.     

Cyst fluid glucose: An alternative to carcinoembryonic antigen for pancreatic mucinous cysts

Pancreatic cystic lesions(PCLs) have been increasingly recognized in clinical practice. Although inflammatory cysts(pseudocysts) are the most common PCLs detected by cross-sectional imaging modalities in symptomatic patients in a setting of acute or chronic pancreatitis, incidental pancreatic cysts with no symptoms or history of pancreatitis are usually neoplastic cysts. For these lesions,it is imperative to identify mucinous cysts(intraductal papillary mucinous neoplasms and mucinous cystic neoplasms) due to the risk of their progression to malignancy. However, no single imaging modality alone is sufficient for a definitive diagnosis of all PCLs. The cyst fluid obtained by endoscopic ultrasound-guided fine needle aspiration provides additional information for the differential diagnosis of PCLs. Current recommendations suggest sending cyst fluid for cytology evaluation and measurement of carcinoembryonic antigen(CEA) levels. Unfortunately, the sensitivity of cytology is greatly limited, and cyst fluid CEA has demonstrated insufficient accuracy as a predictor of mucinous cysts. More recently, cyst fluid glucose has emerged as an alternative to CEA for distinguishing between mucinous and nonmucinous lesions. Herein, the clinical utility of cyst fluid glucose and CEA for the differential diagnosis of PCLs was evaluated.     

Cystic and solid lesions of the pancreas

More than 95% of malignant tumours of the pancreas are exocrine carcinomas. The exocrine carcinomas have to be distinguished from benign serous cystadenomas and tumours, the latter including mucinous cystic neoplasms, serous cysts, and solid pseudopapillary neoplasms. Cystic lesions have to be separated from pseudocysts, which are the most common cysts. Pseudocysts are due to extensive confluent autodigestive tissue necrosis caused by alcoholic, biliary, or traumatic acute pancreatitis. This review focuses on the classification of the different types of solid and cystic lesions based on histological criteria. The various imaging procedures are also discussed, along with their strengths and limitations.     

Beobachtung zystischer Pankreastumoren

At least 1 out of 40 adults without pre-existing pancreatic disease has a pancreatic cyst. Hence prophylactic resection of every cystic lesion is not a viable approach. However, in the total group of pancreatic cysts, mucinous cystic neoplasms are found in women aged 40–60 years and intraductal papillary mucinous neoplasms (IPNM) are more frequent in the group over 60 years old. Both entities bear a relevant potential of malignancy requiring a careful work-up including case history and qualified examinations with endoscopic ultrasound or magnetic resonance imaging. Using the diagnostic algorithm presented here the risk for an individual patient can be assessed. A resection of the cyst is recommended in cases of main duct IPNM, obstructive jaundice, cysts with solid parts and a lesion size of more than 3 cm. Even below this size increased attention is warranted in certain cases. For the majority of patients only one or a few control examinations are sufficient. After partial resection of the pancreas follow-up studies are necessary in cases of IPNM due to the risk of recurrence.     

Surgical Management of Pancreatic Cysts: A Shifting Paradigm Toward Selective Resection

Due to the widespread use of high-quality cross-sectional imaging, pancreatic cystic neoplasms are being diagnosed with increasing frequency. Clinicians are therefore asked to counsel a growing number of patients with pancreatic cysts diagnosed incidentally at an early, asymptomatic stage. Over the last two decades, accumulating knowledge on the biologic behavior of these neoplasms along with improved diagnostics through imaging and endoscopic cyst fluid analysis have allowed for a selective therapeutic approach toward these neoplasms. On one end of the management spectrum, observation is recommended for typically benign lesions (serous cystadenoma), and on the other end, upfront resection is recommended for likely malignant lesions (main duct IPMN, mucinous cystadenoma, solid pseudopapillary tumor, and cystic pancreatic neuroendocrine tumors). In between, management of premalignant lesions (branch duct IPMN) is dictated by the presence of high-risk features. In general, resection should be considered whenever the risk of malignancy is higher than the risk of the operation. This review aims to describe the evolution and current status of evidence guiding the selection of patients with pancreatic cystic neoplasms for surgical resection, along with a specific discussion on the type of resection required and expected outcomes.     

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.     

Precursors to pancreatic cancer

Infiltrating ductal adenocarcinoma of the pancreas is believed to arise from morphologically distinct noninvasive precursor lesions. These precursors include the intraductal papillary mucinous neoplasm, the mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia. Intraductal papillary mucinous neoplasms are grossly visible mucin-producing epithelial neoplasms that arise in the main pancreatic duct or one of its branches. The cysts of mucinous cystic neoplasms do not communicate with the major pancreatic ducts, and these neoplasms are characterized by a distinct ovarian-type stroma. Pancreatic intraepithelial neoplasia is a microscopic lesion. This article focuses on the clinical significance of these three important precursor lesions, with emphasis on their clinical manifestations, detection, and treatment.     

Cystic precursors to invasive pancreatic cancer

Improvements in the sensitivity and quality of cross-sectional imaging have led to increasing numbers of patients being diagnosed with cystic lesions of the pancreas. In parallel, clinical, radiological, pathological and molecular studies have improved the systems for classifying these cysts. Patients with asymptomatic serous cystic neoplasms can be managed conservatively with regular monitoring; however, the clinical management of patients with intraductal papillary mucinous neoplasms and mucinous cystic neoplasms is far more challenging, as it is difficult to determine whether these lesions will progress to malignancy. Fortunately, prospective studies have helped to establish that proposed clinical and radiological criteria (the Sendai guidelines) can be used to guide the care of patients with cystic lesions of the pancreas. Despite this progress in imaging and clinical guidelines, sensitive and specific tests have not yet been developed that can reliably predict the histology and biological properties of a cystic lesion. Such biomarkers are urgently needed, as noninvasive precursors of pancreatic cancer are curable, while the vast majority of invasive pancreatic adenocarcinomas are not.     

Presentation and management of pancreatic cystic neoplasms

Pancreatic cystic neoplasms are less frequent than other pancreatic tumors, but because of the wide availability and improvement of modern imaging methods, these neoplasms are being recognized with increasing frequency and it is often possible to be differentiated preoperatively not only from other cystic pancreatic disorders but also from one another. Most patients have no symptoms while clinical signs are not really useful in the clinical work up, and when they are present, they never help us to identify the type of pathology. Treatment differs with the diagnosis. Serous cystic neoplasms are uniformly benign and usually do not mandate resection unless this lesion is symptomatic. In contrast, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms have a premalignant or malignant tendency, and therefore should be managed aggressively by pancreatic resection; in the absence of invasive disease, prognosis is excellent after appropriate surgery, but the presence of invasive malignancy signifies a poor prognosis. Solid pseudopapillary neoplasms have nonaggressive behavior and their management is related to the extension of the disease. The purpose of this article is to review the types of pancreatic cystic neoplasms, their diagnosis, indications for surgical treatment, and outcome.     

Prevalence,Diagnosis and Management of Pancreatic Cystic Neoplasms: Current Status and Future Directions

Cystic neoplasms of the pancreas are found with increasing prevalence, especially in elderly asymptomatic individuals. Although the overall risk of malignancy is very low, the presence of these pancreatic cysts is associated with a large degree of anxiety and further medical investigation due to concerns about malignancy. This review discusses the different cystic neoplasms of the pancreas and reports diagnostic strategies based on clinical features and imaging data. Surgical and nonsurgical management of the most common cystic neoplasms, based on the recently revised Sendai guidelines, is also discussed, with special reference to intraductal papillary mucinous neoplasm (IPMN; particularly the branch duct variant), which is the lesion most frequently identified incidentally. IPMN pathology, its risk for development into pancreatic ductal adenocarcinoma, the pros and cons of current guidelines for management, and the potential role of endoscopic ultrasound in determining cancer risk are discussed. Finally, surgical treatment, strategies for surveillance of pancreatic cysts, and possible future directions are discussed.     

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.