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.     

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.     

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.     

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.     

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.     

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.     

Lymphoepithelial cysts of the pancreas: The use of endoscopic ultrasound-guided fine-needle aspiration in diagnosis

Lymphoepithelial cysts (LECs) are rare non-neoplastic lesions that can appear as a complex cyst or a mass in the pancreas. Cytology from endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) can be helpful in making a diagnosis with the aim of avoiding unnecessary surgical resection. A case involving a 51-year-old woman with lower abdominal pain who was found to have a multiloculated cystic lesion at the junction of the pancreatic body and tail is described. Cytology from EUS-FNA was consistent with a pancreatic LEC. The lesion was managed conservatively and follow-up imaging of the cyst over the following two years was unchanged. The patient remains clinically well. Cytology from EUS-FNA can help distinguish LECs from cystic neoplasms, thus preventing radical surgical resection of this benign pancreatic cyst.     

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.     

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.     

Nature and management of pancreatic mucinous cystic neoplasm (MCN): A systematic review of the literature

BackgroundThe current management of pancreatic mucinous cystic neoplasms (MCN) is defined by the consensus European, International Association of Pancreatology and American College of Gastroenterology guidelines. However, the criterion for surgical resection remains uncertain and differs between these guidelines. Therefore through this systematic review of the existing literature we aimed to better define the natural history and prognosis of these lesions, in order to clarify recommendations for future management.MethodsA systematic literature search was performed (PubMed, EMBASE, Cochrane Library) for studies published in the English language between 1970 and 2015.ResultsMCNs occur almost exclusively in women (female:male 20:1) and are mainly located in the pancreatic body or tail (93–95%). They are usually found incidentally at the age of 40–60 years. Cross-sectional imaging and endoscopic ultrasound are the most frequently used diagnostic tools, but often it is impossible to differentiate MCNs from branch duct intraductal papillary mucinous neoplasms (BD-IPMN) or oligocystic serous adenomas pre-operatively. In resected MCNs, 0–34% are malignant, but in those less than 4 cm only 0.03% were associated with invasive adenocarcinoma. No surgically resected benign MCNs were associated with a synchronous lesion or recurrence; therefore further follow-up is not required after resection. Five-year survival after surgical resection of a malignant MCN is approximately 60%.ConclusionsCompared to other pancreatic tumors, MCNs have a low aggressive behavior, with exceptionally low rates of malignant transformation when less than 4 cm in size, are asymptomatic and lack worrisome features on pre-operative imaging. This differs significantly from the natural history of small BD-IPMNs, supporting the need to differentiate mucinous cyst subtypes pre-operatively, where possible. The findings support the recommendations from the recent European Consensus Guidelines, for the more conservative management of MCNs.     

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.     

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.     

Comparison of endoscopic ultrasound and computed tomography in the assessment of pancreatic cyst size using pathology as the gold standard

Background/objectivesAccurate assessment of whether a cyst is greater than 3 cm is an essential component when considering resection especially for mucinous lesions. The most accurate method of assessing cyst size is uncertain with many patients undergoing several complimentary imaging modalities. This study aimed to compare the accuracy of endoscopic ultrasound (EUS) with CT scanning in assessing pancreatic cyst size compared to histology.MethodsPatients referred for EUS of a pancreatic cystic lesion from April 2003 to August 2011. Patient age and gender, lesion size and site were recorded and compared using cyst size at histology compared to EUS and CT recorded within 3 months of surgery. Subgroup analysis was performed with respect to cyst site and proven mucinous lesions.Results357 patients were included of which 70 (mean age 60.6 years, 24 males) had undergone surgical resection. The resected cysts were located 30/17/23 in the head/body/tail of the pancreas. Median size at histology was 32 mm compared to 35 mm at EUS (p = 0.47) and 35 mm at CT (p = 0.52). For mucinous lesions alone, median size at histology was 32 mm compared to 33 mm at EUS (p = 0.46) and 35 mm at CT (p = 0.39). EUS and CT had comparable sensitivity, specificity, negative predictive value, positive predictive value and accuracy for all cyst types and locations.ConclusionsCT and EUS measurements are not significantly different to pathological size following resection of pancreatic cystic lesions. CT and EUS are interchangeable investigations for determining cyst size pre-operatively although EUS has the additional advantage of fluid sampling.     

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.     

Patient- and Cyst-Related Factors for Improved Prediction of Malignancy within Cystic Lesions of the Pancreas

Background and Aims: Early diagnosis of cancer in pancreatic cysts is important for timely referral to surgery. The aim of this study was to develop a predictive model for pancreatic cyst malignancy to improve patient selection for surgical resection. Methods: We performed retrospective analyses of endoscopic ultrasound (EUS) and pathology databases identifying pancreatic cysts with available final pathological diagnoses. Main-duct intraductal papillary mucinous neoplasms (IPMNs) were excluded due to the clear indication for surgery. Patient demographics and symptoms, cyst morphology, and cyst fluid characteristics were studied as candidate riskfactors for malignancy. Results: 270 patients with pancreatic cysts were identified and analyzed (41% men, mean age 61.8 years). Final pathological diagnoses were branch-duct IPMN (n = 118, 50% malignant), serous cystadenoma (n = 71), pseudocyst (n = 37), mucinous cyst adenoma/adenocarcinoma (n = 36), islet cell tumor (n = 4), simple cyst (n = 3), and ductal adenocarcinoma with cystic degeneration (n = 1). Optimal cut-off points for surgical resection were cyst fluid carcinoembryonic antigen (CEA) ≥3,594 ng/ml, age >50, and cyst size >1.5 cm. Cyst malignancy was independently associated with white race (OR = 4.1, p = 0.002), weight loss (OR = 3.9, p = 0.001), cyst size >1.5 cm (OR = 2.4, p = 0.012), and high CEA >3,594 (OR = 5.3, p = 0.04). In white patients >50 years old presenting with weight loss and cyst size >1.5 cm, the likelihood of malignancy was nearly sixfold greater than in those patients who had none of these factors (OR = 5.8,95% CI = 2.1-16.1, p = 0.004). Conclusions: Riskfactors other than cyst size are important for determination of malignancy in pancreatic cysts. Exceptionally high cyst fluid CEA levels and certain patient-related factors may help to better predict cyst malignancy and the need for surgical treatment.     

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.     

Clinicopathologic review of 41 cases of pancreatic mucinous cystic neoplasms]

BACKGROUND/AIMS: Intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms are included in mucin-producing pancreatic tumors. The reports about IPMN are not uncommon but those about the mucinous cystic neoplasms are relatively few. The aims of this study were to define the natural history of resected mucinous cystic neoplasms of the pancreas and to identify the findings which suggest malignancy. METHODS: The authors retrospectively evaluated the clinical outcomes of 41 patients with mucinous cystic neoplasms who were surgically resected at Asan Medical Center between 1995 and 2004. RESULTS: Women (n=33) were more frequently affected than men (n=8). Thirty three patients (80.6%) had adenoma, 1 (2.4%) borderline malignancy, 1 (2.4%) carcinoma in situ, and 6 (14.6%) invasive mucinous cystadenocarcinoma. The most frequent symptom was abdominal pain (39%). About half of the enrolled patients were asymptomatic. Unilocular type (79%) was more frequent than the multilocular type (21%) on gross morphology. The tumor size of invasive mucinous cystic neopolasms was larger than that of non-invasive mucinous cystic neoplalsms (p=0.01). Abdominal pain was more frequent in invasive mucinous cystic neoplasms (p=0.026). On gross morphology, mural nodules were detected in 4 of 6 patients with invasive mucinous cystic neoplasms. However, they were not detected in any patients with non-invasive mucinous cystic neoplasms. Recurrence developed in none of the 35 patients with non-invasive mucinous cystic neoplasms, however 2 of the 6 patients with invasive mucinous cystic neoplasms died within 5 years. CONCLUSIONS: Clinical predictors of invasive mucinous cystic neoplasms are suggested to be tumor size and abdominal pain. The prognosis of the non-invasive mucinous cystic neoplasms is excellent when curative resection is performed.