Cyst fluid analysis in the differential diagnosis of pancreatic cystic lesions: a pooled analysis

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.

Posttransplant Characterization of Long-term Functional hESC-Derived Pancreatic Endoderm Grafts

The paucity of human donors limits broadened application of β-cell replacement therapy. Insulin-producing cells derived from human embryonic stem cells (hESCs) have recently been investigated clinically as a feasible surrogate to primary tissue. Herein, we examine the long-term efficacy of hESC-derived pancreatic endoderm cells (PECs) to maintain normoglycemia posttransplant and characterize the phenotype of the PEC grafts. Mice with chemically induced diabetes were transplanted with PECs into the subcutaneous device-less site. Transplant function was assessed through nonfasting blood glucose measurements, intraperitoneal glucose tolerance testing (IPGTT), and human C-peptide secretion for 517 days. Explanted grafts were assessed for ex vivo function and immunohistochemically. All PEC recipients (n = 8) maintained normoglycemia until graft retrieval. IPGTTs at 365 and 517 days posttransplant did not differ (P > 0.05), however, both demonstrated superior glucose clearance compared with nondiabetic and transplant controls (P < 0.001). Serum C-peptide levels demonstrated significant glucose responsiveness (fasted vs. stimulated) (P < 0.01). Small intragraft cysts were palpable in all mice, which resolved but recurred after aspiration. Cysts showed monomorphic neuroendocrine proliferation and lined by ductal epithelium. Explanted grafts demonstrated similar insulin secretory capacity as human islets and stained positively for endocrine cells. Our results demonstrate the ability of PECs to differentiate in vivo and restore glycemic control while confirming minimal proliferation and absence of neoplastic change within the grafts during the time evaluated.

Tissue acquisition in pancreatic cystic lesions

Despite the progress achieved by scientific research in recent years, pancreatic cystic lesions (PCLs) remain a challenging clinical problem. A significant percentage of benign PCLs are still wrongly sent to surgery, with all the related risks of a high number of surgery-related complications and mortality. Diagnosis of the type of PCL, and risk stratification for malignancy are essential for a correct management of these lesions. Several guidelines have identified some clinical and morphological aspects suggesting the need for more accurate exams. Endoscopic ultrasound fine needle aspiration (EUS-FNA) of cystic fluid for cytology is the advised method of tissue acquisition in several guidelines, and the most used technique around the world. However sensitivity and adequacy of this technique are limited by the low amount of cells dispersed in cystic fluid. Alternative techniques have been tested to target the cystic walls in an attempt to obtain microhistologic specimens in order to augment the probability of obtaining an adequate diagnostic sample. The aim of this review is to offer a critical overview of the existing literature on tissue acquisition in PCLs, and emphasize advantages and disadvantages of each technique, and unclear areas that need to be investigated with future research.

[Cystic lesions of the pancreas : Differential diagnostics and treatment]

Cystic space-occupying lesions of the pancreas represent incidental findings in most cases. As there is a potential risk of malignant transformation further evaluation of the lesions as well as a follow-up of these patients is usually recommended. Before this work-up is initiated the clinical situation of the patient as a whole and comorbidities, age and personal preferences have to be taken into account. So far there are no biomarkers that reliably predict the risk of malignant transformation. Imaging by magnetic resonance tomography (MRI) in combination with magnetic resonance cholangiopancreatography (MRCP) is more accurate than computed tomography to identify worrisome features. During follow-up, endoscopic ultrasound (EUS) can be used as complementary method to MRI/MRCP. Using contrast enhancement or endoscopic fine needle aspiration (EUS-FNA) may influence the therapeutic strategy in some patients. Whereas for some cystic pancreatic lesions consensus has been reached, varying recommendations exist for intraductal papillary mucinous neoplasms (IPMN). There is consensus that in main-duct as well as in mixed-type IPMN surgery is recommended. The management of branch-duct type IPMN, however, remains controversial. A multidisciplinary expert panel including gastroenterologists, visceral surgeons, radiologists and pathologists is essential to discuss all cases of patients with cystic pancreatic lesions and to guarantee an optimal, patient-centered treatment recommendation.

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.

Pancreatic Cysts: Sinister Findings or Incidentalomas?

Pancreatic cysts are common and are incidentally detected in up to 13.5% of individuals. Intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN) are precursors to pancreatic adenocarcinoma. Most will never develop into pancreatic cancer. Several types of pancreatic cysts have no malignant potential. Solid tumors can present as a pancreatic cysts. Guidelines recommend surveillance. Management includes differentiating IPMNs and MCNs from other types, identifying those at highest risk of harboring pancreatic cancer or high-grade dysplasia, and referral to a multidisciplinary group for evaluation and consideration of surgical resection.

Endoscopic ultrasound-guided through-the-needle microforceps biopsy in the evaluation of pancreatic cystic lesions: a multicenter study

Background and study aims  Accurate diagnosis and classification of pancreatic cysts (PCs) remains a challenge. The aims of this study were to: (1) evaluate the safety and technical success of a novel microforceps for EUS-guided through-the-needle biopsy (TTNB) of PCs; and (2) assess its diagnostic yield for mucinous PCs when compared to FNA cyst fluid analysis and cytology. Patients and methods  This was a multicenter retrospective analysis of 47 patients who underwent EUS-FNA and TTNB for PCs between January 2014 and June 2017. Technical success was defined as acquisition of a specimen adequate for cytologic or histological evaluation. Cyst fluid carcinoembryonic antigen (CEA) was used to initially categorize cysts as non-mucinous (CEA < 192 ng/mL) or mucinous (CEA ≥ 192 ng/mL). Final diagnosis was based on identifiable mucinous pancreatic cystic epithelium on cytology, microforceps histology and/or surgical histology when available. Results  Forty-seven patients with PCs (mean size 30.7 mm) were included. TTNB was successfully performed in 46 of 47 (97.9 %). Technical success was significantly lower with FNA (48.9 %) compared to TTNB (85.1 %) ( P  < .001). For cysts with insufficient amount of fluid for CEA (n = 19) or CEA < 192 ng/mL, the cumulative incremental diagnostic yield of a mucinous PC was significantly higher with TTNB vs. FNA (52.6 % vs 18.4 %; P  = .004). TTNB alone (34.4 %) diagnosed more mucinous PCs than either CEA ≥ 192 ng/mL alone (6.3 %) or when combined with FNA cytology (9.4 %). One episode of self-limited bleeding (2.1 %) and one of pancreatitis (2.1 %) occurred. Conclusions  EUS-TTNB is safe and effective for evaluating PCs. TTNB may help increase the diagnostic yield of mucinous PCs.

Mass Spectrometry-Based Comprehensive Analysis of Pancreatic Cyst Fluids

Pancreatic cyst fluids (PCFs) enriched in tumour-derived proteins are considered a potential source of new biomarkers. This study aimed to determine compositional and quantitative differences between the degradome and proteome of PCFs aspirated from different types of pancreatic cyst lesions (PCLs). 91 patients who underwent endoscopic ultrasound-fine needle aspiration under routine clinical diagnosis of PCLs were enrolled. Four cysts were malignant (CAs), and 87 were nonmalignant and consisted of 18 intraductal papillary mucinous neoplasms (IPMNs), 14 mucinous cystic neoplasms (MCNs), nine serous cystic neoplasms (SCNs), 29 pseudocysts (PCs), and 17 unclassified. Profiles of the <5 kDa fraction, the degradome, and the trypsin-digested proteome were analysed using an LTQ-Orbitrap Elite mass spectrometer coupled with a nanoACQUITY LC system. Qualitative analyses identified 796 and 366 proteins in degradome and proteome, respectively, and 689 (77%) and 285 (78%) of them were present in the Plasma Proteome Database. Gene Ontology analysis showed a significant overrepresentation of peptidases and peptidases inhibitors in both datasets. In the degradome fraction, quantitative values were obtained for 6996 peptides originating from 657 proteins. Of these, 2287 peptides were unique to a single type, and 515 peptides, derived from 126 proteins, were shared across cyst types. 32 peptides originating from 12 proteins had differential (adjusted p-value ≤0.05, FC ≥1.5) abundance in at least one of the five cysts types. In proteome, relative expression was measured for 330 proteins. Of them, 33 proteins had significantly (adjusted p-value ≤0.05, FC ≥1.5) altered abundance in at least one of the studied groups and 19 proteins appeared to be unique to a given cyst type. PCFs are dominated by blood proteins and proteolytic enzymes. Although differences in PCF peptide composition and abundance could aid classification of PCLs, the unpredictable inherent PCF proteolytic activity may limit the practical applications of PCF protein profiling.

Endoscopic ultrasound-through-the-needle biopsy in pancreatic cystic lesions: A multicenter study

BACKGROUND AND AIM

Tissue acquisition in pancreatic cystic lesions (PCL) is the ideal method for diagnosis and risk stratification for malignancy of these lesions. Direct sampling from the walls of PCL with different devices has shown better results than cytology from cystic fluid. We carried out a retrospective, multicenter study to evaluate the feasibility, safety, and diagnostic yield of a micro-forceps, specifically designed to be used through a 19-gauge needle after endoscopic ultrasonography (EUS)-guided puncture of PCL.

METHODS

We retrospectively collected data from patients who underwent EUS-through-the-needle biopsy (EUS-TTNB) in PCL at six referral centers.

RESULTS

The sampling procedure was carried out in 56 patients (mean age 57.5 ± 13.1 years, M:F 17:39), and was technically successful in all of them (100%; 95% confidence interval [CI], 94-100%). Adverse events occurred in 9/56 (16.1%; 95% CI, 8-28%) patients, with self-limited intracystic hemorrhage the most common (7/56, 12.5%; 95% CI, 5-24%). All adverse events were mild, and resolved without any specific intervention. Specimens were considered adequate for histological diagnosis in 47/56 (83.9%; 95% CI, 72-92%). In two of these patients, despite the histological adequacy, a diagnosis could not be reached. In two other cases, a specimen sufficient for a cytological diagnosis was obtained. Overall diagnostic yield by combining cytological and histological samples was 47/56 (83.9%; 95% CI, 72-92%).

CONCLUSION

EUS-TTNB with micro-forceps in PCL is feasible, safe, and has a high diagnostic yield. Future prospective studies are needed to better assess the clinical impact of EUS-TTNB on the management of PCL.

The Use of Biomarkers in the Risk Stratification of Cystic Neoplasms

Cyst fluid biomarkers may be used to identify pancreatic cyst subtypes. Biomarkers are selected based on their ability to accurately distinguish mucinous from nonmucinous cysts and to risk stratify cysts based on malignant potential. Biomarkers of interest include but are not limited to amylase, oncogenes, DNA analysis, and epigenetic markers. The introduction of next-generation sequencing and molecular panels has aided in improved diagnostic accuracy and risk stratification. This review presents the diagnostic performance of currently available biomarkers and proposes an algorithm to incorporate their use in the diagnosis of pancreatic cysts.

Management of Intraductal Papillary Mucinous Neoplasms: Controversies in Guidelines and Future Perspectives

Purpose of review

Management of intraductal papillary mucinous neoplasm (IPMN) is currently based on consensus, in the absence of evidence-based guidelines. In recent years, several consensus guidelines have been published, with distinct management strategies. In this review, we will discuss these discrepancies, in order to guide treating physicians in clinical management.

Recent findings

The detection rate of pancreatic cysts has increased substantially with the expanded use of high-quality imaging techniques to up to 45%. Of these cysts, 24–82% are IPMNs, which harbour a malignant potential. Timely detection of high-risk lesions is therefore of great importance. Surgical management is based on the presence of clinical and morphological high-risk features, yet the majority of resected specimens appear to be low risk.

Summary

International collaboration and incentive large-scale prospective registries of individuals undergoing cyst surveillance are needed to accumulate unbiased data and develop evidence-based guidelines. Additionally, development of non-invasive, accurate diagnostic tools (e.g. biomarkers) is needed to differentiate between neoplastic and non-neoplastic pancreatic cysts and detect malignant transformation at an early stage (i.e. high-grade dysplasia).

Pancreatic Cytology

The diagnostic approach to pancreaticobiliary disease requires a multidisciplinary team in which the cytopathologist plays a crucial role. Fine-needle aspiration, obtained by endoscopic ultrasound, is the diagnostic test of choice for pancreatic lesions. Preoperative clinical management depends on many factors, many of which rely on accurate cytologic assessment. Pancreaticobiliary cytology is wrought with diagnostic pitfalls. Clinical history, imaging studies, cytology samples, and ancillary tests, including immunohistochemistry, biochemical analysis, and genetic sequencing, are integral to forming a complete diagnosis and guiding optimal patient management. This article reviews clinical aspects and the diagnostic work-up of commonly encountered diagnostic entities within the field of pancreatic cytology.

Cyst Fluid Biomarkers - Diagnosis and Prediction of Malignancy for Cystic Lesions of the Pancreas

Pancreatic cysts are common, and are identified in 2-13% of individuals undergoing cross-sectional imaging. Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are pancreatic cysts which are precursors to pancreatic adenocarcinoma. Currently available tools are imperfect at differentiating IPMNs and MCNs from other, benign types of pancreatic cysts. The role of molecular markers in the evaluation of pancreatic cysts and the identification of cysts with high-grade dysplasia or invasive adenocarcinoma is reviewed.

Managing Incidental Pancreatic Cysts

PURPOSE OF REVIEW

The goal of this review is to critically analyze the current literature regarding the management of incidental pancreatic cysts. Given their increased rates of detection due to the frequent use of cross-sectional imaging, correctly identifying the subset of high risk lesions that are appropriate for surgical resection is critical. However, the existing consensus and societal guidelines discussed in this review lack high quality data to create evidence-based recommendations, making achieving this important aim challenging.

RECENT FINDINGS

Several recent studies have focused on the natural history of pancreatic cysts and defining the role of endoscopic ultrasound, which remains unclear. EUS-guided diagnostic tools include molecular analysis of obtained fluid; EUS-guided FNA, FNB, and intracystic forceps biopsy of the cyst wall; and confocal endomicroscopy. While their precise role in diagnosing pancreatic cystic neoplasms remains to be defined, they represent promising innovations that may play a future role in cyst assessment and management. Large, long-term, prospective studies of incidentally identified pancreatic cysts are essential to fully understand their natural history and potential for neoplastic progression. Given the absence of such data at present, an individualized patient approach is recommended.

The Role of Endoscopic Ultrasound in the Diagnosis of Cystic Lesions of the Pancreas

A precise diagnosis of the nature of pancreatic cystic neoplasm (PCN) is crucial since it determines the patients in need of rapid surgical resection as well as those who can be followed up, and, accordingly, the frequency and modalities of surveillance. Endoscopic ultrasound (EUS) and especially fine needle aspiration (FNA) are invasive methods, with specific adverse events occurring in 2.7-5%. Thus, they should only be used as a third-line tool in the absence of characteristic radiographic features on computed tomography (CT) scan and magnetic resonance imaging (MRI). The most difficult aspects of differential diagnosis are: intraductal papillary mucinous neoplasm (IPMN) versus chronic pancreatitis; unifocal IPMN versus serous cystic neoplasm (SCN); macrocystic SCN versus mucinous cystic neoplasm (MCN); cystic neuroendocrine tumors versus MCN; solid serous cystadenoma versus neuroendocrine tumors versus small solid pseudopapillary tumors; pseudocyst versus MCN; low-grade, high-grade, or invasive IPMN. When classical radiological and EUS features are not conclusive, EUS-FNA may be helpful by analyzing cytological, chemical, and/or molecular data. The addition of EUS-FNA to CT scan and MRI increased the overall accuracy for diagnosing PCN by 36 and 54%, respectively. Analysis of molecular markers in pancreatic cyst fluid might increase the limited accuracy of EUS-FNA by using cytology and chemical and/or tumor marker analysis alone. Current evidence suggests that contrast-enhanced EUS (CH-EUS) is highly accurate for distinguishing non-neoplastic cysts from neoplastic cysts. CH-EUS might also be useful for distinguishing mural epithelial nodules from mucinous clots. Needle-based confocal laser endomicroscopy (nCLE) images a target tissue at a subcellular level of resolution, providing real-time in-vivo optical biopsy. nCLE is feasible during EUS-FNA and allows in-vivo diagnosis of PCN with high accuracy. In conclusion, EUS is a third-line tool in the diagnosis of PCN. Clinical context as well as careful evaluation of CT scan and magnetic resonance cholangiopancreatography images by specialized radiologists are crucial in the diagnosis process. Nowadays it is inconceivable to skip these steps.

European evidence-based guidelines on pancreatic cystic neoplasms

Evidence-based guidelines on the management of pancreatic cystic neoplasms (PCN) are lacking. This guideline is a joint initiative of the European Study Group on Cystic Tumours of the Pancreas, United European Gastroenterology, European Pancreatic Club, European-African Hepato-Pancreato-Biliary Association, European Digestive Surgery, and the European Society of Gastrointestinal Endoscopy. It replaces the 2013 European consensus statement guidelines on PCN. European and non-European experts performed systematic reviews and used GRADE methodology to answer relevant clinical questions on nine topics (biomarkers, radiology, endoscopy, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystic neoplasm, rare cysts, (neo)adjuvant treatment, and pathology). Recommendations include conservative management, relative and absolute indications for surgery. A conservative approach is recommended for asymptomatic MCN and IPMN measuring <40 mm without an enhancing nodule. Relative indications for surgery in IPMN include a main pancreatic duct (MPD) diameter between 5 and 9.9 mm or a cyst diameter ≥40 mm. Absolute indications for surgery in IPMN, due to the high-risk of malignant transformation, include jaundice, an enhancing mural nodule >5 mm, and MPD diameter >10 mm. Lifelong follow-up of IPMN is recommended in patients who are fit for surgery. The European evidence-based guidelines on PCN aim to improve the diagnosis and management of PCN.

ACG Clinical Guideline: Diagnosis and Management of Pancreatic Cysts

Pancreatic cysts are very common with the majority incidentally identified. There are several types of pancreatic cysts; some types can contain cancer or have malignant potential, whereas others are benign. However, even the types of cysts with malignant potential rarely progress to cancer. At the present time, the only viable treatment for pancreatic cysts is surgical excision, which is associated with a high morbidity and occasional mortality. The small risk of malignant transformation, the high risks of surgical treatment, and the lack of high-quality prospective studies have led to contradictory recommendations for their immediate management and for their surveillance. This guideline will provide a practical approach to pancreatic cyst management and recommendations for cyst surveillance for the general gastroenterologist.

The Role of Next-Generation Sequencing in the Cytologic Diagnosis of Pancreatic Lesions

CONTEXT

- Integration of the analysis of genetic markers with endoscopic ultrasound-guided fine-needle aspiration and cytologic evaluation has increased the accuracy of the preoperative diagnosis of pancreatic lesions. The application of high-throughput gene panel analysis using next-generation sequencing platforms is now offering a great opportunity for further improvements.

OBJECTIVE

- To review the application of next-generation sequencing to the preoperative diagnosis of pancreatic lesions.

DATA SOURCES

- For data acquisition, a PubMed search using the terms next-generation sequencing, pancreas, pancreatic lesions, pancreatic tumors, and EUS-FNA was performed covering the years 2000-2017.

CONCLUSIONS

- KRAS remains the gene most widely studied for preoperative single-gene tests. Next-generation sequencing reliably allows analysis of multiple gene markers starting from limited amounts of DNA. The study of multigene panels has become a very attractive option for the management and preoperative risk stratification of patients with pancreatic cancer.

Cystic Lymphangioma: Are Triglycerides Always Measurable?

The presence of chylous fluid with high triglycerides levels on endoscopic ultrasound- (EUS-) guided fine needle aspiration (FNA) is very pathognomonic for the diagnosis of cystic lymphangiomas of the pancreas. In our case report the puncture of the pancreatic cyst showed a typical milky fluid though measurable triglyceride concentrations were absent in the laboratory. Two possible explanations were found. First of all grossly lipemic samples show a slower rate of color development than do clear serums which can produce a false negative result if the sample is insufficiently diluted. Secondly, high lipase levels can divide triglycerides in glycerol and fatty acids, making the concentration of triglycerides undetectable.

Pancreatic cyst fluid glucose: rapid, inexpensive, and accurate diagnosis of mucinous pancreatic cysts

BACKGROUND

The most widely accepted biochemical test for preoperative differentiation of mucinous from benign, nonmucinous pancreatic cysts is cyst fluid carcinoembryonic antigen. However, the diagnostic accuracy of carcinoembryonic antigen ranges from 70% to 86%. Based on previous work, we hypothesize that pancreatic cyst fluid glucose may be an attractive alternative to carcinoembryonic antigen.

METHODS

Pancreatic cyst fluid was collected during endoscopic or operative intervention. Diagnoses were pathologically confirmed. Glucose and carcinoembryonic antigen were measured using a patient glucometer and automated analyzer/enzyme-linked immunosorbent assay. Sensitivity, specificity, accuracy, and receiver operator characteristic analyses were performed.

RESULTS

Cyst fluid samples from 153 patients were evaluated (mucinous: 25 mucinous cystic neoplasms, 77 intraductal papillary mucinous neoplasms, 4 ductal adenocarcinomas; nonmucinous: 21 serous cystic neoplasms, 9 cystic neuroendocrine tumors, 14 pseudocysts, 3 solid pseudopapillary neoplasms). Median cyst fluid glucose was lower in mucinous versus nonmucinous cysts (19 vs 96 mg/dL; P < .0001). With a threshold of ≤ 50 mg/dL, cyst fluid glucose was 92% sensitive, 87% specific, and 90% accurate in diagnosing mucinous pancreatic cysts. In comparison, cyst fluid carcinoembryonic antigen with a threshold of >192 ng/mL was 58% sensitive, 96% specific, and 69% accurate. Area under the curve for glucose and CEA were similar at 0.91 and 0.92.

CONCLUSION

Cyst fluid glucose has significant advantages over carcinoembryonic antigen and should be considered for use as a routine diagnostic test for pancreatic mucinous cysts.

Analysis of Pancreatic Cyst Fluid

Pancreatic cysts are extremely common, and are identified in between 2% to 13% on abdominal imaging studies. Most pancreatic cysts are pseudocysts, serous cystic neoplasms, mucinous cystic neoplasms, or intraductal papillary mucinous neoplasms. The management of pancreatic cysts depends on whether a cyst is benign, has malignant potential, or harbors high-grade dysplasia or invasive carcinoma. The diagnosis of pancreatic cysts, and assessment of risk of malignant transformation, incorporates clinical history, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound, and fine-needle aspiration of cyst fluid. This article reviews the cyst fluid markers that are currently used, as well as promising markers under development.

Reviewing the Utility of EUS FNA to Advance Precision Medicine in Pancreatic Cancer

Advanced pancreatic cancer (PC) is an aggressive malignancy with few effective therapeutic options. While the evolution of precision medicine in recent decades has changed the treatment landscape in many cancers, at present no targeted therapies are used in the routine management of PC. Only a minority of patients with PC present with surgically resectable disease, and in the remainder obtaining high quality biopsy material for both diagnosis and molecular testing can prove challenging. Endoscopic ultrasound-guided fine needle aspiration (EUS FNA) is a widely used diagnostic procedure in PC, and allows tumour sampling in patients with both early and late stage disease. This review will provide an update on the role of EUS FNA as a diagnostic tool, as well as a source of genetic material which can be used both for molecular analysis and for the creation of valuable preclinical disease models. We will also consider relevant clinical applications of EUS FNA in the management of PC, and the path towards bringing precision medicine closer to the clinic in this challenging disease.

Molecular analysis of pancreatic cyst fluid changes clinical management

Background and Objectives

DNA molecular analysis has been suggested as a tool to evaluate pancreatic cysts. This study assesses whether the addition of DNA molecular analysis alters clinical management.

Methods

This is a retrospective review of 46 consecutive patients who underwent EUS-FNA of pancreatic cysts with DNA molecular analysis at two major academic institutions. Cases were presented to two pancreaticobiliary surgeons first without and then with DNA molecular analysis data. The primary outcome was the frequency with which clinical management was altered with the addition of DNA molecular analysis.

Results

Forty-six patients with a mean age of 62.0 (±13.4) years and mean cyst size of 3.2 (±2.3) cm were included in the study. Cyst carcinoembryonic antigen (CEA) was available in 30 patients and ranged from 0.4 to 15,927 ng/mL. DNA molecular analysis was described as benign in 23 (50%), statistically indolent in 13 (28%), statistically higher risk in 9 (20%), and indeterminate in 1 (2%). Surgeon #1 changed the management in 13/46 cases (28%) and surgeon #2 changed the management in 12/46 cases (26%) with the addition of DNA molecular analysis. When organized by CEA concentration, those with an intermediate CEA (45-800 ng/mL) or without a CEA concentration had a management changed more frequently (40%) compared to all others (P < 0.05).

Conclusions

The addition of DNA molecular analysis alters the clinical management of pancreatic cystic lesions most often when CEA levels are intermediate (45-800 ng/mL) or when no CEA concentration is available. Use of DNA molecular analysis can be considered in this cohort. Further study of molecular markers in pancreatic cystic lesions is recommended.

Pancreatic Cystic Lesions: New Endoscopic Trends in Diagnosis

The diagnosis of incidental pancreatic cystic lesions is increasing in the general population because of the routine use of cross-sectional imaging modalities. Not all cysts are neoplastic, and the majority of cystic neoplasms have a low overall likelihood of progression to malignancy. Current management is based on imaging and cyst fluid analysis, but we are not able to diagnose the specific type of cyst and its malignant potential in a significant number of patients. Better diagnostic tools are required to avoid unnecessary surgical resections that carry an important risk of morbidity and mortality. Herein we review current evidence concerning the use of new endoscopic modalities for the evaluation of pancreatic cystic lesions. We focus our discussion on the new cyst fluid markers, and the advancements on modalities such as confocal endomicroscopy, contrast-enhanced endoscopic ultrasound, and the use of Spyglass. We also discuss the use of new devices to improve the cellular yield from cyst fluid and to obtain cyst-wall tissue, namely the cytology brush, the fine needle biopsy, and forceps for cyst-wall biopsy.

Endoscopic Ultrasound Imaging for Diagnosing and Treating Pancreatic Cysts

Cystic pancreatic lesions are increasingly diagnosed owing to the abundant use of cross-sectional imaging. Given their malignant potential, true pancreatic cysts should be considered for resection or periodic follow-up. Cystic lesions of the pancreas (CLPs) require further evaluation and management. Therefore, it is important to establish a solid diagnosis at the time of detection. Endoscopic ultrasound examination is the imaging modality of choice. Fine needle aspiration provides fluid for cytologic, biochemical, and molecular assays to classify lesions and predict biological behavior. This review provides an overview of the diagnosis and management of various types of commonly encountered true CLPs.

Clinical Approach to Incidental Pancreatic Cystic Neoplasm in Outpatient Clinics

Cystic lesions of the pancreas are increasingly observed due to increased use of abdominal images. The malignant rate of pancreas cystic lesion varies widely between various types. Identification of malignant or high-risk lesions is important when determining the appropriate course of management. Using these image findings, including cyst size, presence of solid components, and pancreatic duct involvement, the 2012 International Association of Pancreatology (IAP) and the 2015 American Gastroenterological Association (AGA) guidelines provide a rationale in identifying higher risk patients requiring further workups using an endoscopic ultrasound (EUS). EUS with fine needle aspiration and cytology allows confirmation of the cyst type and determines the risk of malignancy. Small cysts with no suspicious features may undergo the regular imaging study for regular surveillance due to low risk for malignancy. In this review, the differences between the 2012 IAP and 2015 AGA guidelines are presented, In addition to possible recommendations for management and surveillance.

Tumor Markers in Pancreatic Cystic Fluids for Diagnosis of Malignant Cysts

Background and aim

Early diagnosis of premalignant or malignant pancreatic cysts is essential to improve prognosis. Sampling of pancreatic cyst fluid by fine-needle aspiration during endoscopic ultrasonography (EUS) enables cytopathological examination combined with biochemical analysis. This study aimed to provide an aid based on biological markers for the preoperative management of patients with pancreatic cysts.

Methods

Pancreatic fluids obtained by EUS-guided fine-needle aspiration from 115 patients with cystic lesions were assayed for amylase, lipase, carcinoembryonic antigen (CEA), CA 19-9 and CA 72-4. In addition, chromogranin A (CgA) and neuron-specific enolase (NSE) were measured in 28 fluid samples.

Results

ROC curve analysis of the different markers for diagnosis of mucinous cysts showed that CEA had the highest area under the curve (0.93, 95% CI 0.87-0.97), with a sensitivity and specificity of 89% and 93%, respectively, at the cutoff value of 317 μg/L. The CgA and NSE concentrations in 5 NET cysts (median values of 210 [63-492] and 68.5 [9-496] μg/L, respectively) were higher than in 23 other cysts (median values of 8 [7-828] and 2.7 [0.5-35.8] μg/L, respectively) (p = 0.0015 and p = 0.0045, respectively).

Conclusions

CEA is the best marker for identifying a cyst as mucinous. In case of low levels of CEA, our results suggest that CgA and NSE measurements may be helpful in the diagnosis of a neuroendocrine tumor and therefore deserve further investigation.

Revisions of international consensus Fukuoka guidelines for the management of IPMN of the pancreas

The management of intraductal papillary mucinous neoplasm (IPMN) continues to evolve. In particular, the indications for resection of branch duct IPMN have changed from early resection to more deliberate observation as proposed by the international consensus guidelines of 2006 and 2012. Another guideline proposed by the American Gastroenterological Association in 2015 restricted indications for surgery more stringently and recommended physicians to stop surveillance if no significant change had occurred in a pancreatic cyst after five years of surveillance, or if a patient underwent resection and a non-malignant IPMN was found. Whether or not it is safe to do so, as well as the method and interval of surveillance, has generated substantial debate. Based on a consensus symposium held during the meeting of the International Association of Pancreatology in Sendai, Japan, in 2016, the working group has revised the guidelines regarding prediction of invasive carcinoma and high-grade dysplasia, surveillance, and postoperative follow-up of IPMN. As the working group did not recognize the need for major revisions of the guidelines, we made only minor revisions and added most recent articles where appropriate. The present guidelines include updated information and recommendations based on our current understanding, and highlight issues that remain controversial or where further research is required.

Pancreatic Cysts - Part 2: Should We Be Less Cyst Centric?

The management of pancreatic cysts is a common problem faced by physicians and surgeons. Pancreatic cysts are important because some of them are mucin-producing cysts (MPCs), which may harbor or develop pancreatic ductal adenocarcinoma. Thus, accurate classification of pancreatic cysts and diagnosis of MPCs offer a potential for the prevention or early detection of pancreatic cancer. However, the diagnosis and management of asymptomatic pancreatic cysts are complicated by 2 factors. First, incidentally detected pancreatic cysts are often misdiagnosed as branch duct intraductal papillary mucinous neoplasms. Although most are MPCs, there are other types of cysts, such as serous cystadenomas, which are managed differently. Second, only a minority of MPCs will ultimately develop into invasive pancreatic ductal adenocarcinoma. Thus, on the one hand, pancreatic cysts offer a unique opportunity to identify precursors to pancreatic cancer and improve outcomes. On the other hand, misdiagnosis and overzealous testing or unnecessary surgery may lead to high cost and harm to patients. Several guidelines have been developed by various groups for the management of pancreatic cysts. In this article, we review the strengths and weaknesses of the American Gastroenterology Association guidelines, highlight key recommendations requiring further validation, and provide our balanced approach to diagnosing and managing pancreatic cysts.

Pancreatic Cyst Fluid Vascular Endothelial Growth Factor A and Carcinoembryonic Antigen: A Highly Accurate Test for the Diagnosis of Serous Cystic Neoplasm

Accurate differentiation of pancreatic cystic lesions is important for early detection and prevention of pancreatic cancer, as well as avoidance of unnecessary surgical intervention. Serous cystic neoplasms (SCNs) have no malignant potential, but can mimic the following premalignant mucinous cystic lesions: mucinous cystic neoplasm and intraductal papillary mucinous neoplasm (IPMN). We recently identified vascular endothelial growth factor (VEGF)-A as a novel pancreatic fluid biomarker for SCN. We hypothesize that combining cyst fluid CEA with VEGF-A will improve the diagnostic accuracy of VEGF-A. Pancreatic cyst/duct fluid was collected from consenting patients undergoing surgical cyst resection with corresponding pathologic diagnoses. Pancreatic fluid VEGF-A and CEA levels were detected by ELISA. One hundred and forty-nine patients with pancreatic cystic lesions met inclusion criteria. Pathologic diagnoses included pseudocyst (n = 14), SCN (n = 26), mucinous cystic neoplasm (n = 40), low-/moderate-grade IPMN (n = 34), high-grade IPMN (n = 20), invasive IPMN (n = 10), and solid pseudopapillary neoplasm (n = 5). Vascular endothelial growth factor A was significantly elevated in SCN cyst fluid compared with all other diagnoses (p < 0.001). With a threshold of >5,000 pg/mL, VEGF-A alone has 100% sensitivity and 83.7% specificity to distinguish SCNs from other cystic lesions. With a threshold of ≤10 ng/mL, CEA alone identifies SCN with 95.5% sensitivity and 81.5% specificity. Sensitivity and specificity of the VEGF-A/CEA combination are 95.5% and 100%, respectively. The c-statistic increased from 0.98 to 0.99 in the receiver operating characteristic analysis when CEA was added to VEGF-A alone. Although VEGF-A alone is a highly accurate test for SCN, the combination of VEGF-A with CEA approaches the gold standard for pathologic diagnosis, importantly avoiding false positives. Patients with a positive test indicating benign SCN can be spared a high-risk surgical pancreatic resection.

Endoscopic Management of Pancreatic Cysts

Management of pancreatic cystic lesions relies on patients' clinical presentation, imaging, and endoscopic ultrasound. Current research in basic science, radiology, and endoscopy is evolving and making progress in this condition which is relatively common in the general population. This review focuses on the recent endoscopic ultrasound approaches to the diagnosis of these pancreatic disorders.

Natural History of Pancreatic Cysts

Pancreatic cystic neoplasms are discovered with increasing frequency. Accurate knowledge of the natural history of cystic neoplasms is crucial to develop useful and cost-effective strategies for surveillance and surgical resection. To date, the natural history of cystic neoplasms is still incomplete due to lack of adequate diagnostic accuracy in the absence of surgical pathology. Nevertheless, current evidence points to risk factors for malignant transformation to help clinical management. New biomarkers that accurately distinguish cyst neoplasms and those most likely to progress to cancer would help clarify the natural history of cystic neoplasms.

Pancreatic Cysts: Controversies, Advances, Diagnoses, and Therapies

Pancreatic cysts are commonly found on cross-sectional imaging. The question arises in determining which lesions are premalignant or malignant and may require further testing, intervention, or follow-up. In pancreatic cysts without obvious malignancy on imaging, we approach them using the Four "S" Criteria. These are (1) symptoms that may be originating from the pancreatic cyst; (2) size of the cyst 2 cm or larger and/or main pancreatic duct greater than 5 mm; (3) survival of the patient, based on comorbidity index to determine surgical fitness; and then endoscopic ultrasound with fine needle aspiration (FNA) recommended to determine (4) solid component presence in the cyst, namely, nodule or thick walls, as well as to perform FNA to obtain cyst content. Current cyst fluid analysis options include use of cytology to determine presence of malignancy and carcinoembryonic antigen and fluid genetics to identify potentially premalignant lesions. The aims of this article are to explore current management guidelines for pancreatic cysts, present a comprehensive approach to pancreatic cysts, and explain the advantages and disadvantages of each option for evaluation of pancreatic cysts including endoscopic ultrasound with FNA with cyst fluid analysis using an evidence-based approach.

Sonographic and cyst fluid cytologic changes after EUS-guided pancreatic cyst ablation

BACKGROUND AND AIMS

The effect of EUS-guided pancreatic cyst ablation (PCA) on sonographic morphology and cyst fluid cytology is unknown. The aim of this study was to evaluate morphologic, cytologic, and change in cyst fluid DNA after PCA.

METHODS

In a prospective single-center study, consecutive patients with suspected benign 10- to 50-mm pancreatic cysts underwent baseline EUS-FNA and EUS-PCA followed 2 to 3 months later by repeat EUS, cyst fluid analysis, and possible repeat PCA. Surveillance imaging after ablation was performed at least annually and classified as complete response (CR), partial response, or persistent, with <5%, 5% to 25%, and 25% of the original cyst volume, respectively.

RESULTS

Thirty-six patients underwent EUS-PCA with ethanol alone (n = 8) or ethanol and paclitaxel (n = 28), and CR occurred in 19 patients (56%). After EUS-PCA, EUS showed an increase in wall diameter in 68%, decreased number of septations in 24%, increased debris in 24%, loss of mural nodule or novel calcification in 21%, and alteration of fluid viscosity in 48%. Follow-up cytology showed increased epithelial cellularity in 27%, loss or decreased cellular atypia in 15%, increased or appearance of macrophages in 24%, and inflammatory cells in 15%. Postablation DNA amount increased and quality decreased in 71% each. Between the CR and non-CR patients, there was no significant difference in frequency of sonographic or cytologic features. In the CR group, mean DNA quantity was significantly increased after ablation (P = .023) without a change in quality (P = .136).

CONCLUSIONS

EUS-PCA induces morphologic and cytologic changes of pancreatic cysts, none of which appears to predict overall imaging-defined response to ablation. (Clinical trial registration numbers: NCT00233038 and NCT01643460.).

Xanthogranulomatous pancreatitis: A review of the imaging characteristics of this rare and often misdiagnosed lesion of the pancreas

Xanthogranulomatous pancreatitis (XGP) is an extremely rare cause of a cystic pancreatic mass. The pathophysiology of this process is not entirely clear but likely results from a combination of duct obstruction, infection, and repeated hemorrhage. It is difficult to differentiate this inflammatory lesion from a cystic neoplasm and, therefore, in the majority of cases XGP is misdiagnosed as a neoplasm on preoperative imaging. In this report, we describe a case of XGP, the imaging characteristics of XGP, and a differential diagnosis for a cystic pancreatic lesion.

Management of Incidental Pancreatic Cysts: A White Paper of the ACR Incidental Findings Committee

The ACR Incidental Findings Committee (IFC) presents recommendations for managing pancreatic cysts that are incidentally detected on CT or MRI. These recommendations represent an update from the pancreatic component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Pancreas Subcommittee-which included abdominal radiologists, a gastroenterologist, and a pancreatic surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion, and were finalized by informal iterative consensus. Algorithm branches successively categorize pancreatic cysts based on patient characteristics and imaging features. They terminate with an ascertainment of benignity and/or indolence (sufficient to discontinue follow-up), or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected pancreatic cysts.

Endoscopic ultrasonography evaluation for pancreatic cysts: Necessity or overkill?

Incidental pancreatic cysts have become gradually more recognized in clinical practice as a result of increased use of transabdominal ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). These lesions consist of inflammatory cysts (pseudocysts) and pancreatic cystic neoplasms (PCN) which have been classified as benign, premalignant and malignant. The diagnosis and management strategy of incidentally discovered pancreatic cysts can be challenging as the majority of them are PCN and CT or MRI alone may not be sufficient to provide an accurate diagnosis. Endoscopic ultrasound (EUS)-guided fine-needle aspiration provides a method to obtain cyst fluid for analysis and the recently developed EUS-based technology including contrast-enhanced ultrasound, cystoscopy and needle-based confocal laser endomicroscopy allows endosonographers to gain additional useful information. The current data suggest that EUS evaluation of pancreatic cysts offers some benefits especially in cases of inconclusive CT or MRI.

Endoscopic ultrasonography-guided tissue acquisition: How to achieve excellence

Endoscopic ultrasound (EUS)-guided tissue acquisition is a basic forte of an endosonographer. The multiple skills required to accomplish successful results include not only the puncture itself, but also proper lesion identification, correct puncture sequence, collaboration with the pathologist onsite or remotely, proper handling of the specimens, choosing one or more of cytology, cell-block, and/or tissue core preparation and, last, deciding the immunohistochemistry (IHC) panels and ancillary tests which may be needed for the current case. Error in any of these decisions may lead to incomplete or inconclusive information from the procedure, even if the aspirate is 'adequate.' In the present review, we will describe the technical aspects of EUS-guided tissue acquisition, current needles available and how to choose between them, and how to appropriately handle the specimen. We will also discuss the optimal approach to common targets including lymph nodes, pancreatic masses, pancreatic cysts, and subepithelial lesions.

Pancreatic juice cytology with immunohistochemistry to detect malignancy and histologic subtypes in patients with branch duct type intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND AND AIMS

The aim of this study was to elucidate the efficacy of pancreatic juice cytology with the cell-block method (CB-PJC) for the determination of surgery in patients with branch duct intraductal papillary mucinous neoplasm (BD-IPMN).

METHODS

In 138 patients with BD-IPMN from whom pancreatic juice was collected under ERCP for CB-PJC, we retrospectively evaluated the following: (1) the rate of successfully evaluated CB-PJC; (2) the ability of CB-PJC to diagnose malignancy and to identify pathologic subtypes in resected BD-IPMNs; (3) the rate of development into invasive cancer and progression of BD-IPMNs in patients with BD-IPMNs diagnosed as benignancy by CB-PJC; and (4) post-ERCP adverse events.

RESULTS

(1) The success rate of CB-PJC was 89.9%. (2) The sensitivity and specificity of CB-PJC for preoperative diagnosis of malignancy were 50% and 100%, respectively, with only hematoxylin and eosin staining, whereas they were 79% and 100%, respectively, by adding immunohistologic staining. The agreement rate of the preoperative subtypes by CB-PJC with the subtypes of resected specimens was 93%. (3) The onset of invasive cancer was not detected at all on imaging studies, whereas the progression of IPMN was detected in 14 patients. Multivariate analysis revealed the risk factor of progression to be non-gastric type. The cumulative 5-year progression rate in this group was 89%. (4) Post-ERCP pancreatitis developed in 13 patients (7.7%).

CONCLUSIONS

The diagnostic efficacy of preoperative CB-PJC for malignant BD-IPMN was excellent. The results may suggest the feasibility of applying preoperative subtyping by CB-PJC for decisions as to whether surgery is indicated.

Differentiation of Pancreatic Cyst Types by Analysis of Rheological Behavior of Pancreatic Cyst Fluid

Differentiation between mucinous and non-mucinous pancreatic cysts is exceedingly important and challenging, particularly as the former bears malignant transformation potential. Pancreatic cyst fluid (PCF)-based diagnostics, including analyses of biochemical markers, as well as cytology, has shown inadequate accuracy. Herein, a preliminary single-center study of 22 PCF samples, collected by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), assessed the rheological behavior of PCF and its correlation with lesion type. The dependence of PCF shear viscosity on shear rate was found to follow a power law and could be fitted using Ostwald-de Waele model. Three types of flow curves were identified, where two types correlated with non-mucinous cysts, differing by their power law exponent, and the third type corresponding to mucinous cysts. Viscosity measured at a high shear rate was shown to serve as an accurate and independent marker distinguishing between mucinous and non-mucinous cysts, with an optimal cutoff value of ηc = 1.3 cP The accuracy of this novel technique proved superior to string-sign, cytology, carcinoembryonic antigen, and amylase assessments. Moreover, the combined predictive value of ηc and patient age provided for sensitivity and specificity of 100% and 95.5%, respectively. This simple and rapid diagnostic tool can be immediately implemented after EUS-FNA sampling.

The Combination of Cyst Fluid Carcinoembryonic Antigen, Cytology and Viscosity Increases the Diagnostic Accuracy of Mucinous Pancreatic Cysts

BACKGROUND/AIMS

The objective of this study was to investigate the value of cyst fluid carcinoembryonic antigen (CEA) in combination with cytology and viscosity for the differential diagnosis of pancreatic cysts.

METHODS

We retrospectively reviewed our data for patients who underwent endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) and cyst fluid analysis. We investigated the sensitivity, specificity and accuracy of the combination of cyst fluid CEA, cytology and viscosity testing.

RESULTS

A total of 177 patients underwent EUS-FNA and cyst fluid analysis. Of these, 48 subjects were histologically and clinically confirmed to have pancreatic cysts and were therefore included in the analysis. Receiver operator curve analysis demonstrated that the optimal cutoff value of cyst fluid CEA for differentiating mucinous versus nonmucinous cystic lesions was 48.6 ng/mL. The accuracy of cyst fluid CEA (39/48, 81.3%) was greater than the accuracy of cytology (23/45, 51.1%) or the string sign (33/47, 70.2%). Cyst fluid CEA in combination with cytology and string sign assessment exhibited the highest accuracy (45/48, 93.8%).

CONCLUSIONS

Cyst fluid CEA was the most useful single test for identifying mucinous pancreatic cysts. The addition of cytology and string sign assessment to cyst fluid CEA increased the overall accuracy for the diagnosis of mucinous pancreatic cysts.

Light scattering spectroscopy identifies the malignant potential of pancreatic cysts during endoscopy

Pancreatic cancers are usually detected at an advanced stage and have poor prognosis. About one fifth of these arise from pancreatic cystic lesions. Yet not all lesions are precancerous, and imaging tools lack adequate accuracy for distinguishing precancerous from benign cysts. Therefore, decisions on surgical resection usually rely on endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Unfortunately, cyst fluid often contains few cells, and fluid chemical analysis lacks accuracy, resulting in dire consequences, including unnecessary pancreatic surgery for benign cysts and the development of cancer. Here, we report an optical spectroscopic technique, based on a spatial gating fibre-optic probe, that predicts the malignant potential of pancreatic cystic lesions during routine diagnostic EUS-FNA procedures. In a double-blind prospective study in 25 patients, with 14 cysts measured in vivo and 13 postoperatively, the technique achieved an overall accuracy of 95%, with a 95%confidence interval of 78-99%, in cysts with definitive diagnosis.

Pancreatic endometrial cyst mimics mucinous cystic neoplasm of the pancreas

Pancreatic cysts include a variety of benign, premalignant, and malignant lesions. Endometrial cysts in the pancreas are exceedingly rare lesions that are difficult to diagnose pre-operatively. This report describes the findings in a 43-year-old patient with a recent episode of acute pancreatitis who presented with a large cyst in the tail of the pancreas. Imaging demonstrated a loculated pancreatic cyst, and cyst fluid aspiration revealed an elevated amylase and carcinoembryonic antigen. The patient experienced an interval worsening of abdominal pain, fatigue, diarrhea, and a 15-pound weight loss 3 mo after the initial episode of pancreatitis. With concern for a possible pre-malignant lesion, the patient underwent a laparoscopic distal pancreatectomy with splenectomy, which revealed a 16 cm × 12 cm × 4 cm lesion. Final histopathology was consistent with an intra-pancreatic endometrial cyst. Here we discuss the overlapping imaging and laboratory features of pancreatic endometrial cysts and mucinous cystic neoplasms of the pancreas.