Serous cystic neoplasms of the pancreas: clinicopathologic and molecular characteristics

Misdiagnosis of pancreatic intraductal papillary mucinous neoplasms and the challenge of mimicking lesions: imaging diagnosis and differentiation strategies

The rising prevalence of pancreatic cystic lesions (PCLs), particularly intraductal papillary neoplasms (IPMNs), has been attributed to increased utilization of advanced imaging techniques. Incidental detection of PCLs is frequent in abdominal CT and MRI scans, with IPMNs representing a significant portion of these lesions. Surveillance of IPMNs is recommended due to their malignant potential; however, their overlapping imaging features with benign entities can lead to misdiagnosis, overtreatment, and overutilization of healthcare resources. This paper aims to highlight and differentiate lesions often mistaken for IPMNs, providing insight into their imaging characteristics, diagnostic challenges, and distinctive features while highlighting the incidence of wrong diagnosis for these lesions. These lesions include serous cystadenomas, cystic pancreatic neuroendocrine tumors, mucinous cystic neoplasms, lymphoepithelial cysts, duodenal diverticula, pancreatic schwannomas, chronic pancreatitis, retention cysts, intrapancreatic accessory spleens, pancreatic lipomas, choledochal cysts, and others. Utilizing various imaging modalities, including contrast-enhanced CT, MRI, and EUS, alongside histological and molecular analyses, can aid in accurate diagnosis and appropriate management. Understanding these mimicry scenarios is crucial to avoid unnecessary surveillance, interventions, and the burden they place on both patients and healthcare systems. Improved recognition of these lesions can lead to better patient outcomes and resource allocation.

Radiomics for Differentiating Pancreatic Mucinous Cystic Neoplasm from Serous Cystic Neoplasm: Systematic Review and Meta-Analysis

BACKGROUND

As pancreatic cystic neoplasms (PCN) differ in current standard of care, and these treatments can affect quality of life to varying degrees, a definitive preoperative diagnosis must be reliable. Current diagnostic approaches, specifically traditional cross-sectional imaging techniques, face certain limitations. But radiomics has been shown to have high diagnostic accuracy across a range of diseases. Objective to conduct a comprehensive review of the literature on the use of radiomics to differentiate Mucinous Cystic Neoplasm (MCN) from Serous Cystic Neoplasm (SCN).

METHODS

This study was comprehensively searched in Pubmed, Scopus and Web of Science databases for meta-analysis of studies that used radiomics to distinguish MCN from SCN. Risk of bias was assessed using the diagnostic accuracy study quality assessment method and combined with sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic (SROC)curve analysis.

RESULTS

A total of 884 patients from 8 studies were included in this analysis, including 365 MCN and 519 SCN. The Meta-analysis found that radiomics identified MCN and SCN with high sensitivity and specificity, with combined sensitivity and specificity of 0.84(0.82-0.87) and 0.82(0.79-0.84). The positive likelihood ratio (PLR) and the negative likelihood ratio (NLR) are 5.61(3.72, 8.47) and 0.14(0.09-0.26). In addition, the area under the SROC curve (AUC) was drawn at 0.93. No significant risk of publication bias was detected through the funnel plot analysis. The performances of feature extraction from the volume of interest (VOI) or Using AI classifier in the radiomics models were superior to those of protocols employing region of interest (ROI) or absence of AI classifier.

CONCLUSION

This meta-analysis demonstrates that radiomics exhibits high sensitivity and specificity in distinguishing between MCN and SCN, and has the potential to become a reliable diagnostic tool for their identification.

Pancreatic Serous Neoplasm and Metastatic Clear Cell Renal Cell Carcinoma: Diagnostic Pitfalls Resolvable by a Panel of Immunohistochemical Stains to Include PAX8 and CK7 But Not CAIX

Pancreatic serous neoplasms can morphologically resemble metastatic clear cell renal cell carcinoma (ccRCC) and may present a diagnostic dilemma, particularly if the solid variant is in small biopsy specimens and/or in patients with von Hippel Lindau (VHL) syndrome. We investigate the utility of immunohistochemical staining in this differential diagnosis by performing head-to-head comparisons of commonly used immunohistochemical markers for these 2 tumor types. We examined 16 pancreatic serous neoplasms and 24 ccRCCs (12 metastatic to pancreas and 12 primaries in patients with VHL). All pancreatic serous neoplasms stained positive for CK7, and most were positive for CAIX (15/16) and GLUT1 (15/16), variable for alpha-inhibin and vimentin (each 8/16 weak/focal; and 7/16 and 8/16, respectively, positive), and weak/focal for synaptophysin (14/16). All pancreatic serous neoplasms were negative for PAX8 and Periodic acid-Schiff without diastase. In contrast, ccRCC, both metastatic and in VHL patients, were mostly positive for PAX8 (18/24; 6/24 were weak/focal), negative for CK7 (15/24; 8/24 were weak/focal, one case diffuse positive), and negative for alpha-inhibin (100%) and synaptophysin (22/24). Like pancreatic serous neoplasms, all ccRCC showed weak/focal or positive staining for GLUT1, CAIX, and vimentin, and were negative for PAS-D. In conclusion, CK7 and PAX8 are the most useful stains in distinguishing between pancreatic serous neoplasm and ccRCC; however, weak/focal CK7 or PAX8 staining can be seen in a minority of ccRCC, thereby presenting a diagnostic pitfall. Alpha-inhibin was at least weak/focal in most pancreatic serous neoplasms and negative in all ccRCC and may be useful as an adjunct stain in difficult cases.

Imaging of pancreatic serous cystadenoma and common imitators

Pancreatic cystic neoplasms are lesions comprised of cystic components that show different biological behaviors, epidemiology, clinical manifestations, imaging features, and malignant potential and management. Benign cystic neoplasms include serous cystic neoplasms (SCAs). Other pancreatic cystic lesions have malignant potential, such as intraductal papillary mucinous neoplasms and mucinous cystic neoplasms. SCAs can be divided into microcystic (classic appearance), honeycomb, oligocystic/macrocystic, and solid patterns based on imaging appearance. They are usually solitary but may be multiple in von Hippel-Lindau disease, which may depict disseminated involvement. The variable appearances of SCAs can mimic other types of pancreatic cystic lesions, and cross-sectional imaging plays an important role in their differential diagnosis. Endoscopic ultrasonography has helped in improving diagnostic accuracy of pancreatic cystic lesions by guiding tissue sampling (biopsy) or cyst fluid analysis. Immunohistochemistry and newer techniques such as radiomics have shown improved performance for preoperatively discriminating SCAs and their mimickers.

Artificial Intelligence in Pancreatic Image Analysis: A Review

Pancreatic cancer is a highly lethal disease with a poor prognosis. Its early diagnosis and accurate treatment mainly rely on medical imaging, so accurate medical image analysis is especially vital for pancreatic cancer patients. However, medical image analysis of pancreatic cancer is facing challenges due to ambiguous symptoms, high misdiagnosis rates, and significant financial costs. Artificial intelligence (AI) offers a promising solution by relieving medical personnel's workload, improving clinical decision-making, and reducing patient costs. This study focuses on AI applications such as segmentation, classification, object detection, and prognosis prediction across five types of medical imaging: CT, MRI, EUS, PET, and pathological images, as well as integrating these imaging modalities to boost diagnostic accuracy and treatment efficiency. In addition, this study discusses current hot topics and future directions aimed at overcoming the challenges in AI-enabled automated pancreatic cancer diagnosis algorithms.

Improving diagnostic yield of pancreatic serous cystadenoma with cyst fluid ancillary testing, adjunct immunohistochemistry, and additional fine-needle biopsy sampling

BACKGROUND

Fine-needle aspiration (FNA) diagnosis of pancreatic serous cystadenoma (SCA) remains challenging. This retrospective study aimed to evaluate the roles of cyst fluid ancillary testing and combined fine-needle biopsy (FNB) in improving the diagnostic yield.

METHODS

The authors retrospectively reviewed cytology cases that were histologically confirmed SCAs. Clinical features and FNA cyst fluid biochemical and molecular analysis results along FNB findings were reviewed.

RESULTS

The study cohort included 31 cases from 13 male and 18 female patients with a mean age of 65. The original cytologic diagnoses were nondiagnostic (n = 6, 19%), negative for malignant cells/cyst contents (n = 7, 23%), atypical cells (n = 3, 10%), nonmucinous cyst (n = 11, 35%), and serous cystadenoma (n = 4, 13%). Cyst fluid carcinoembryonic antigen (CEA) analysis was performed in 17 cases, all of which showed a low CEA level (<192 ng/mL). All 14 cases with molecular testing showed a wild-type KRAS. Inhibin immunohistochemistry was retrospectively performed on the FNA cell blocks, inhibin was positive in six of seven cases tested. In 15 cases with concurrent FNA and FNB biopsies, the diagnosis of SCA was seen in only one FNA case (7%) but 13 FNB cases (87%).

CONCLUSIONS

This study suggests that FNA diagnosis of SCA remains challenging even with ancillary testing including cyst fluid CEA level and KRAS mutation analysis. Adjunct inhibin immunostaining may help improve the cytologic diagnosis of selective SCA cases. FNB appears superior to FNA for a definite diagnosis of SCA.

A Serous Cystic Tumor and a Pancreatic Neuroendocrine Tumor in the Same Patient: A Case Report and Literature Review

A serous cystic tumor is a rare entity that has a benign course. Its imaging characteristics, such as the presence of multiple cysts with or without nodular enhancement, can simulate other cystic or solid lesions of the pancreas. Identification of the enhancing scar with punctate calcifications on computed tomography (CT) or magnetic resonance imaging (MRI) may be a distinctive finding suggesting this diagnosis. Neuroendocrine tumors of the pancreas are a different and also rare entity. In images, they have early arterial enhancement. In MRI, they are hyperintense on T2 and hypointense on T1, with avid contrast enhancement. A case of a patient with two focal lesions in the pancreas is presented and the importance of integrating clinical findings, semiology in diagnostic images and, if applicable, the histopathological result for the optimal management of pancreatic tumors is illustrated, highlighting the crucial role of a radiologist in this process.

EUS-guided fine needle aspiration-based clues to mistaken or uncertain identity: serous pancreatic cysts

BACKGROUND/OBJECTIVES

Pancreatic serous cystic neoplasms (SCN) present a diagnostic challenge given their increasing frequency of detection and benign nature yet relatively high rate of misdiagnosis. Here, imaging and analyses associated with EUS-guided fine-needle aspiration (EUS-FNA) are evaluated for their ability to provide a correct preoperative diagnosis of SCN.

METHODS

A surgical cohort with confirmed pathological diagnosis of SCN (n = 62) and a surveillance cohort with likely SCN (n = 31) were assessed for imaging (CT/MRI/EUS) and EUS-FNA-based analyses (cytology/DNA analysis for Von Hippel-Lindau [VHL] gene alterations/biomarkers).

RESULTS

In the surgical cohort, CT/MRI and EUS respectively predicted SCN in 4 of 58(7%) and 19 of 62(31%). Cyst fluid cytology and VHL alterations predicted SCN in 1 of 51(2%) and 5 of 21(24%), respectively. High specificity cyst fluid biomarkers (vascular endothelial growth factor [VEGF]/glucose/carcinoembryonic antigen [CEA]/amylase) correctly identified SCN in 25 of 27(93%). In the surveillance cohort, cyst fluid biomarkers predicted SCN in 12 of 12(100%) while VHL alterations identified SCN 3 of 10(30%).

CONCLUSION

High specificity cyst fluid biomarkers provided the most sensitive means of diagnosing SCN preoperatively. To obtain a preoperative diagnosis of SCN at the highest level of certainty, a multidisciplinary approach should be taken to inform appropriate SCN management.

Serous Cystadenoma: A Review on Diagnosis and Management

Incidental pancreatic cysts are highly prevalent, with management dependent on the risk of malignant progression. Serous cystadenomas (SCAs) are the most common benign pancreatic cysts seen on imaging. They have typical morphological patterns but may also show atypical features that mimic precancerous and cancerous cysts. If a confident diagnosis of SCA is made, no further follow-up is warranted. Therefore, a preoperative distinction between SCA and precancerous or cancerous lesions is critically essential. Distinguishing an SCA from other types of pancreatic cysts on imaging remains a challenge, thus leading to misdiagnosis and ramifications. This review summarizes the current evidence on diagnosing and managing SCA.

Addressing the unmet clinical need for low-volume assays in early diagnosis of pancreatic cancer

The incidental detection of pancreatic cysts, an opportunity for the early detection of pancreatic cancer, is increasing, owing to an aging population and improvements in imaging technology. The classification of pancreatic cystic precursors currently relies on imaging and cyst fluid evaluations, including cytology and protein and genomic analyses. However, there are persistent limitations that obstruct the accuracy and quality of information for clinicians, including the limited volume of the complex, often acellular, and proteinaceous milieu that comprises pancreatic cyst fluid. The constraints of currently available clinical assays lead clinicians to the subjective and inconsistent application of diagnostic tools, which can contribute to unnecessary surgery and missed pancreatic cancers. Herein, we describe the pathway toward pancreatic cyst classification and diagnosis, the volume requirements for several clinically available diagnostic tools, and some analytical and diagnostic limitations for each assay. We then discuss current and future work on novel markers and methods, and how to expand the utility of clinical pancreatic cyst fluid samples. Results of ongoing studies applying SERS as a detection mode suggest that 50 μL of pancreatic cyst fluid is more than sufficient to accurately rule out non-mucinous pancreatic cysts with no malignant potential from further evaluation. This process is expected to leave sufficient fluid to analyze a follow-up, rule-in panel of markers currently in development that can stratify grades of dysplasia in mucinous pancreatic cysts and improve clinical decision-making.

Low-Pass Genomic Sequencing Reveals Novel Subtypes of Pancreatic Cystic Neoplasms

BACKGROUND

Over the years, the detection rate of pancreatic cystic neoplasms (PCNs) has significantly increased; however, the differential diagnosis and identification of high-risk PCNs remain challenging. We sought to investigate whether chromosomal instability (CIN) features in cell-free DNA in the cystic fluid of PCNs could help to identify high-risk PCNs.

METHODS

Pancreatic cystic fluid samples from 102 patients with PCNs were intraoperatively collected for detection of CIN using an ultrasensitive chromosomal aneuploidy detector. Clinical and imaging data were retrospectively collected, and statistical analysis was performed to assess the potential role of CIN in clinical practice.

RESULTS

CIN was investigated in a total of 100 patients. Sixteen of 26 serous cystic cystadenomas (SCAs) harbored deletions of chr3p and/or chr6p, whereas low rates of CIN were detected in mucinous cystic neoplasms. Most malignant PCNs presented with more than one type of CIN; amplification of chr1q and chr8q found in nine and seven of 11 malignant PCNs (81.8% and 63.6%), respectively, could aid in distinguishing high-risk IPMNs from low-risk ones, with a higher sensitivity than imaging. A combination of the mural nodule imaging feature and amplification of chr1q and chr8q achieved a sensitivity of 70.0% and a specificity of 82.4% in identifying high-risk IPMNs.

CONCLUSIONS

Our work revealed the distinct CIN signature of different types of PCNs. Deletions of chr3p and chr6p defined a subtype of SCAs. Gains of chr1q and chr8q were associated with insidious malignant PCNs and helped identify high-risk IPMNs.

Acinar Cystic Transformation of the Pancreas: Histomorphology and Molecular Analysis to Unravel its Heterogeneous Nature

Acinar cystic transformation (ACT) of the pancreas, previously called acinar cell cystadenoma, is a poorly understood and rare entity among pancreatic cystic lesions. This study aims to clarify its real nature. This research cohort included 25 patients with pancreatic ACT, representing the largest series in the literature. We describe their clinicopathological features and molecular profile using next-generation sequencing. ACT arose more often in women (F/M≃2:1), in the body-tail region, with a mean size of ~4 cm. At the latest follow-up, all patients were alive and disease free. Histologically, a typical acinar epithelium lined all cysts, intermingled with ductal-like epithelium in 11/25 (44%) cases. All the cases lacked any evidence of malignancy. Three ACT showed peculiar features: 1 showed an extensive and diffuse microcystic pattern, and the other 2 harbored foci of low-grade pancreatic intraepithelial neoplasia (PanIN) in the ductal-like epithelium. Next-generation sequencing revealed the presence of 2 pathogenic/likely pathogenic mutations in 2 different cases, 1 with ductal-like epithelium and 1 with PanIN, and affecting KRAS (c.34G>C, p.G12R) and SMO (c.1685G>A, p.R562Q) genes, respectively. The other case with PanIN was not available for sequencing. Overall, our findings support that ACT is a benign entity, potentially arising from heterogeneous conditions/background, including: (1) acinar microcysts, (2) malformations, (3) obstructive/inflammatory setting, (4) genetic predisposition, (5) possible neoplastic origin. Although all indications are that ACT is benign, the potential occurrence of driver mutations suggests discussing a potential role of long-term surveillance for these patients.

Retroperitoneal-first dissection approach at the dorsal space for a huge serous cystic neoplasm of the pancreatic tail: a case report

BACKGROUND

Large tumors of serous cystic adenomas in the pancreatic body-to-tail severely compress the surrounding organs and retroperitoneal space.

CASE PRESENTATION

We present a unique surgical challenge for distal pancreatectomy (DP). We present the case of a patient who had a massive mass lesion measuring more than 20 cm in size that had been misdiagnosed as a retroperitoneal tumor by the previous hospital. However, an expert radiologist at our institute diagnosed serous cystadenoma of the pancreas based on imaging characteristics. We decided to perform retroperitoneal space first dissection using a small incision because we were concerned about tumor infiltration or compressive adhesions in important retroperitoneal vessels. We safely attempted distal pancreatectomy by limiting the laparotomy incision step-by-step while securing the main vascular injury of the retroperitoneum. In addition to the ordinary cooperation with urological surgeons, this technique is referred to by the concept of retroperitoneal procedures for minimally invasive surgery in urology.

CONCLUSIONS

This approach is useful for lifting resected specimens by prior and wide retroperitoneal dissection, which may lead to safety and the prevention of unexpected vascular injury.

The Diagnostic Challenge of Evaluating Small Biopsies from the Pancreatobiliary System

Examination of fine needle aspirations and small core biopsies of the pancreas can be an extremely difficult and treacherous area for the diagnostic pathologist. The pancreas often yields small and often fragmented specimens, which, in combination with the morphologic overlap between numerous neoplastic and nonneoplastic mimickers, generate multiple potential diagnostic pitfalls. The authors review this challenging topic and provide insight into resolving these pitfalls using morphologic pattern recognition and ancillary testing.

Integrating Molecular Analysis into the Pathologic Evaluation of Pancreatic Cysts

The development of cross-sectional imaging techniques has enhanced the detection of pancreatic cystic lesions (PCLs). PCLs are found in approximately 2% of the general population, often as incidentally detected lesions on computed tomography or MRI during the evaluation of other medical conditions. Broadly, PCLs are classified as mucinous or nonmucinous. Mucinous PCLs include mucinous cystic neoplasms and intraductal papillary mucinous neoplasms. Nonmucinous PCLs include pseudocysts, serous cystadenomas, solid pseudopapillary neoplasms, and cystic pancreatic neuroendocrine tumors, as well as cystic acinar cell carcinoma, cystic degeneration of pancreatic ductal adenocarcinoma, lymphoepithelial cyst, and others.

Comparison of clinicopathologic characteristics and survival outcomes between invasive IPMN and invasive MCN: A population-based analysis

Background

Intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN) are two main histological subtypes of pancreatic cystic neoplasms with rapidly increasing incidence recently. The natural histories, treatment patterns, and survival outcomes of invasive IPMN and invasive MCN have not been well explored.

Methods

Patients with a diagnosis of invasive IPMN and invasive MCN in the SEER database from 2000 through 2018 were retrospectively identified. Multivariable Cox regression analysis was conducted to determine the independent risk factors associated with overall survival (OS). Subgroup analyses of survival outcomes for invasive IPMN and invasive MCN were conducted. The OS for invasive IPMN was compared between patients who underwent surgery alone and those who received surgery plus chemotherapy by propensity score matching (PSM).

Results

A total of 2,505 patients were included, of whom 2,300 were diagnosed with invasive IPMN and 205 were diagnosed with invasive MCN. Half of the invasive IPMN (48.4%) and three-quarters of the invasive MCN (76.1%) patients were female. Of all patients, both the OS and cancer-specific survival were significantly better in the invasive MCN cohort compared to the invasive IPMN cohort. In subgroup analyses, while invasive MCN experienced better OS compared to invasive IPMN in the subgroups of patients with local–regional disease, the survival advantages disappeared in patients at a distant stage. In addition, surgery plus chemotherapy in invasive IPMN patients was associated with significantly better survival compared to surgery alone after PSM.

Conclusion

We examined the demographic and clinical characteristics between invasive IPMN and invasive MCN patients using a large-population-based analysis. Although the OS is significantly better for invasive MCN versus invasive IPMN, the difference disappeared in patients with distant disease. A combination of surgery and chemotherapy in selected invasive IPMN patients could confer survival benefits compared to surgery alone.

Cystic Neoplasms of the Pancreas: Differential Diagnosis and Radiology Correlation

Although the probability of pancreatic cystic neoplasms (PCNs) being detected is raising year by year, their differential diagnosis and individualized treatment are still a challenge in clinical work. PCNs are tumors containing cystic components with different biological behaviors, and their clinical manifestations, epidemiology, imaging features, and malignant risks are different. Some are benign [e.g., serous cystic neoplasms (SCNs)], with a barely possible that turning into malignant, while others display a low or higher malignant risk [e.g., solid pseudopapillary neoplasms (SPNs), intraductal papillary mucinous neoplasms (IPMNs), and mucinous cystic neoplasms (MCNs)]. PCN management should concentrate on preventing the progression of malignant tumors while preventing complications caused by unnecessary surgical intervention. Clinically, various advanced imaging equipment are usually combined to obtain a more reliable preoperative diagnosis. The challenge for clinicians and radiologists is how to accurately diagnose PCNs before surgery so that corresponding surgical methods and follow-up strategies can be developed or not, as appropriate. The objective of this review is to sum up the clinical features, imaging findings and management of the most common PCNs according to the classic literature and latest guidelines.

Pancreatic Cystic Lesions and Malignancy: Assessment, Guidelines, and the Field Defect

The widespread use of high-spatial-resolution cross-sectional imaging has led to an increase in detection of incidental pancreatic cystic lesions. These lesions are a diverse group, ranging from indolent and premalignant lesions to invasive cancers. The diagnosis of several of these lesions can be suggested on the basis of their imaging appearance, while many other lesions require follow-up imaging and/or aspiration. The smaller cystic lesions, often branch-duct intraductal papillary mucinous neoplasms, have overlapping imaging characteristics that make diagnostic assessment of the natural history and malignancy risk confusing. Expert panels have developed societal guidelines, based on a consensus, for surveillance of these lesions. However, these guidelines are often inconsistent and are constantly evolving as additional scientific data are accumulated. Identification of features associated with increased risk of malignancy is important for proper management. The concept of field defect, whereby pancreatic adenocarcinoma develops at a site different from the site of the pancreatic cyst, adds to the complexity of screening guidelines. As a result of the differences in guidelines, key stakeholders (eg, radiologists, gastroenterologists, and surgeons) must review and come to a consensus regarding which guideline, or combination of guidelines, to follow at their individual institutions. Standardized reporting and macros are helpful for ensuring the uniformity of interpretations. Radiologists play a critical role in the detection and characterization of pancreatic cystic lesions, in the follow-up recommendations for these lesions, and in the detection of associated cancer. An invited commentary by Zaheer is available online. Online supplemental material is available for this article. ^©RSNA, 2021.

Preliminary evaluation of 18F-FDG-PET/MRI for differentiation of serous from nonserous pancreatic cystic neoplasms: a pilot study

OBJECTIVES

The aim of the study was to evaluate preliminary feasibility of 18F-FDG-PET/MRI in differentiation of pancreatic serous cystic neoplasms (SCNs) from non-SCNs.

METHODS

From August 2017 to June 2019, 10 patients (3 men, 7 women; mean age, 63 years) previously diagnosed with pancreatic cystic neoplasm underwent simultaneous 18F-FDG-PET/MRI prospectively on an integrated 3-Tesla hybrid PET/MRI scanner. PET images were analyzed visually and semiquantitatively measuring standardized uptake values (SUV) including lesion SUVmax and SUVmean, lesion to pancreas and lesion to liver SUVmax and SUVmean ratio independent of MRI diagnosis. The reference standard for lesion diagnosis was by MRI features and interval follow-up.

RESULTS

Visual assessment of PET images demonstrated uptake in 57% of SCNs. Lesion to liver SUVmax ratio of ≥0.5 showed the highest accuracy (90%) and area under the curve (0.9) followed by lesion SUVmax of ≥1.6 and lesion to pancreas SUVmax ratio of ≥0.77 for diagnosis of SCN. The sensitivity for lesion SUVmax of ≥1.6 was less than two other ones (71 versus 100%). All non-SCNs exhibited SUVmax value less than 1.6 while 33 and 66% demonstrated lesion to liver SUVmax ratio of >0.5 and lesion to pancreas SUVmax ratio of >0.77, respectively. PET/MRI specificity was 67, 100, 67 and 33% through lesion to liver SUVmax ratio, lesion SUVmax, lesion SUVmean and lesion to pancreas SUVmax ratio, respectively, for diagnosis of SCN.

CONCLUSION

Preliminary results show that PET/MRI utilization is promising for differentiation of pancreatic SCN from non-SCN lesions. This could reduce need for surveillance imaging or avoidance of unnecessary intervention in pancreatic cystic neoplasms with uncertain diagnoses.

CT-Based Radiomics Analysis for Preoperative Diagnosis of Pancreatic Mucinous Cystic Neoplasm and Atypical Serous Cystadenomas

Objectives

To investigate the value of CT-based radiomics analysis in preoperatively discriminating pancreatic mucinous cystic neoplasms (MCN) and atypical serous cystadenomas (ASCN).

Methods

A total of 103 MCN and 113 ASCN patients who underwent surgery were retrospectively enrolled. A total of 764 radiomics features were extracted from preoperative CT images. The optimal features were selected by Mann-Whitney U test and minimum redundancy and maximum relevance method. The radiomics score (Rad-score) was then built using random forest algorithm. Radiological/clinical features were also assessed for each patient. Multivariable logistic regression was used to construct a radiological model. The performance of the Rad-score and the radiological model was evaluated using 10-fold cross-validation for area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

Results

Ten screened optimal features were identified and the Rad-score was then built based on them. The radiological model was built based on four radiological/clinical factors. In the 10-fold cross-validation, the Rad-score was proved to be robust and reliable (average AUC: 0.784, sensitivity: 0.847, specificity: 0.745, PPV: 0.767, NPV: 0.849, accuracy: 0.793). The radiological model performed slightly less well in classification (average AUC: average AUC: 0.734 sensitivity: 0.748, specificity: 0.705, PPV: 0.732, NPV: 0.798, accuracy: 0.728.

Conclusions

The CT-based radiomics analysis provided promising performance for preoperatively discriminating MCN from ASCN and showed good potential in improving diagnostic power, which may serve as a novel tool for guiding clinical decision-making for these patients.

Multiparameter Analysis Using 18F-FDG PET/CT in the Differential Diagnosis of Pancreatic Cystic Neoplasms

Purpose

To evaluate multiparametric analysis in differential diagnosis between pancreatic serous cystic neoplasms (SCNs) and mucinous cystic neoplasms (MCNs) as well as the differentiation of the benign and malignant MCNs with ¹⁸F-FDG (18-fluorodeoxyglucose) PET/CT (positron emission tomography).

Methods

Forty patients with total of 41 lesions (SCNs: 27/41; MCNs: 14/41), who were preoperatively examined with ¹⁸F-FDG PET/CT, were retrospectively analyzed. Multiple quantitative parameters using conventional and texture features were included. The combined model was established with complementary PET/MR parameters. The differential diagnostic efficacy of each independent parameter and the combined model were evaluated with receiver operating characteristic (ROC) analysis. Integrated discriminatory improvement (IDI) and net reclassification improvement (NRI) were used to evaluate improvement of diagnostic efficacy by using combination of multiple parameters.

Results

Among all independent parameters, the percentile 5th (0.88 ± 0.38 vs 0.47 ± 0.23, P < 0.001) showed the highest discriminative diagnostic value. The combination of multiple parameters can improve the differential diagnostic efficacy of SCNs and MCNs (sensitivity = 71.4%, specificity = 77.8%, and AUC = 0.788), and the addition of texture parameters to the conventional parameters allowed a significant reclassification with IDI = 0.236 (95% CI: 0.095-0.377) and categorical NRI = 0.434 (95% CI: 0.030-0.838). SURmax (tumor to normal pancreas ratio, T/P) and SURmax (tumor to aorta ratio, T/A) both showed the highest discriminative diagnostic value (sensitivity = 100.0%, specificity = 70.0%, AUC = 0.900, and Youden index = 0.700) in the differential diagnosis of benign and malignant MCNs, with the cutoff values of 0.84 and 0.90, respectively.

Conclusion

Combination of multiple parameters using ¹⁸F-FDG PET/CT could further improve differentiation between pancreatic SCNs and MCNs. SURmax (T/P) and SURmax (T/A) could improve differential diagnosis of benign and malignant MCNs.

Ectopic pancreas appearing as a giant gastric cyst mimicking gastric lymphangioma: a case report and a brief review

Background

Ectopic pancreas (EP) is defined as pancreatic tissue that lacks anatomical or vascular communication with the normal body of the pancreas. Despite improvements in diagnostic endoscopy and imaging studies, differentiating ectopic pancreatic tissue from gastric submucosal diseases remains a challenge.

Case presentation

Here, we present a case of a 44-year-old woman with severe epigastric pain. Initially, gastric lymphangioma was highly suspected due to a well-demarcated protruding mass with a large size that occurred in the submucosal layer of the gastric antrum and appeared as a cystic lesion. The final correct diagnosis of gastric EP was made during surgery.

Conclusion

Gastric EP with serous oligocystic adenoma appearing as a giant gastric cyst is extremely rare. The difficulty of making an accurate diagnosis and differential diagnosis is highlighted, which may provide additional clinical experience for the diagnosis of EP with serous oligocystic adenoma in the stomach.

Practical Applications of Molecular Testing in the Cytologic Diagnosis of Pancreatic Cysts

Mucinous pancreatic cysts are precursor lesions of ductal adenocarcinoma. Discoveries of the molecular alterations detectable in pancreatic cyst fluid (PCF) that help to define a mucinous cyst and its risk for malignancy have led to more routine molecular testing in the preoperative evaluation of these cysts. The differential diagnosis of pancreatic cysts is broad and ranges from non-neoplastic to premalignant to malignant cysts. Not all pancreatic cysts—including mucinous cysts—require surgical intervention, and it is the preoperative evaluation with imaging and PCF analysis that determines patient management. PCF analysis includes biochemical and molecular analysis, both of which are ancillary studies that add significant value to the final cytological diagnosis. While testing PCF for carcinoembryonic antigen (CEA) is a very specific test for a mucinous etiology, many mucinous cysts do not have an elevated CEA. In these cases, detection of a KRAS and/or GNAS mutation is highly specific for a mucinous etiology, with GNAS mutations supporting an intraductal papillary mucinous neoplasm. Late mutations in the progression to malignancy such as those found in TP53, p16/CDKN2A, and/or SMAD4 support a high-risk lesion. This review highlights PCF triage and analysis of pancreatic cysts for optimal cytological diagnosis.

Novel expression of vascular endothelial growth factor isoforms in the pancreas and pancreatic cystic lesions

Vascular endothelial growth factor (VEGF)-A is known to play key biological roles in angiogenesis and vascular permeability. We previously identified VEGF-A as an accurate biomarker of benign pancreatic cystic lesions known as serous cystic neoplasms (SCN). In the present study, we seek to further characterize the expression of VEGF-A and its splice isoforms in different pancreatic cysts including SCN. Patients undergoing surgery were consented for the collection of pancreatic cystic lesion tissue (SCN, pseudocysts, mucinous cysts) and normal adjacent pancreas as well as pancreatic cyst fluid. Following RNA isolation from the tissues, relative VEGF-A gene expression was quantitatively analyzed using real-time PCR (qPCR), and VEGF-A isoform expression was evaluated by reverse transcriptase (RT)-PCR. Relative VEGF-A gene expression was significantly increased in SCN, demonstrating transcriptional upregulation in SCN compared to other pancreatic cyst tissues (P < 0.0001). VEGF-189, -165, -145, and -121 splice variants were detected in both normal adjacent pancreas and pancreatic cystic lesions; the novel VEGF-111 isoform was variably expressed in normal and cyst tissues. Finally, VEGF isoform levels in pancreatic cyst fluid were measured by isoform-specific ELISAs. VEGF-165, -145, and -121 proteins were present in pancreatic cyst fluids; VEGF-165 levels were significantly higher in SCN cyst fluid. Thus, multiple VEGF isoforms were expressed in normal pancreas and pancreatic cysts. Of particular interest are VEGF-145 and -111, which have not previously been described in human pancreas where they may exhibit unique biological activities in health and/or disease.

Loss of Jag1 cooperates with oncogenic Kras to induce pancreatic cystic neoplasms

Notch signaling exerts both oncogenic and tumor-suppressive functions in the pancreas. In this study, deletion of Jag1 in conjunction with oncogenic Kras ^G12D expression in the mouse pancreas induced rapid development of acinar-to-ductal metaplasia and early stage pancreatic intraepithelial neoplasm; however, culminating in cystic neoplasms rather than ductal adenocarcinoma. Most cystic lesions in these mice were reminiscent of serous cystic neoplasm, and the rest resembled intraductal papillary mucinous neoplasm. Jag1 expression was lost or decreased in cystic lesions but retained in adenocarcinoma in these mice, so was the expression of Sox9. In pancreatic cancer patients, JAG1 expression is higher in cancerous tissue, and high JAG1 is associated with poor overall survival. Expression of SOX9 is correlated with JAG1, and high SOX9 is also associated with poor survival. Mechanistically, Jag1 regulates expression of Lkb1, a tumor suppressor involved in the development of pancreatic cystic neoplasm. Collectively, Jag1 can act as a tumor suppressor in the pancreas by delaying precursor lesions, whereas loss of Jag1 promoted a phenotypic switch from malignant carcinoma to benign cystic lesions.

The Diagnostic Accuracy of Mutant KRAS Detection from Pancreatic Secretions for the Diagnosis of Pancreatic Cancer: A Meta-Analysis

This meta-analysis aims to identify the diagnostic accuracy of mutations in the Kirsten Rat Sarcoma (KRAS) oncogene in the diagnosis of pancreatic ductal adenocarcinoma (PDAC). The survival of PDAC remains poor often due to the fact that disease is advanced at diagnosis. We analysed 22 studies, with a total of 2156 patients, to identify if the detection of KRAS mutations from pancreatic exocrine secretions yields sufficient specificity and sensitivity to detect patients with PDAC amongst healthy individuals. The majority of the studies were retrospective, samples were obtained endoscopically or surgically, and included comparator populations of patients with chronic pancreatitis and pre-malignant pancreatic lesions (PanIN) as well as healthy controls. We performed several analyses to identify the diagnostic accuracy for PDAC among these patient populations. Our results highlighted that the diagnostic accuracy of KRAS mutation for PDAC was of variable sensitivity and specificity when compared with PanINs and chronic pancreatitis, but had a higher specificity among healthy individuals. The sensitivity of this test must be improved to prevent missing early PDAC or PanINs. This could be achieved with rigorous prospective cohort studies, in which high-risk patients with normal cross-sectional imaging undergo surveillance following KRAS mutation testing.

Molecular Diagnosis of Cystic Neoplasms of the Pancreas: a Review

BACKGROUND

The prevalence of incidental pancreatic cystic neoplasms (PCNs) has increased dramatically with advancements in cross-sectional imaging. Diagnostic imaging is limited in differentiating between benign and malignant PCNs. The aim of this review is to provide an overview of biomarkers that can be used to distinguish PCNs.

METHODS

A review of the literature on molecular diagnosis of cystic neoplasms of the pancreas was performed.

RESULTS

Pancreatic cysts can be categorized into inflammatory and non-inflammatory lesions. Inflammatory cysts include pancreatic pseudocysts. Noninflammatory lesions include both mucinous and non-mucinous lesions. Mucinous lesions include intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm. Non-mucinous lesions include serous cystadenoma and solid-pseudopapillary tumor of the pancreas. Imaging, cyst aspiration, and histologic findings, as well as carcinoembryonic antigen and amylase are commonly used to distinguish between cyst types. However, molecular techniques to detect differences in genetic mutations, protein expression, glycoproteomics, and metabolomic profiling are important developments in distinguishing between cyst types.

DISCUSSION

Nomograms incorporating common clinical, laboratory, and imaging findings have been developed in a better effort to predict malignant IPMN. The incorporation of top molecular biomarker candidates to nomograms may improve the predictive ability of current models to more accurately diagnose malignant PCNs.

Management of Incidental Pancreatic Cystic Lesions: Integrating Novel Diagnostic and Prognostic Factors With Current Clinical Guidelines

Owing to increased detection rates, the diagnosis and management of incidental pancreatic cysts has become a common predicament. Up to 13% of patients undergoing cross-sectional imaging studies for other indications are found to have pancreatic cystic lesions. Although most cystic lesions are benign, the malignant potential of several types of pancreatic cysts makes accurate classification vital to directing therapy. To this end, advances in the last decade led to better characterization of pancreatic cyst morphology and hence enhanced the ability to predict underlying histopathology, and biological behavior. Although accurate classification remains a challenge, the utilization of complementary diagnostic tools is the optimal approach to dictate management. The following review includes a description of pancreatic cysts, a critical review of current and emerging diagnostic techniques and a review of recent guidelines in the management of incidental pancreatic cysts.

EUS-FNA diagnosis of pancreatic serous cystadenoma with the aid of cell blocks and α-inhibin immunochemistry: A case series

Serous cystadenoma (SCA) is an uncommon benign pancreatic neoplasm that is most often managed conservatively with follow-up rather than surgical excision. Therefore, to avoid the serious complications of pancreatic surgery, SCA should be diagnosed accurately at the preoperative level. Preoperative SCA diagnosis requires a multimodal diagnostic approach that includes imaging, cystic fluid biochemical analysis and/or endoscopic ultrasound fine-needle aspiration (EUS-FNA). In this brief report, we describe six EUS-FNA cases from five patients that were reported as "benign, consistent with serous cystadenoma". Samples were hypocellular, composed of loose clusters and single cuboidal, bland-looking cells among epithelial sheets representing gastrointestinal contamination. Cell blocks were prepared and all six FNA cases revealed cuboidal cells with a positive α-inhibin immunophenotype, consistent with a diagnosis of SCA. As EUS-FNAs of SCA commonly result in non-diagnostic interpretations, cell block preparations with subsequent immunochemistry can increase their diagnostic accuracy and guide patient management.

Cytological appearance of pancreatic cystosis on fine-needle aspiration

A 22-year-old Caucasian male with cystic fibrosis and recently diagnosed insulin-dependent diabetes mellitus underwent magnetic resonance imaging (MRI) and was found to have multiple cystic lesions in the pancreas. Endoscopic ultrasound evaluation revealed multiple macro- and microcystic components without mural nodules. One of the cysts in the body of the pancreas was in clear direct communication with the nondilated main pancreatic duct. Fine-needle aspiration (FNA) of two cysts was performed and showed foamy macrophages and rare ductal as well as acinar cells. Cell blocks showed nonpolarizable pink crystalloid material and small nonlaminated concretions consistent with inspissated secretions. Special stains for chymotrypsin and trypsin highlighted the acinar cells. Periodic acid Schiff, with and without diastase, was negative. Biopsy of the cyst wall showed ductal epithelial cells with underlying fibrotic stroma. This is the first description of the FNA appearance of pancreatic cystosis. We discuss the cytological differential diagnosis of cystic lesions of the pancreas and the biochemical as well as imaging findings used to arrive at the diagnosis.

Role of Ancillary Testing on Endoscopic US-Guided Fine Needle Aspiration Samples from Cystic Pancreatic Neoplasms

Pancreatic cysts are increasingly detected on imaging studies. Accurate determination of the cyst type is important to provide appropriate care for the patients. It is also very clear that not one single modality can provide adequate diagnostic information. A multidisciplinary approach is the key to the diagnosis of pancreatic cysts. In this setting, the role of ancillary testing, which includes biochemical testing (carcinoembryonic antigen and amylase levels in the cyst), molecular testing (e.g., KRAS, GNAS, VHL, and CTNB1), and/or immunohistochemical tests are very important to obtain an accurate diagnosis. This review will discuss helpful ancillary tests in common pancreatic cyst neoplasms and how to approach the diagnosis of pancreatic cysts.

Serous Neoplasms of the Pancreas: A Comprehensive Review

Serous neoplasms are uncommon, usually cystic tumors that account for less than 1% of all primary pancreatic lesions. They consist predominantly of a monomorphic epithelial cell population with a glycogen-rich, clear cytoplasm, reminiscent of clear cell renal cell carcinoma, with which serous neoplasms share an association with underlying VHL loss-of-function mutations. Serous neoplasms have no metastatic potential. Accurate recognition of this entity, including its various architectural subtypes, is critical to appropriate prognostication and treatment. Immunohistochemical detection of inhibin and calponin expression, along with the absence of both estrogen and progesterone receptors and nuclear β-catenin, can help to distinguish serous neoplasms from mimics. With the advent of minimally invasive and molecularly driven diagnostic techniques, the pathologist's role in the assessment and management of serous neoplasms has become increasingly complex and important. We provide an update on the histologic, immunohistochemical, and molecular features of pancreatic serous neoplasms for the practicing pathologist.

Serous Cystadenoma of the Pancreas With Complex Florid Papillary Architecture: A Case Report and Review of the Literature

Serous cystadenoma (SCA) is a relatively rare benign pancreatic neoplasm. It has a very distinctive gross and microscopic appearance including pure and mixed microcystic and macrocystic patterns as well as rare solid architectural pattern. In this article, we present a rare case of SCA with a complex florid papillary architecture. A 40-year-old man was diagnosed with a 3.5 cm SCA of the uncinate process of the pancreas based on abdominal computed tomography scan. The tumor was monitored radiographically until recent magnetic resonance imaging showed a new 1.0-cm eccentric mural nodule within the tumor with multiple arterial enhancing septations and features suspicious for a neuroendocrine tumor. A pylorus-preserving Whipple procedure was subsequently performed and the mass was resected. Gross examination confirmed the radiological findings of a well-demarcated, 3.5 cm multicystic pancreatic lesion with a 1.0 cm circumscribed, tan solid nodule at its periphery. Microscopic evaluation revealed a predominantly microcystic pattern classical of SCA with occasional macrocysts. The 1.0 cm discrete nodule was also a SCA, but showed unusually exuberant complex papillary growth. To our knowledge, this is the first reported case describing this morphologic variant. Recognition of this rare and unusual pattern is important to avoid misdiagnosis, especially on small biopsy specimens.

Pseudo solid-appearing pancreatic serous microcystic adenomas: Histologic diagnosis with the EUS core biopsy fork-tip needle

Background and Objectives:

Despite rarely, serous cystic adenoma (SCA) can assume a pseudo-solid aspect mimicking other pancreatic neoplasm as neuroendocrine tumor. EUS-FNA cytology has low diagnostic accuracy due to the scant cellularity of the collected samples. Histological diagnosis is usually made after resection. Recently, end-cutting needles for EUS-fine-needle biopsy (EUS-FNB), which obtain tissue cores by penetrating the lesions, have been developed. We aimed to assess the capability of EUS-FNB with SharkCore™ needles in the preoperative diagnosis of serous cystic adenoma pseudo-solid-appearing on imaging (Sa-SCA).

Materials and Methods:

Between January 2016 and January 2018, data from consecutive adult patients, who were referred for EUS-FNB of a solid pancreatic lesion and were diagnosed with having SCA, were retrieved from a single-center institutional database.

Results:

Two patients were excluded because of microcystic aspect at EUS. Histological diagnosis of SCA was made by EUS-FNB in the remaining 7 patients (5 females; mean age of 62.5 years). Lesions (mean size of 19.8 mm) were hypervascular on cross-sectional imaging, slightly hyperdense magnetic resonance imaging with T2-weighted images can, and negative at ⁶⁸Ga-somatostatin receptor positron emission tomography and ¹⁸fluoro-deoxyglucose positron emission tomography. EUS-FNB samples were judged adequate for a definitive diagnosis in all cases, achieving specimens suitable for histological evaluation and several ancillary stains. Histochemical positivity for periodic acid-Schiff (PAS) and PAS with diastase digestion was observed in 7/7 cases. Immunohistochemical positivity for α-inhibin (7/7), GLUT1 (6/6), MUC6 (5/5), and negativity for synaptophysin (7/7) and chromogranin A (2/2) favored SCA diagnosis.

Conclusions:

In the case of preoperative workup suspected for Sa-SCA, a “forward acquiring” needle could improve the rate of preoperative histological diagnosis.

Current indications and yield of endoscopic ultrasound and ancillary techniques in pancreatic cystic neoplasms

An increase in the diagnosis of pancreatic cystic neoplasm has been described lately. Surgical treatment or surveillance is advised depending on the type of lesion diagnosed. The most accurate diagnostic approach is needed to make the best therapeutic decision. Endoscopic ultrasound is a very valuable tool in the evaluation of pancreatic cystic neoplasm. It generates high-quality images and allows the possibility of sampling the cystic fluid for cytology, microbiological and molecular evaluation. Even with this evaluation, the sensitivity of this approach is not always adequate. New technological resources have been developed to try to improve the diagnostic accuracy of pancreatic cystic neoplasms. The two most promising techniques are needle-based confocal laser endomicroscopy and contrast-enhanced harmonic endoscopic ultrasound. Needle-based confocal laser endomicroscopy allows a microscopic evaluation of mucosal glands and vascular pattern, to differentiate mucinous from non-mucinous lesions. Contrast-enhanced harmonic endoscopic ultrasound is used for the vascular evaluation of the microcirculation of the cyst wall and mural nodule, mainly to make the difference between malignant nodules and mucus plugs. A combination of these different diagnostic techniques can improve the diagnostic accuracy of pancreatic cystic neoplasms to offer the adequate therapeutic decision.

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.

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.

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.

Benign Tumors and Tumorlike Lesions of the Pancreas

The pancreas is a complex organ that may give rise to large number of neoplasms and non-neoplastic lesions. This article focuses on benign neoplasms, such as serous neoplasms, and tumorlike (pseudotumoral) lesions that may be mistaken for neoplasm not only by clinicians and radiologists, but also by pathologists. The family of pancreatic pseudotumors, by a loosely defined conception of that term, includes a variety of lesions including heterotopia, hamartoma, and lipomatous pseudohypertrophy. Autoimmune pancreatitis and paraduodenal ("groove") pancreatitis may also lead to pseudotumor formation. Knowledge of these entities will help in making an accurate diagnosis.

Serous pancreatic neoplasia, data and review

AIM

To describe the imaging features of serous neoplasms of the pancreas using ultrasound, endoscopic ultrasound, computed tomography and magnetic resonance imaging.

METHODS

This multicenter international collaboration enhances a literature review to date, reporting features of 287 histologically confirmed cases of serous pancreatic cystic neoplasms (SPNs).

RESULTS

Female predominance is seen with most SPNs presenting asymptomatically in the 5th through 7th decade. Mean lesion size was 38.7 mm, 98% were single, 44.2% cystic, 46% mixed cystic and solid, and 94% hypoechoic on B-mode ultrasound. Vascular patterns and contrast-enhancement profiles are described as hypervascular and hyperenhancing.

CONCLUSION

The described ultrasound features can aid differentiation of SPN from other neoplastic lesions under most circumstances.

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.

Precursors of pancreatic cancer

Pancreatic cancer (PC) behaves very differently in comparison with other malignancies. Its incidence has been increasing continuously; mortality has not decreased, the diagnosis is frequently late, radical surgery is performed only in 15-20% of patients, and chemotherapy is only palliative. PC occurs in three different forms. Sporadic PC accounts for 90% of all PCs. Its most frequent form is the pancreatic ductal adenocarcinoma. The remaining 10% constitute two minority groups: familial PC (7%) and PC as a manifestation of a genetic cancer syndrome (3%). PCs are preceded by a precancerous lesion (precursor). At present, six different precursors are known. They have different histomorphological characteristics and malignant potential. The recognition and correct interpretation of individual precursors influences adequate clinical decision-making. The publication surveys the present knowledge of individual precursors and their role in the early pancreatic carcinogenesis.

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

Preoperative characteristics and cytological features of 136 histologically confirmed pancreatic mucinous cystic neoplasms

BACKGROUND

Mucinous cystic neoplasms (MCNs) of the pancreas present a management conundrum. The majority are benign but all are resected due to their malignant potential. Recent studies have recommended nonsurgical management. In the current study, the authors analyzed the preoperative imaging, cytology, and cyst fluid characteristics of 136 histologically confirmed MCNs to assess predictors of a high-risk (HR) cyst for surgical triage.

METHODS

MCNs resected at the Massachusetts General Hospital between 1990 and 2014 formed the study cohort. Patient demographics, cyst size, and mural nodules (MNs) by endoscopic ultrasound, cytology, and cyst fluid carcinoembryonic antigen and amylase levels were correlated with histological grade. A HR cyst was defined as high-grade dysplasia or invasive carcinoma on histology. Performance characteristics were assessed for each parameter, with a cyst size ≥3 cm or a MN on imaging and malignant cytology considered to be "true-positive" results for predicting malignancy.

RESULTS

Only 15 of the 136 cysts had HR histology (11%). On average, patients with HR cysts were older than those with low-risk cysts (55 years vs 49 years, respectively). High-grade cytology was the most accurate predictor of malignancy (95%) followed by MN and cyst size together (88%) and MN alone (83%). The average carcinoembryonic antigen level (in ng/mL) increased with the grade of dysplasia but the ranges overlapped between low risk and HR cysts.

CONCLUSIONS

To the authors' knowledge, the current study is the largest series to date analyzing the cytological features of histologically confirmed MCN. Cytology is insensitive but very specific for detecting a HR MCN and outperformed imaging for the detection of HR MCN. Endoscopic ultrasound-guided fine-needle aspiration and cytology should be performed on any clinically suspected MCN that is being considered for conservative management. Cancer Cytopathol 2017;125:169-177. © 2016 American Cancer Society.

Pancreatic surgery for tumors in children and adolescents

PURPOSE

Pancreatic neoplasms are uncommon in children. This study sought to analyze the clinical and pathological features of surgically resected pancreatic tumors in children and discuss management strategies.

METHODS

We conducted a retrospective review of patients ≤21 years with pancreatic neoplasms who underwent surgery at a single institution between 1995 and 2015.

RESULTS

Nineteen patients were identified with a median age at operation of 16.6 years (IQR 13.5-18.9). The most common histology was solid pseudopapillary neoplasm (SPN) (n = 13), followed by pancreatic neuroendocrine tumor (n = 3), serous cystadenoma (n = 2) and pancreatoblastoma (n = 1). Operative procedures included formal pancreatectomy (n = 17), enucleation (n = 1) and central pancreatectomy (n = 1). SPNs were noninvasive in all but one case with perineural, vascular and lymph node involvement. Seventeen patients (89.5 %) are currently alive and disease free at a median follow-up of 5.7 (IQR 3.7-10.9) years. Two patients died: one with metastatic insulinoma and another with SPN who developed peritoneal carcinomatosis secondary to a concurrent rectal adenocarcinoma.

CONCLUSIONS

Pediatric pancreatic tumors are a heterogeneous group of neoplastic lesions for which surgery can be curative. SPN is the most common histology, is characterized by low malignant potential and in selected cases can be safely and effectively treated with a tissue-sparing resection and minimally invasive approach.

Glucose metabolic phenotype of pancreatic cancer

AIM: To construct a global “metabolic phenotype” of pancreatic ductal adenocarcinoma (PDAC) reflecting tumour-related metabolic enzyme expression.

METHODS: A systematic review of the literature was performed using OvidSP and PubMed databases using keywords “pancreatic cancer” and individual glycolytic and mitochondrial oxidative phosphorylation (MOP) enzymes. Both human and animal studies investigating the oncological effect of enzyme expression changes and inhibitors in both an in vitro and in vivo setting were included in the review. Data reporting changes in enzyme expression and the effects on PDAC cells, such as survival and metastatic potential, were extracted to construct a metabolic phenotype.

RESULTS: Seven hundred and ten papers were initially retrieved, and were screened to meet the review inclusion criteria. 107 unique articles were identified as reporting data involving glycolytic enzymes, and 28 articles involving MOP enzymes in PDAC. Data extraction followed a pre-defined protocol. There is consistent over-expression of glycolytic enzymes and lactate dehydrogenase in keeping with the Warburg effect to facilitate rapid adenosine-triphosphate production from glycolysis. Certain isoforms of these enzymes were over-expressed specifically in PDAC. Altering expression levels of HK, PGI, FBA, enolase, PK-M2 and LDA-A with metabolic inhibitors have shown a favourable effect on PDAC, thus identifying these as potential therapeutic targets. However, the Warburg effect on MOP enzymes is less clear, with different expression levels at different points in the Krebs cycle resulting in a fundamental change of metabolite levels, suggesting that other essential anabolic pathways are being stimulated.

CONCLUSION: Further characterisation of the PDAC metabolic phenotype is necessary as currently there are few clinical studies and no successful clinical trials targeting metabolic enzymes.