Risk of malignancy in pancreatic cysts with cytology of high-grade epithelial atypia

The World Health Organization Reporting System for Pancreaticobiliary Cytopathology: Overview and Summary

The recently published WHO Reporting System for Pancreaticobiliary Cytopathology (World Health Organization [WHO] System) is an international approach to the standardized reporting of pancreaticobiliary cytopathology, updating the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSC System). Significant changes were made to the categorization of benign neoplasms, intraductal neoplasms, mucinous cystic neoplasms, and malignant neoplasms considered low grade. Benign neoplasms, such as serous cystadenoma, categorized as Neoplastic: benign in the PSC system, are categorized as Benign/negative for malignancy in the WHO system. Pancreatic neuroendocrine tumor, solid-pseudopapillary neoplasm, and gastrointestinal stromal tumor, categorized as Neoplastic: other in the PSC system, are categorized as Malignant in the WHO System in accord with their classification in the 5th edition WHO Classification of Digestive System Tumours (2019). The two new categories of Pancreaticobiliary Neoplasm Low-risk/grade and Pancreaticobiliary Neoplasm High-risk/grade are mostly limited to intraductal neoplasms and mucinous cystic neoplasms. Low-risk/grade lesions are mucinous cysts, with or without low-grade epithelial atypia. High-risk/grade lesions contain neoplastic epithelium with high-grade epithelial atypia. Correlation with clinical, imaging, and ancillary studies remains a key tenet. The sections for each entity are written to highlight key cytopathological features and cytopathological differential diagnoses with the pathologist working in low resource setting in mind. Each section also includes the most pertinent ancillary studies useful for the differential diagnosis. Sample reports are provided for each category. Finally, the book provides a separate section with risk of malignancy and management recommendations for each category to facilitate decision-making for clinicians.

Grading Cytologic Epithelial Atypia in Pancreatic Mucinous Cysts Predicts Patient Survival: Correlation With Histologic, Molecular, and Clinical Follow-Up

Cytologic examination of epithelial cells in cyst fluids from pancreatic mucinous cysts is the optimal method for identifying high-grade atypia (HGA), which may represent histologic high-grade dysplasia (HGD) or invasive carcinoma and thereby classify the cyst as high risk, warranting surgical resection. Cytologic features of HGA were previously described at our institution in 2013 and implemented thereafter, but performance of grading with these criteria has not yet been reported. In total, 1322 pancreatic cyst fluid specimens (2014-2021) were identified; all pathology reports and relevant clinical data were reviewed in detail; and 230 unique cysts (217 patients) contained neoplastic mucinous epithelium. Of the 230 cysts, 178 had low-grade atypia (LGA), and 52 had HGA. Ninety-seven cysts had histologic follow-up: 77 (79%) were resections and 20 (21%) were diagnostic surgical biopsies only. Moreover, 92 (95%) were confirmed neoplastic mucinous cysts, 3 were adenocarcinomas, and 2 were benign entities. Among histologically confirmed neoplastic mucinous cysts, 58 had low-grade dysplasia (LGD); 34 had HGD, of which 14 also had invasive carcinoma. A significantly higher proportion of cysts with HGA (63%) demonstrated at least HGD on follow-up compared to those with LGA (26%, P < .001). The sensitivity and specificity of HGA for accurately classifying a high-risk cyst were 54% and 81%, respectively. Of the 230 cysts, 146 (64%) cysts had corresponding next-generation sequencing results; 31% of HGA cysts harbored a high-risk mutation (TP53, CDKN2A, and/or SMAD4) vs 7% of LGA cysts (P < .001). Among cysts without histologic confirmation, 25% of HGA cysts had high-risk mutation vs 7% of LGA cysts. The grade of cytologic atypia was predictive of overall survival and recurrence-free survival (P < .001 and P = .020, respectively). Implementation of cytologic criteria for HGA in pancreatic mucinous cysts has relatively low sensitivity but modest specificity for classifying a high-risk cyst. Although high-risk mutations were more commonly found in cysts with HGA, their frequency is overall low. Thus, evaluating the degree of cytologic atypia, which is predictive of patient survival, provides significant value and informs patient outcomes.

Diagnosis and Management of Pancreatic Cysts

As pancreatic cyst incidence rises, likely due to the ubiquitous increase in cross-sectional imaging, their management presents multiple challenges for both the practitioner and patient. It is critical that all pancreatic cysts are appropriately characterized, as treatment decisions depend on an accurate diagnosis. Diagnostic modalities such as cytology, biopsy, and cyst fluid biomarkers allow for definitive diagnosis of virtually all lesions. Some cysts, such as intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and cystic pancreatic endocrine neoplasms, have malignant potential and must be surveyed. Other cysts, such as serous cystadenomas and pancreatic fluid collections, do not have malignant potential. Surveillance strategies vary widely depending on cyst type and size and while multiple medical societies advocate surveillance, their published surveillance guidelines are heterogenous. Cysts with high-risk stigmata or worrisome features are usually resected, depending on the patient's surgical fitness. In patients unfit for resection, newer endoscopic ablative techniques are advocated. Controversial aspects regarding cyst management include whether surveillance can be stopped, how surveillance should be performed, and the extensive financial burden cyst management places on the health care system. Further study into the natural history of cystic lesions, including definitive determination of the rate of malignant transformation for each cyst type, is essential.

[Challenges of cytopathological pancreas diagnostics]

The cytologic diagnostics of solid and cystic pancreatic lesions with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an integral part of the clinical workup and the decision of a surgical versus a conservative approach. Cystic lesions are increasingly being diagnosed due to improved imaging and represent numerous neoplastic as well as non-neoplastic epithelial and non-epithelial entities, which differ in biological behavior and prognosis. In particular, the differentiation of mucinous and non-mucinous cysts is significant for further clinical management. Regressive cellular changes, gastrointestinal contaminants, and overlapping morphologic changes of reactively altered ductal epithelial cells and cells of well-differentiated neoplasms and preneoplasms are special challenges of cytological diagnostics. For a uniform cytological classification of findings, an internationally developed seven-level classification system has been published and co-published by the World Health Organization (WHO). This classification system takes into account both morphological findings and further procedures on cytological material such as next-generation sequencing and immunocytochemistry and is based on the WHO classification for pancreatic tumors. Against this background, important cytologic diagnostic criteria of various solid and cystic lesions relevant in clinical practice are presented in this article, considering diagnostic possibilities and pitfalls as well as differential diagnoses.

Expression of oncogenic HRAS G12V causes defects in control of cell size in NIH 3T3 cells

Severe defects in control of cell size are closely associated with cancer. However, the mechanisms that drive cell size defects in cancer remain unknown and it is unclear whether they are a direct consequence of signals from primary oncogenic drivers or a secondary consequence of mutations that accumulate during evolution of cancer cells. Here, we report that expression of oncogenic HRAS G12V is sufficient to cause cell size defects in NIH 3T3 cells, which suggests that the cell size defects of cancer cells are a direct consequence of primary oncogenic drivers.

Comprehensive characterisation of acinar cystic transformation of the pancreas: a systematic review

AIMS

Acinar cystic transformation (ACT) of the pancreas is a rare pancreatic cystic lesion. Owing to its rarity, comprehensive histomolecular characterisation of this entity is still lacking. We aim to perform a systematic review on this controversial entity.

METHODS

We searched PubMed, SCOPUS and Embase through May 2023 to identify all studies on ACTs. Clinicopathological, immunohistochemical (IHC) and molecular data have been extracted and analysed.

RESULTS

Overall, there were 121 cases of ACTs in the literature. ACT had a female predominance (65.3% of patients), and a mean size of 4.8 cm. ACT was more often unifocal (71.9%) and multiloculate (61.2%). Histologically, the cysts were lined by an acinar epithelium, sometimes harbouring ductal-like areas (18.2%). In five cases (4.1%), an intralesional pancreatic intraepithelial neoplasia (PanIN) was reported. Preoperative diagnosis is challenging. After surgical resection, all patients were alive and disease free during follow-up except one patient who developed a second ACT after resection. By IHC, all lesions were positive for acinar markers; cytokeratin 7 and 8/18/19 were usually positive, and Ki-67 was invariably ≤3%. At the molecular level, three cases demonstrated genetic alterations: one showed multiple chromosomal gains, and other two harboured somatic mutations of KRAS and SMO genes (one mutation per case).

CONCLUSIONS

Globally considered, our findings demonstrated that ACT is a benign entity, without the need of surgical resection with the exception of symptomatic lesions. The rare occurrence of intracystic PanINs and driver mutations suggest considering follow-up if a preoperative diagnosis of ACT can be made.

Systematic review of challenging issues in pathology of intraductal papillary mucinous neoplasms

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are a cystic precursor to pancreatic cancer. IPMNs deemed clinically to be at high-risk for malignant progression are frequently treated with surgical resection, and pathological examination of the pancreatectomy specimen is a key component of the clinical care of IPMN patients.

METHODS

Systematic literature reviews were conducted around eight topics of clinical relevance in the examination of pathological specimens in patients undergoing resection of IPMN.

RESULTS

This review provides updated perspectives on morphological subtyping of IPMNs, classification of intraductal oncocytic papillary neoplasms, nomenclature for high-grade dysplasia, assessment of T stage, distinction of carcinoma associated or concomitant with IPMN, role of molecular assessment of IPMN tissue, role of intraoperative assessment by frozen section, and preoperative evaluation of cyst fluid cytology.

CONCLUSIONS

This analysis provides the foundation for data-driven approaches to several challenging issues in the pathology of IPMNs.

Hyperactive Ras disrupts cell size control and a key step in cell cycle entry in budding yeast

Severe defects in cell size are a nearly universal feature of cancer cells. However, the underlying causes are unknown. A previous study suggested that a hyperactive mutant of yeast Ras (ras2G19V) that is analogous to the human Ras oncogene causes cell size defects, which could provide clues to how oncogenes influence cell size. However, the mechanisms by which ras2G19V influences cell size are unknown. Here, we found that ras2G19V inhibits a critical step in cell cycle entry, in which an early G1 phase cyclin induces transcription of late G1 phase cyclins. Thus, ras2G19V drives overexpression of the early G1 phase cyclin Cln3, yet Cln3 fails to induce normal transcription of late G1 phase cyclins, leading to delayed cell cycle entry and increased cell size. ras2G19V influences transcription of late G1 phase cyclins via a poorly understood step in which Cln3 inactivates the Whi5 transcriptional repressor. Previous studies found that yeast Ras relays signals via protein kinase A (PKA); however, ras2G19V appears to influence late G1 phase cyclin expression via novel PKA-independent signaling mechanisms. Together, the data define new mechanisms by which hyperactive Ras influences cell cycle entry and cell size in yeast. Hyperactive Ras also influences expression of G1 phase cyclins in mammalian cells, but the mechanisms remain unclear. Further analysis of Ras signaling in yeast could lead to discovery of new mechanisms by which Ras family members control expression of G1 phase cyclins.

A brief review of the WHO reporting system for pancreaticobiliary cytopathology

The World Health Organization (WHO), the International Academy of Cytology, and the International Agency for Research on Cancer have developed an approach to standardized reporting of pancreaticobiliary cytopathology. The WHO Reporting System for Pancreaticobiliary Cytopathology (WHO System) revises the Papanicolaou Society of Cytopathology (PSC) System for Reporting Pancreaticobiliary Cytology published in 2015 and replaces the 6 PSC categories with 7 categories: "Insufficient/Inadequate/Nondiagnostic"; "Benign/Negative for malignancy"; "Atypical"; "Pancreaticobiliary neoplasm, low risk/grade (PaN-low)"; "Pancreatic neoplasm, high risk/grade (PaN-High)"; "Suspicious for malignancy"; and "Malignant". In the PSC system, there is a single category for "Neoplastic" lesions that includes 2 groups, 1 for benign neoplasms and 1 named "Neoplastic-other", dominated by premalignant intraductal neoplasms primarily intraductal papillary mucinous neoplasms and low-grade malignant neoplasms (pancreatic neuroendocrine tumors (PanNET) and solid pseudopapillary neoplasms (SPN). In the WHO System, benign neoplasms with virtually no risk of malignancy are included in the "Benign" category and low-grade malignancies (PanNET and SPN) are included in the "Malignant" category, as per the 5th edition of the WHO Classification of Digestive System Tumors, while the non-invasive pre-malignant lesions of the ducts are divided by the cytomorphological grade of the epithelium into PaN-low and PaN-high with distinctly different risks of malignancy. Within each category, key diagnostic cytopathologic features and the ancillary studies for diagnostic and prognostic evaluation, as well as the implications of diagnosis for patient care and management, are outlined. Reporting and diagnostic management options recognize the variations in the availability of diagnostic and prognostic ancillary testing modalities in low- and middle-income countries.

Diagnostic features of low- and high-grade mucinous neoplasms in pancreatic cyst FNA cytology

BACKGROUND

Pancreatic cyst cytology evaluates for neoplastic mucin and epithelial grade. This study describes cytological features of low- and high-grade mucinous neoplasms (MNs) using gastrointestinal contaminants for comparison.

METHODS

Histologically confirmed pancreatic cystic neoplasms were reviewed by a panel of cytopathologists to identify which, among 26 selected cytologic features, correlate significantly with low- and high-grade MN. A test for greater than or equal to four of eight high-grade features (three-dimensional architecture, high nuclear:cytoplasmic ratio, moderate nuclear membrane abnormalities, loss of nuclear polarity, hyperchromasia, >4:1 nuclear size variation in one cluster, karyorrhexis, and necrosis) was assessed for identifying a high-grade neoplasms. Additional characteristics of the cohort such as cyst fluid carcinoembryonic antigen results, molecular testing, Papanicolaou Society of Cytopathology classification, and select high-risk clinical features are described.

RESULTS

Endoscopic ultrasound fine-needle aspirations from 134 MN and 17 serous cystadenomas containing gastrointestinal contaminants were included. The MN consisted of 112 (84%) intraductal papillary MNs (low-grade = 69, 62%; high-grade = 24, 21%; and invasive = 19, 17%) and mucinous cystic neoplasms (low-grade = 20, 90%; high-grade = 2, 10%). Half had greater than five clusters of epithelium for analysis. Compared with gastrointestinal contaminants, mucin from MN was thick and colloid-like (40% vs. 6%, p < .01), covered >20% of the smear area (32% vs. none, p < .01), and contained histiocytes (46% vs. 18%, p = .04). Greater than or equal to four of eight select high-grade features was present in 36% of high-grade MN with sensitivity 37% and 98% specificity.

CONCLUSION

Colloid-like features, >20% of smear, and histiocytes correlated with MN. Testing for greater than or equal to four high-grade features had low sensitivity and high specificity for high-grade MN.

[Diagnostics and clinical management of premalignant diseases of the pancreas]

Pancreatic cancer is one of the most aggressive solid tumors and still has a poor prognosis. A delayed diagnosis at advanced stages and a poor response to systemic treatment frequently make a curative treatment impossible. Therefore, the identification of high-risk patients and screening them regularly is the most promising approach to improve the prognosis. Chronic pancreatitis as well as neoplastic pancreatic cysts can greatly increase the risk of developing pancreatic cancer. Furthermore, familial syndromes and germline mutations also confer an increased risk for development of pancreatic cancer. This article provides an overview of the various premalignant diseases of the pancreas. The value of the various imaging modalities, such as magnetic resonance imaging and endosonography are particularly discussed as well as the screening interval and the indications for surgical treatment are explained.

Diagnostic Performance of Pancreatic Cytology with the Papanicolaou Society of Cytopathology System: A Systematic Review, before Shifting into the Upcoming WHO International System

The Papanicolaou Society of Cytopathology (PSC) reporting system classifies pancreatobiliary samples into six categories (I–VI), providing guidance for personalized management. As the World Health Organization (WHO) has been preparing an updated reporting system for pancreatobiliary cytopathology, this systematic review aimed to evaluate the risk of malignancy (ROM) of each PSC category, also the sensitivity and specificity of pancreatic FNA cytology using the current PSC system. Five databases were investigated with a predefined search algorithm. Inclusion and exclusion criteria were applied to select the eligible studies for subsequent data extraction. A study quality assessment was also performed. Eight studies were included in the qualitative analysis. The ROM of the PSC categories I, II, III, IV, V, VI were in the ranges of 8–50%, 0–40%, 28–100%, 0–31%, 82–100%, and 97–100%, respectively. Notably, the ROM IVB (“neoplastic—benign”) subcategory showed a 0% ROM. Four of the included studies reported separately the ROMs for the IVO subcategory (“neoplastic—other”; its overall ROM ranged from 0 to 34%) with low (LGA) and high-grade atypia (HGA). ROM for LGA ranged from 4.3 to 19%, whereas ROM for HGA from 64 to 95.2%. When the subcategory IVO with HGA was considered as cytologically positive, together with the categories V and VI, there was a higher sensitivity of pancreatic cytology, at minimal expense of the specificity. Evidence suggests the proposed WHO international system changes—shifting the IVB entities into the “benign/negative for malignancy” category and establishing two new categories, the “pancreatic neoplasm, low-risk/grade” and “pancreatic neoplasm, high-risk/grade”—could stratify pancreatic neoplasms more effectively than the current PSC system.

Cytologic Categorization with Risk Stratification of Endoscopic Ultrasound-Guided Fine Needle Aspiration from Pancreatic Lesions Based on Guidelines of the Papanicolaou Society of Cytopathology: 12-Year Tertiary Care Experience

BACKGROUND AND AIMS: Pancreatic malignancy is an important cause of cancer mortality worldwide. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) plays a crucial role in the pre-operative diagnosis of pancreatic lesions. In this study, we have analyzed the cytological spectrum of pancreatic lesions in the Indian population over 12 years, categorized them according to the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSCPC), and assessed the risk of malignancy (ROM) for each of the categories. METHODS: A computerized data search from January 2008 to December 2019 revealed 581 pancreatic EUS-FNA samples, among which surgical follow-up was available for 73 cases. All cytological specimens were reviewed and prospectively classified into one of the six diagnostic categories proposed by the PSCPC. Subsequently, a cytohistological correlation was performed and the ROM was calculated for each category. RESULTS: The cytologic diagnoses included 50 nondiagnostic (category I), 175 negative for malignancy (category II), 19 atypical (category III), 27 neoplastic:benign (category IVA), 30 neoplastic:other (category IVB), 26 suspicious (category V), and 254 malignant (category VI) cases. ROM for non-diagnostic aspirates, nonneoplastic benign specimens, atypical cases, neoplastic:benign, neoplastic:other, suspicious for malignancy, and the malignant category was 16.7%, 7.1%, 33.3%, 0.0%, 20.0%, 100%, and 78.6%, respectively. CONCLUSION: We document an increased risk of malignancy from category I to category VI of the PSCPC. The malignancy risk for category VI (malignant) was statistically significant in our study but was lower in comparison to the values reported by other authors. Nonetheless, such an approach would establish transparent communication between the pathologist and the clinician, as well as aid the clinician in decision making, particularly in intermediate categories.

Cytological Scoring for Pancreatic Specimens Obtained by Endoscopic Ultrasound-Guided Fine Needle Aspiration

OBJECTIVE

Cytological diagnosis of pancreatic specimens obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is often challenging because of the small sample size or well-differentiated adenocarcinoma with weak cytological atypia. Therefore, the sensitivity and specificity of cytological diagnosis for pancreatic cancer should be improved. Hence, we aimed to clarify the utility of cytological scoring to distinguish malignant from benign lesions for the cytological diagnosis of pancreatic EUS-FNA specimens.

METHODS

Seven reviewers, including four cytotechnologists and three medical doctors, evaluated 20 morphological indices in pancreatic specimens obtained by EUS-FNA (malignant, n=111, benign, n=31). Statistical analyses were performed using Fisher's exact test, logistic regression analysis, the area under the receiver operating characteristic curve, and Youden index.

RESULTS

Among the 20 indices, there was a high incidence rate (> 40%) of the following 13 indices in malignant cases: irregular structure, hyperchromatic nucleus, irregular cell polarity, unclear cell boundaries, nuclear membrane thickening, anisonucleosis, overlapping, irregular nuclei, high nuclear/cytoplasmic ratio, binding decline, the simultaneous appearance of malignant and benign cells, enlarged nucleoli, and background necrosis. When we diagnosed pancreatic specimens using these 13 cytological indices, the cutoff value of 8/9 showed the highest Youden index (0.950) as well as high sensitivity and specificity in distinguishing malignant from benign specimens (98% and 97%, respectively).

CONCLUSION

Thirteen cytological indices showed high sensitivity and specificity in differentiating malignant and benign lesions using pancreatic EUS-FNA samples. All 13 indices were important for diagnosing malignancy in the pancreatic cytology smear of EUS-FNA. Further validation studies are required.

Intraductal papillary mucinous neoplasm of the pancreas: Cytomorphology, imaging, molecular profile, and prognosis

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) constitutes up to 20% of all pancreatic resections, and has been increasing in recent years. Histomorphological findings of IPMN are well established; however, there are not many published papers regarding the cytological findings of IPMN on fine needle aspiration (FNA) specimens. We review the cytomorphological features, molecular profile, imaging findings, and prognosis of IPMN.

METHODS

The English literature was thoroughly searched with key phrases containing IPMN.

OBSERVATIONS

IPMN is a rare entity, affecting men and women equally and is usually diagnosed at the age of 60-70 years. The characteristic imaging features include a cystic lesion with associated dilatation of the main or branch pancreatic duct, and atrophy of surrounding pancreatic parenchyma. Cytomorphological features of IPMN include papillary fragments of mucinous epithelium in a background of abundant thick extracellular mucin, a hallmark feature. IPMNs should be evaluated for high-grade dysplasia, which manifests with nuclear atypia, nuclear moulding, prominent nucleoli, nuclear irregularity, and cellular crowding. Molecular profiling of IPMN along with carcinoembryonic antigen and amylase levels is useful in predicting malignancy or high-grade dysplasia arising in IPMN. Overall, the prognosis of IPMN is excellent except in those cases with high-grade dysplasia and malignant transformation. Postoperative surveillance is required for resected IPMNs.

CONCLUSION

IPMN requires a multidisciplinary approach for management. Cytomorphological findings of IPMN on FNA, in conjunction with tumour markers in pancreatic fluid cytology and imaging findings, are of paramount importance in clinical decision-making for IPMN.

Endoscopic Ultrasound-Guided Fine Needle Aspiration Cytologic Evaluation of Intraductal Papillary Mucinous Neoplasm and Mucinous Cystic Neoplasms of Pancreas

OBJECTIVES

To evaluate the role of endoscopic ultrasound-guided fine needle aspiration cytology in identifying mucinous cystic lesions (MCLs) in histologically proven cases of intraductal papillary mucinous neoplasm (IPMN) or mucinous cystic neoplasm (MCN) and risk of malignancy associated with each cytologic category based on the Papanicolaou Society of Cytopathology (PSC) guidelines.

METHODS

All resected cases with histologic diagnosis of IPMN or MCN at our institution from January 1, 2004, to August 31, 2019, with associated cytology were included. Available cytology slides of nondiagnostic (ND), negative/benign (BN), and atypical cytology (AC) cases were reviewed and reclassified based on the PSC guidelines.

RESULTS

A total of 120 cases were identified, including 57 IPMNs with low-grade or moderate dysplasia (LGD/MD) and high-grade dysplasia (HGD), 34 MCNs with LGD/MD or HGD, and 29 IPMNs with invasive malignancy. After cytology slide review and reclassification, we observed that ND and BN cases were paucicellular and lacked ancillary testing (carcinoembryonic antigen levels or KRAS mutation analysis). The risk-of-malignancy rates were 33% for ND, 11% for BN, 28.5% for AC, 17% for MCL, and 100% for suspicious/positive cytologic diagnosis.

CONCLUSIONS

A multidisciplinary approach including combined use of cytology and ancillary testing is helpful in establishing a diagnosis of MCL and identifying associated malignancy.

Validation of the clinical utility of 4 guidelines in the initial triage of mucinous cystic lesions of the pancreas based on cross-sectional imaging: Experience with 188 surgically-treated patients

INTRODUCTION

Over the years, several guidelines have been introduced to guide management of mucinous pancreatic cystic neoplasms (mPCN). In this study, we aimed to evaluate and compare the clinically utility of the Sendai-06, Fukuoka-12, Fukuoka-17 and European-18 guidelines in predicting malignancy of mPCN.

METHODS

One hundred and eighty-eight patients with mucinous cystic neoplasms (MCN) or intraductal papillary mucinous neoplasm (IPMN) who underwent surgery were retrospectively reviewed and classified under the 4 guidelines. Malignancy was defined as high grade dysplasia and invasive carcinoma.

RESULTS

Raised CA19-9>37U/ml, enhancing mural nodule≥5 mm and main pancreatic duct≥10 mm were significantly associated with malignancy on multivariate analysis. Increasing number of high risk features, absolute indications (European-18), worrisome risk or relative indications (European-18) were significantly associated with an increased likelihood of malignancy. The positive predictive values (PPV) of high risk features for Sendai-06, Fukuoka-12, Fukuoka-17 and absolute indications (European-18) for malignancy were 53%, 76%, 78% and 78% respectively. The negative predictive values (NPV) of the Sendai-06, Fukuoka-12 and Fukuoka-17 were 100%, while that of the European-18 was 92%. Risk of malignancy for patients with ≥4 worrisome features (Fukuoka-17) and ≥3 relative indications (European-18) was 66.7% and 75.0% respectively.

CONCLUSIONS

All 4 guidelines studied were useful in the initial triage of mPCN for the risk stratification of malignancy. The Fukuoka-17 had the highest PPV and NPV.

Experience and future perspectives on the use of the Papanicolaou Society of Cytopathology Terminology System for reporting pancreaticobiliary cytology

The Papanicolaou Society of Cytopathology developed a set of guidelines for reporting pancreaticobiliary cytology in 2014 (PB System), with a six-tiered system: Nondiagnostic, Negative, Atypical, Neoplastic (Benign or Other), Suspicious, and Positive. This proposed scheme incorporates ancillary testing such as biochemical testing of cyst fluids for diagnosis and provides terminology that standardizes the category of the various diseases of the pancreas, some of which are difficult to diagnose specifically by cytology alone. Since its initial publication five and half years ago, several groups have published their experiences on the use of the PB System and have shown that most objectives proposed by the original publication have been achieved. They have shown that there is a better understanding and definition of the diagnostic categories with an associated distribution and risk of malignancy. The diagnostic categories of Neoplastic: Other, Suspicious, and Malignant show a high sensitivity and specificity for the diagnosis of malignancy. The System also provides a multi-specialist view of pancreatic lesions, with biochemical and radiological findings being incorporated into the final pathological report. The present review summarizes these findings and discusses the future perspectives and foreseen changes that are to be incorporated to a second edition of the reporting System.

Diagnosis and management of pancreatic cystic neoplasms: current evidence and guidelines

Pancreatic cystic neoplasms (PCN) are a heterogeneous group of pancreatic cysts that include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms and other rare cystic lesions, all with different biological behaviours and variable risk of progression to malignancy. As more pancreatic cysts are incidentally discovered on routine cross-sectional imaging, optimal surveillance for patients with PCN is becoming an increasingly common clinical problem, highlighting the need to balance cancer prevention with the risk of (surgical) overtreatment. This Review summarizes the latest developments in the diagnosis and management of PCN, including the quality of available evidence. Also discussed are the most important differences between the PCN guidelines from the American Gastroenterological Association, the International Association of Pancreatology and the European Study Group on Cystic Tumours of the Pancreas, including diagnostic and follow-up strategies and indications for surgery. Finally, new developments in the management of patients with PCN are addressed.

Risk of malignancy in the categories of the Papanicolaou Society of Cytopathology system for reporting pancreaticobiliary cytology

BACKGROUND

Management of pancreatic lesions depends on the risk of malignancy, which is primarily determined from the cytologic and radiologic evaluation findings. The Papanicolaou Society of Cytopathology (PSC) published a classification system for reporting pancreaticobiliary cytology. However, the "neoplastic: other" category can be further stratified by high-grade atypia (HGA). Studies on the risk of malignancy using the PSC system have been limited.

MATERIALS AND METHODS

All patients who had undergone endoscopic ultrasound-guided fine-needle aspiration (FNA) for a pancreatic lesion at Massachusetts General Hospital from January 2016 to December 2016 were prospectively classified. The clinical, radiographic, and endoscopic findings, cytologic and histologic diagnoses, and follow-up data from 334 FNA biopsies from 322 patients were reviewed. The neoplastic: other category was subclassified as low-grade atypia or HGA. The absolute risk of malignancy was determined by the histologic outcome or follow-up of ≥6 months.

RESULTS

The absolute risk of malignancy was 7.7% for the nondiagnostic category; 1.0% for negative; 28.0% for atypical; 0.0% for neoplastic: benign; 30.3% for neoplastic: other; 90.0% for neoplastic: other with HGA; 100% for suspicious; and 100% for positive. When the neoplastic: other with HGA, suspicious, and positive cytologic diagnoses were considered positive, the sensitivity, specificity, positive predictive value, and negative predictive value for pancreatic FNA biopsy was 92.2%, 98.8%, 98.3%, and 94.3%, respectively.

CONCLUSIONS

Categories of the PSC system each carry an implied absolute risk of malignancy, increasing from the negative to positive categories. The presence of HGA identifies lesions at the greatest risk of malignancy in the neoplastic: other category, and its inclusion with suspicious and positive as positive diagnoses optimizes the diagnostic performance of identifying high-risk lesions that warrant surgical excision.