The impact of the new proposed Papanicolaou Society of Cytopathology terminology for pancreaticobiliary cytology in endoscopic US-FNA: A single-Institutional experience

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.

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.

Classification of endoscopic ultrasound guided fine needle aspiration cytology of pancreatic space occupying lesions by Papanicolaou Society of Cytopathology System: A five year study

BACKGROUND

Majority of the pancreatic cancer patients present at an advanced stage and have poor 5 year survival rate. Thus, there is a need for early detection of pancreatic cancer with the initiation of the therapy.

MATERIALS & METHODS

This is a retrospective study including all the endoscopic ultrasound guided (EUS) guided pancreatic FNAs from 2016 to 2020. The aspirate smears were analyzed and classified according to The Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSCPC).

RESULTS

A total of 245 EUS guided FNAs from pancreatic lesions were included. Cyto-histological correlation was done wherever available. Category I (non diagnostic) accounted for 40 cases (16%) cases, Category II (negative) comprised of 44 cases (18%); and Category III (Atypical) had 5 cases (2%). Category IV neoplastic-benign category included 3 cases of serous cystadenoma, while neoplastic-others category included pancreatic neuroendocrine tumors (n = 21), solid pseudo-papillary neoplasms (SPEN) (n = 12) and mucinous cystic neoplasms (n = 4). A total of 7 cases (2.8%) were reported in Category V (Suspicious). A diagnosis of adenocarcinoma (Category VI) was rendered in 105 cases (42.8%) cases. Rarer types included non Hodgkins lymphoma (n = 3) and one case of primary undifferentiated carcinoma with osteoclastic giant cells. Cyto-histological correlation in all categories was available in 58 cases with 8 false negative cases. Thus overall sensitivity of EUS guided FNAC was found to be 87.8% with a diagnostic yield of 83.6% while sensitivity in diagnosing adenocarcinoma was 96.9%.

CONCLUSION

The present study highlights the spectrum of EUS guided FNA of pancreatic lesions in a subset of North Indian population and classified them according to PSCPC. EUS guided FNAC is a sensitive investigation which plays a crucial role in confirming the diagnosis of pancreatic space occupying lesions (SOLs) in advanced stage.

The Role Of Cytology In The Investigation And Management Of Pancreatobiliary Lesions With A Transition Towards A Standardised Reporting System: An Institutional Perspective

Pancreatobiliary pathology encompasses all benign and malignant disease within the pancreas and biliary tract; pancreatic cancer is currently the seventh leading cause of death worldwide accounting for approximately 466,000 deaths per annum. Cytology has been increasingly used in the physician's toolbox to provide an accurate, non-invasive and cost-effective modality for the diagnosis of pancreatobiliary lesions. The cytological appearance alone may be insufficient to establish the diagnosis and it is crucial for effective clinicopathological correlation in a multidisciplinary setting highlighting, the vital role of the pathologist to ensure effective and quality care. The advent of modern diagnostic techniques has allowed for a less invasive approach to tissue sampling which when combined with routine staining and specialised immunohistochemistry can help guide the diagnosis. The Papanicolaou Classification is comparable to the current C1-C5 system which will enable standardised reporting to help to improve communication with clinical colleagues and subsequent patient management and our article will discuss the criteria used by cytopathologists to determine the grade of both pancreatic and biliary lesions.

Atypical cells in fine needle aspiration biopsies of pancreas: Causes, work-up, and recommendations for management

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a sensitive and specific method for diagnosing cancer in solid pancreatic masses. However, some cases receive indeterminate atypical diagnoses, which creates management dilemmas. In the 2014 Papanicolaou Society of Cytopathology (PSC) standardized guidelines for pancreatobiliary cytology, specimens in the "Atypical" category show a spectrum of architectural and/or cellular changes beyond normal or reactive, but, quantitatively or qualitatively, insufficient for classification as neoplastic (benign/other), suspicious or positive for malignancy. Implementation of the PSC system decreased atypical diagnoses, particularly for cystic lesions, and redistributed many cases into benign and neoplastic categories. Because no set cytologic criteria exist for the "Atypical" category there is wide variability in its use, and its frequency ranges from 0%-16% (mean 6%). It consists of a heterogeneous mix of cases that occur because of preanalytic, lesion-specific (low cellularity, necrosis, cystic, reactive and premalignant changes), to pathologist-dependent factors (experience, expertise, training and institutional case volume). Outcomes of atypical diagnoses in solid pancreatic masses range from benign to premalignant and malignant and include reactive atypia in pancreatitis, well differentiated adenocarcinoma, and non-ductal malignancies. The associated risk of malignancy (ROM) ranges from 28%-100%, with an overall intermediate ROM in large-scale studies. Cytopathologists and institutions should monitor and keep their personal and/or laboratory's atypical rates low by judiciously using rapid onsite evaluation, ancillary studies, consensus or expert review, as well as correlation with clinical and radiologic findings. Early repeat EUS-FNA is indicated for unresolved cases.

The benefits of the Papanicolaou Society of Cytopathology System for reporting pancreatobiliary cytology: A 2-year review from a single academic institution

OBJECTIVE

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is an essential tool in the diagnosis of pancreatic lesions. The aim of this study was to evaluate the diagnostic accuracy of cytology from EUS-FNA, to correlate the results with the corresponding histopathological diagnoses and to analyse the impact of retrospective assignment of the Papanicolaou Society of Cytopathology (PSC) reporting system categories.

METHODS

All pancreatic FNA specimens reported at the Royal Free Hospital during a 2-year period were retrospectively collected and assigned to the PSC system categories. Any available corresponding histological samples were assessed for concordance.

RESULTS

In total, 236 cytology specimens from 223 patients were identified, of which 108 (45.8%) had corresponding histology samples. The main reason for cyto-histological discrepancy was sampling error. Interpretive error was identified in one case. Overall, sensitivity was 92.5%, specificity was 100%, diagnostic accuracy of cytology was 95%, false-positive rate was 0% and false-negative rate was 7.5%. The implementation of the new reporting system reduced the number of cases in the atypical category. All cases previously categorised as suspicious or malignant remained in the same category.

CONCLUSIONS

EUS-FNA is an accurate method for evaluating pancreatobiliary lesions. The implementation of the Papanicolaou Society of Cytopathology diagnostic system enhances standardisation of the reporting terminology and reduces the number of samples in the non-standardised and equivocal atypical category.

The applicability of Papanicolaou Society of Cytopathology system on reporting endoscopic ultrasound-guided fine needle aspiration cytology specimens of pancreatic lesions in situations with limited availability of ancillary tests. Experience at a single laboratory

INTRODUCTION

The Papanicolaou Society of Cytopathology (PSC) system of reporting pancreatobiliary cytology is a standardised reporting nomenclature that uses a six-tiered scheme of diagnostic categories utilising routine microscopy and ancillary tests such as biochemical and molecular analysis of cyst fluids and immunochemistry. The objective of this study was to determine the applicability of the PSC system on endoscopic ultrasound-guided fine needle aspiration cytology samples reported at the cytopathology laboratory, Mubarak Al Kabeer Hospital, in Kuwait with special emphasis on situations with limited availability of ancillary tests.

METHODS

In total, 132 cases of endoscopic ultrasound-guided fine needle aspiration cytology samples from pancreatic lesions were categorised according to PSC system guidelines after examining the glass slides and reviewing the clinical, imaging and ancillary test findings. These review diagnoses were compared with the diagnoses rendered during initial reporting. Correlation with histopathology reports was done wherever available.

RESULTS

In 23 (17.42%) of 132 cases, re-categorisation was necessary between initial and reviewed diagnoses. In 16 cases, re-categorisations were because of non-analogous categories between initial and reviewed diagnosis. In the remaining seven, they were due to identification of newer cytomorphological and imaging findings or because of issues arising from unavailability of sufficient material for ancillary investigations.

CONCLUSION

All cases could be categorised using the PSC system with a moderate number of re-categorisations between initial and reviewed diagnoses. In certain circumstances, limited availability of ancillary tests, resulted in non-diagnostic categories whereas in other such circumstances, diagnostic categories could be assigned with certain conceptual modifications to the PSC guidelines.

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.

Reclassification of lesions in biopsies by fine-needle aspiration of pancreas and biliary tree using Papanicolaou classification

BACKGROUND

Our aim was to evaluate the application of the classification of the Papanicolaou Cytopathology Society for the report of biopsies by fine-needle aspiration (FNA) of pancreas and bile duct.

METHODS

The FNAs obtained consecutively during 1 year were analyzed. Descriptive statistics were performed and sensitivity, specificity, positive predictive value, negative predictive value, and cytohistological correlation were determined. The reference standard test was the histopathological study.

RESULTS

A total of 134 cases of FNA were reclassified with ultrasound guidance according to the classification of the Papanicolaou Society, the median age was 59 years (range, 25-80 years). A case interpreted as non-diagnostic was reclassified to category 4 and 3 cases with atypical cells were reclassified to category 5. All malignant cases remained unchanged. Surgical follow-up was performed in 35 patients (26.1%), with a cytohistological concordance in 21 cases (91.3%) and 2 discordant cases (8.7%), the reasons for the discrepancy were due to sampling error, one of them with scarce material to make a diagnosis of higher category, the other case with partial agreement, because cytology was observed atypical cylindrical epithelium, with histology of grade 2 neuroendocrine neoplasia and low grade mucinous intraepithelial neoplasia. In general, the sensitivity and specificity were 100% and 75% respectively, the positive predictive value 88% and the negative predictive value 100%.

CONCLUSIONS

The FNA guided with endoscopic ultrasound (EUS) and interpreted according to the Papanicolaou Cytopathology Society Classification is an accurate method to evaluate pancreatic and biliary tract lesions with a high positive predictive value of 88%.

Papanicolaou Society of Cytopathology new guidelines have a greater ability of risk stratification for pancreatic endoscopic ultrasound-guided fine-needle aspiration specimens

The Papanicolaou Society of Cytopathology has recently proposed a standardized terminology and nomenclature guidelines for pancreatic cytology. However the risk of malignancy associated with the new guidelines has been scarcely studied. In this study, a series of pancreatic cytology cases obtained by endoscopic ultrasound-guided fine-needle aspiration from 294 Chinese patients were retrospectively re-categorized into six categories according the new guidelines. The risks of malignancy were 18.1% for “negative,” 20.0% for “neoplastic,” 57.1% for “nondiagnostic,” 69.2% for “atypical,” 87.5% for “suspicious,” and 100.0% for “positive” respectively. The area under the receiver operating characteristic curve was 0.93 (95% Confidence Interval, 0.90-0.96), which was significantly higher than that associated with old classification system (0.82; 95% Confidence Interval, 0.77-0.87) conventionally used in China. Our investigation demonstrated that the new guidelines have a greater ability of risk stratification than the old classification system conventionally used in China. This may be helpful in giving better predictions of malignancy, thus leading to more personalized treatment strategies.

Pancreatic Cytopathology

Pancreatic cytopathology, particularly through the use of endoscopic ultrasound-guided fine-needle aspiration (FNA), has excellent specificity and sensitivity for the diagnosis of pancreatic lesions. Such diagnoses can help guide preoperative management of patients, provide prognostic information, and confirm diagnoses in patients who are not surgical candidates. Furthermore, FNA can be used to obtain cyst fluid for ancillary tests that can improve the diagnosis of cystic lesions. In this article, we describe the cytomorphological features and differential diagnoses of the most commonly encountered pancreatic lesions on FNA.

Variation of cytopathologists' use of the indeterminate diagnostic categories "atypical" and "suspicious for malignancy" in the cytologic diagnosis of solid pancreatic lesions on endoscopic ultrasound-guided fine-needle aspirates

Indeterminate cytologic diagnoses in endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNA) of solid pancreatic lesions include the diagnostic categories "atypical" (ATY) and "suspicious for malignancy" (SUSP), which are used at variable rates and are associated with variable underlying risk of malignancy. The aim of this study was to determine individual cytopathologists' rates of indeterminate diagnoses in EUS-FNA of solid pancreatic lesions and their relationship to cytopathologists' experience and volume of pancreatic EUS-FNA examined, as well as the potential impact of departmental consensus review on indeterminate diagnoses.

DESIGN

The diagnostic rates of ATY and SUSP and their underlying risk of malignancy were calculated for six cytopathologists who diagnosed 1,114 of 1,225 EUS-FNA of solid pancreatic lesions from 1/1/2001 to 9/15/2014, and were then compared for the periods before and after the implementation of departmental consensus review during 2009.

RESULTS

The six cytopathologists diagnosed 10% of cases as indeterminate; 82 (7.4%) as "atypical" and 29 (2.6%) as "suspicious". The individual cytopathologists' indeterminate diagnosis rates varied twofold (6.67-12.80%) and did not correlate with their experience, total or annual volume of EUS-FNAs. Of the 56/99 (56.57%) cases with follow-up, the underlying rate of malignancy was 47% (35/75; for "atypical" and 87.5% (21/24); for "suspicious"). The underlying rates of malignancy were 33-67% for "atypical" and 80-100% for "suspicious" diagnoses made by individual cytopathologists. The rate of indeterminate diagnoses decreased from 11.55 to 7.88% after the implementation of departmental consensus review.

CONCLUSION

Individual cytopathologists' rates of indeterminate diagnoses and their significance vary; however, consensus review is helpful in reducing these rates. Diagn. Cytopathol. 2017;45:3-13. © 2016 Wiley Periodicals, Inc.