Observations on the application of the Papanicolaou Society of Cytopathology standardised terminology and nomenclature for pancreaticobiliary cytology

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.

Efficacy of endoscopic samplings during initial biliary drainage for cases of pancreatic head cancer: United diagnostic yields of multiple pathological samplings

BACKGROUND/OBJECTIVES

The diagnostic ability of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been fully studied; however, the efficacy of other endoscopic samplings (OESs) is less clear. The aim of this study was to examine the diagnostic efficacies of OESs for pancreatic head cancer (PHC).

METHODS

The diagnostic efficacies of endoscopic samplings were retrospectively analyzed in 448 PHC cases and 63 cases of mass-forming pancreatitis (MFP) during initial transpapillary biliary drainage. The OESs included duodenal biopsy (118 PHCs and 50 MFPs), biliary biopsy (218 and 51) with cytology (368 and 53), and pancreatic duct biopsy (23 and 13) with cytology (56 and 43). EUS-FNA was conducted in a different session (149 and 62). Factors associated with OES sensitivity were analyzed. The sensitivity of biliary biopsy was compared between 1.95 mm and 1.8 mm forceps.

RESULTS

Cancer cells were confirmed in 87.9% of the EUS-FNA samplings and in 64.1% (268/418) obtained by combined OESs (average 1.7 OES types per case): 68.6% by duodenal biopsy, 59.6% by biliary biopsy, 32.6% by biliary cytology, 73.9% by pancreatic duct biopsy, and 33.9% by pancreatic duct cytology. No MFP cases revealed cancer by any sampling. OESs did not increase adverse events. Duodenal stenosis, serum bilirubin, tumor size, and pancreatic juice amounts were associated with OES sensitivity. Biliary biopsy had the same sensitivity with different forceps.

CONCLUSION

EUS-FNA was the most diagnostic protocol; however, OESs can be safely applied during the initial biliary drainage to reduce the demand for EUS-FNA while providing good diagnostic yields.

Risk of malignancy associated with diagnostic categories of the proposed World Health Organization International System for Reporting Pancreaticobiliary Cytopathology

BACKGROUND

The World Health Organization (WHO) has proposed an updated international classification system for reporting pancreaticobiliary cytology. Substantial changes to the prior Papanicolaou Society of Cytopathology (PSC) system have been recommended. Chiefly, the "neoplastic: benign" and "neoplastic: other" categories have been replaced by 2 new categories-"pancreatic neoplasia-low-grade" (PaN-Low) and "pancreatic neoplasia-high-grade" (PaN-High)-stratifying neoplastic mucinous cysts by cytological atypia. Low-grade malignancies are placed in the "malignant" category and benign serous cystadenoma in the "benign/negative" category. Risk of malignancy (ROM) associated with the diagnostic categories of the WHO system has yet to be defined.

METHODS

All patients who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for a pancreatic lesion at a single institution from January 2016 to December 2016, prospectively classified using the PSC system, were reclassified using the WHO system. Absolute ROM was determined by histologic outcome and/or clinical follow-up of at least 6 months.

RESULTS

A total of 334 EUS-FNA samples from 322 patients were reviewed and reclassified. Absolute ROM for the WHO system was 7.7% for "insufficient/inadequate/nondiagnostic" category, 1.0% for "benign/negative for malignancy," 28.0% for "atypical," 4.8% for "PaN-Low," 60.0% for "PaN-High," 100% for "suspicious for malignancy," and 100% for "malignant;" the absolute ROM for the same cohort using the PSC system was 7.7% for "nondiagnostic" category, 1.0% for "negative (for malignancy)," 28.0% for "atypical," 0.0% for "neoplastic: benign," 30.3% for "neoplastic: other," 100% for "suspicious (for malignancy)," and 100% for "positive or malignant."

CONCLUSIONS

The WHO international system achieves improved stratification by associated ROM compared to the PSC system.

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%.

A review of medical terminology standards and structured reporting

Much effort has been invested in standardizing medical terminology for representation of medical knowledge, storage in electronic medical records, retrieval, reuse for evidence-based decision making, and for efficient messaging between users. We only focus on those efforts related to the representation of clinical medical knowledge required for capturing diagnoses and findings from a wide range of general to specialty clinical perspectives (e.g., internists to pathologists). Standardized medical terminology and the usage of structured reporting have been shown to improve the usage of medical information in secondary activities, such as research, public health, and case studies. The impact of standardization and structured reporting is not limited to secondary activities; standardization has been shown to have a direct impact on patient healthcare.