Cytologic categorization of pancreatic neoplastic mucinous cysts with an assessment of the risk of malignancy: A retrospective study based on the Papanicolaou Society of Cytopathology guidelines

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.

The WHO system versus the Papanicolaou society of cytopathology system for reporting pancreaticobiliary cytology for risk stratification-which is better?

BACKGROUND

Recently, the World Health Organization (WHO) has proposed a reporting system for pancreaticobiliary cytopathology. We applied this classification for pancreatic lesion samples by fine needle aspiration (FNA) and compared the results to the previous classification of the Papanicolaou Society of Cytopathology (PSC) system for risk stratification.

METHODS

The computerized database was searched for all pancreatic endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and transabdominal ultrasound-guided FNA (TUS-FNA) samples from 2016 to 2020 and cases were reassigned as per the PSC and the WHO diagnostic categories. Cases with follow-up, clinicoradiological, and/or histopathology were included in the study. The risk of malignancy (ROM) was calculated across all diagnostic categories based on clinical data, imaging data, and histopathology wherever available.

RESULTS

There were a total of 625 pancreatic FNA. In 230 cases, follow-up information was available which included 116 EUS and 114 TUS-FNA samples. The ROM for PSC categories I-VI was 40%, 19.7%, 28.6%, 57.1%, 94.7%, and 97.9% and for the WHO categories (I-VII), it was 60%, 21.3%, and 35.7%, not representative, not applicable, 94.7% and 94.9%. The overall sensitivity and specificity of PSC was 68.2% and 96.2% when categories V and VI were taken as positive and 78.9% and 93.3% for WHO when categories VI and VII were taken as positive.

CONCLUSIONS

Pancreatic FNA samples reported as per the WHO system showed better sensitivity as compared to the PSC system resulting in better risk stratification and consequently better patient management. The overall high specificity and moderate sensitivity reaffirm the utility of FNA in pancreatic lesions.

The World Health Organization classification of pancreaticobiliary cytopathology stratifies risk of malignancy and outcome for endoscopic ultrasound-guided fine-needle aspiration of the pancreas

BACKGROUND

The World Health Organization (WHO) has recently published a classification for reporting pancreaticobiliary cytopathology with differences compared to the Papanicolaou Society of Cytopathology (PSC) classification.

METHODS

Retrospective data were collected from pancreatic endoscopic ultrasound-guided fine-needle aspirations from 2014 to 2017 at a pancreatic cancer center. Absolute risk of malignancy (AROM), relative risk (to benign), performance characteristics, and overall survival were calculated for the entire cohort with comparison of cysts and solid lesions.

RESULTS

In total, 2562 cases were included: 16% cyst (n = 411) and 84% solid (n = 2151). The histologic confirmation rate was 43% (n = 1101) and the median follow-up (for benign) was 56 months. For WHO I-VII, overall AROM (%) was 23, 22, 62, 13, 65, 97, and 100; cyst AROM was 7, 0, 19, 13, 38, 78, and 100; and solid AROM was 50, 29, 70, 15, 100, 99, and 100. For PSC I-VI, overall AROM (%) was 23, 29, 64, 0 (IVa), 60 (IVb), 97, and 100; cyst AROM was 7, 0, 19, 0, 21, 78, and 100; and solid AROM was 50, 35, 73, 0, 92, 99, and 100. The difference in relative risk for a cyst (vs. solid) overall was 0.38 for WHO and 0.26 for PSC. WHO and PSC categories showed stratification for the probability of overall survival.

CONCLUSIONS

Cystic versus solid lesion type can dramatically affect AROM, particularly for nondiagnostic (I), benign (II), atypical (III), and WHO V categories. WHO IV conveys a similarly low AROM for cystic and solid types. Both classifications stratify the probability of overall survival, including the newly introduced categories WHO IV and WHO V.

Optimal carcinoembryonic antigen (CEA) cutoff values in the diagnosis of neoplastic mucinous pancreatic cysts differ among assays

AIM

Pancreatic cyst fluid carcinoembryonic antigen (CEA) is a pivotal test in the diagnosis and management of neoplastic mucinous cysts (NMC) of the pancreas. Cyst fluid CEA levels of 192 ng/mL have been widely used to identify NMC. However, CEA values are unique to and significantly differ between individual assays with various optimal cutoffs reported in the literature for NMC. Here, we investigate the optimal CEA cut-off value of pancreatic cysts from two different assays to identify differences in thresholds.

METHODS

Pancreatic cyst fluid CEA levels, CEA assay platform (Beckman Dxl (BD) or Siemens Centaur XP (SC)), and clinical/pathological information were retrospectively collected. Cases were categorised into either NMC or non-NMC. Optimal CEA cut-off values were calculated via a receiver operator characteristic curve. Cut-off values were then identified separately by assay platform.

RESULTS

In total, 149 pancreatic cystic lesions with concurrent CEA values (SC: n=47; BD: n=102) were included. Histological correlation was available for 26 (17%) samples. The optimal CEA cut-off value for all samples at the study institution was 45.9 ng/mL (area under the curve (AUC)=86, Sn=85.7%, Sp=73.8%). When analysed separately by CEA assay, the cut-off values were 45.9 ng/mL (AUC=84.27, Sn=89.7%, Sp=71.4%) for BD and 24.4 ng/mL (AUC=77, Sn=81.8%, Sp=75%) for SC (p=0.48).

CONCLUSIONS

This study showed an optimal pancreas cyst CEA cut-off threshold of 45.9 ng/mL, which is lower than commonly cited literature with different cutoffs on the two separate platforms (BD: 45.9 ng/mL, SC: 24.4 ng/mL).

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.

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.

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.

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.

Risk of malignancy associated with the diagnostic categories proposed by the Papanicolaou Society of Cytopathology for pancreaticobiliary specimens: An institutional experience

BACKGROUND

The guidelines published by the Papanicolaou Society of Cytopathology (PSC) intend to unify the reporting language in pancreaticobiliary specimens and improve communication between cytopathologists and clinicians. The six categories in the system will determine the best management for patients. However, there is limited evidence regarding the risk of malignancy (ROM) associated with each category.

METHODS

A retrospective search was performed for pancreaticobiliary fine-needle aspiration (FNA) reports with corresponding surgical follow-up. Cases were reclassified according to the PSC. The ROM, sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each category.

RESULTS

A total of 297 cases were identified and reclassified as: 30 nondiagnostic (category I), 45 negative for malignancy (II), 20 atypical (III), 42 neoplastic: other (IVB), 19 suspicious for malignancy (V), and 141 malignant (VI). The absolute ROM was 10% for category I, 8.9% for category II, 60% for category III, 4.8% for category IV when the neoplasms were not characterized as malignant, and 100% when categorized as malignant; 100% for category V, and 95.7% for category VI. Sensitivity, specificity, positive predictive value, and negative predictive value for neoplasia and malignancy, including categories IV to VI, were 96.6%, 88.4%, 97.5%, and 84.4%, respectively.

CONCLUSIONS

The categories developed by the PSC stratify the ROM. Aspirates designated as categories V and VI had the highest ROM. Our rate of atypical category complies with the recommended rate of <10%. This scheme provides valuable information to clinicians treating patients with pancreatic lesions.

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.

Diagnostic sensitivity and risk of malignancy for bile duct brushings categorized by the Papanicolaou Society of Cytopathology System for reporting pancreaticobiliary cytopathology

BACKGROUND

The Papanicolaou Society of cytopathology developed a six-category system for pancreaticobiliary cytology specimens. Each category is associated with a definition, diagnostic criteria, estimated risk of malignancy and management recommendations. Risks of malignancy are well defined for specimens obtained by fine-needle aspiration but are less well defined for brushing specimens.

METHODS

Diagnoses of 232 brushing specimens of the pancreatic and bile ducts were correlated with diagnoses from subsequent surgical or cytologic specimens. Sensitivity for the brushing technique was calculated. Risk of malignancy was calculated for each category using the original definitions for nondiagnostic and negative categories and for those of a modified system.

RESULTS

Diagnostic sensitivity was 60%-64%. Risk of malignancy for the nondiagnostic, negative, atypical, suspicious for malignancy, and malignant categories was 28%, 28%, 61%, 91%, and 91%, respectively, when the original category definitions were used.

CONCLUSIONS

Diagnostic sensitivity for duct brushings is low in comparison to fine-needle aspiration. Risk of malignancy is comparable to that of needle aspiration for the negative, atypical and suspicious categories but lower for the malignant category. There is a stepwise increase in malignancy risk as one moves from the negative to the atypical to the suspicious for malignancy categories.

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.

Pathology of intraductal papillary mucinous neoplasms

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) represent a unique opportunity to treat and prevent a curable neoplasm before it has the chance to progress to incurable cancer. This prospect, however, has to be balanced with the real risk of over treating patients with lesions that would, in fact, never progress during the life of the patient.

PURPOSE

Informed clinical decisions in the treatment of IPMNs are first and foremost based on a deep understanding of the pathology of these lesions.

CONCLUSIONS

Here we review the pathology of IPMNs, with an emphasis on the clinical relevance of the important features that characterize these lesions.

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.

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.

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.

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.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.