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.

Use of the Afirma Xpression Atlas for cytologically indeterminate, Afirma Genomic Sequencing Classifier suspicious thyroid nodules: Clinicopathologic analysis with postoperative molecular testing

OBJECTIVES

Afirma has recently introduced its Xpression Atlas (XA) as an adjunct to its Genomic Sequencing Classifier (GSC) for risk stratification of cytologically indeterminate thyroid nodules. We evaluated the performance of Afirma XA and associated pathologic findings for Afirma GSC suspicious nodules.

METHODS

Intradepartmental records of thyroid fine-needle aspirations (FNAs) from January 2021 to December 2022 were identified and reviewed for patient and nodule characteristics, FNA findings, molecular test results, and final surgical pathology, if available.

RESULTS

Material for Afirma GSC testing was collected in 624 thyroid FNAs, and 148 (24%) were classified as cytologically indeterminate. Afirma GSC testing was successful in 132 (89%) of those cases, of which 35 (27%) were Afirma GSC suspicious. Afirma XA testing was positive in 11 cases (11/35 [31%]). Eight (73%) patients underwent surgery that revealed 7 patients with papillary thyroid carcinoma and 1 patient with noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) (risk of malignancy: 100% [8/8]). Among the 24 patients with negative Afirma XA results, 19 (79%) underwent surgery, revealing 5 patients with malignancy and 3 patients with NIFTP (risk of malignancy: 42% [8/19]). Overall, the risk of malignancy for Afirma GSC suspicious nodules was 59% (16/27).

CONCLUSIONS

Afirma XA improved risk stratification of thyroid disease with a high risk of malignancy in Afirma GSC suspicious nodules. A negative Afirma XA result, however, should not be used as a rule-out test.

Interobserver agreement and risk of malignancy using the International Academy of Cytology Yokohama System for reporting breast FNA biopsy in a liquid-based exclusive cohort

BACKGROUND

Per the College of American Pathologist's National Breast Fine Needle Aspiration Biopsy (FNAB) Practice Survey, ∼40% of laboratories use liquid-based cytology (LBC) for breast FNAB. The reproducibility of the International Academy of Cytology Yokohama System (YS) for reporting breast FNAB on LBC was explored.

DESIGN

Breast FNAB specimens submitted as LBC only (all ThinPrep) between January 2017 and January 2021 were retrieved. Cases without histopathologic follow-up were excluded. Clinical and radiologic information was collected. One cytologist and six cytopathologists rendered diagnoses per YS. All reviewers were blinded to the original diagnosis and histopathologic follow-up. The risk of malignancy was calculated. Concordance rates were calculated by a weighted Cohen Kappa score (κ).

RESULTS

Review of 110 cases demonstrated substantial to near-perfect agreement between each reviewer (κ = 0.73-0.91) and follow-up histopathology (κ = 0.66-0.85). The agreement was lowest in the inadequate (κ = 0.05) and atypical (κ = 0.04) categories. The lack of concordance in the atypical category was common in cases with low cellularity or incomplete structural features. The risk of malignancy for inadequate, benign, atypical, suspicious for malignancy, and malignant categories were 12.5% (2/16), 3% (2/65), 67%, (8/12) 100% (1/1), and 100% (16/16).

CONCLUSION

Interobserver agreement is excellent using the five YS categories in LBC. Lack of cellularity and incomplete architectural features were barriers to perfect agreement. Established pitfalls in the interpretation of LBC were cause for atypical diagnoses. Continuous training and education are recommended to avoid misdiagnosis because of the nonconventional cytomorphologic features of LBC and to improve inadequate and atypical rates within YS.

Diagnostic interobserver agreement for thyroid fine-needle aspirates: Effects of reviewer experience and molecular diagnostics

OBJECTIVES

Few cytologically indeterminate thyroid fine-needle aspirations (FNAs) harbor BRAF V600E. Here, we assess interobserver agreement for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III (atypia of undetermined significance [AUS]) FNAs harboring BRAF V600E and contrast their features with those harboring non-BRAF V600E alterations, with attention to cytopathology experience.

METHODS

Seven reviewers evaluated 5 AUS thyroid FNAs harboring BRAF V600E. To blind reviewers, cases were intermixed with 19 FNAs falling within other TBSRTC categories and in which genetic alterations other than BRAF V600E had been identified (24 FNAs total). Interobserver agreement against both "index" and most popular ("mode") diagnoses was calculated. Four additional BRAF V600E cases were independently reviewed.

RESULTS

Reviewers included 3 trainees and 3 American Board of Pathology (board)-certified cytopathologists. Board-certified cytopathologists, whose experience ranged from 2 to more than 15 subspecialty practice years, had known AUS rates. BRAF V600E was identified in 5 of 260 (2%) AUS FNAs. Interobserver agreement was higher among cytopathologists with more experience. Mode diagnosis differed from index diagnosis in 6 of 11 cases harboring RAS-like alterations; mode diagnosis was AUS in 4 of 5 BRAF V600E FNAs.

CONCLUSIONS

Atypia of undetermined significance of thyroid FNAs harboring BRAF V600E is uncommon yet relatively reproducible, particularly among pathologists with experience. It is advisable to sequence BRAF across V600 in such cases.

Challenges and pitfalls in pancreatobiliary cytopathology

BACKGROUND

The advances of minimally invasive endoscopy-guided procedures that usually yield limited diagnostic material changed pancreaticobiliary cytopathology into one of the most challenging areas of Cytopathology given the abundance of differential diagnoses to be considered when dealing with limited specimens.

SUMMARY

We describes a few challenging, examples of potential pitfalls in pancreatobiliary cytopathology evaluation collected from a busy academic hospital (tertiary) center. Case 1 illustrates the challenges in handling paucicellular specimens from pancreatic solid lesions in which, differential diagnoses may include acinar cell carcinoma, neuroendocrine tumors, adenocarcinoma, or even benign pancreatic tissue, among others. Case 2 illustrates the pitfalls in evaluating limited specimens from patients with chronic pancreatitis specially when distinguishing exuberant reactive atypia from dysplastic changes is mandatory. Case 3 illustrates pitfalls in distinguishing malignancy from reactive changes in biliary brushing specimens from patients with Primary Sclerosing Cholangitis. Finally, cases 4 and 5 highlight the importance of including the possibility of pancreatic metastasis in the differential diagnoses of some pancreatic lesions.

KEY MESSAGES

Over time, there has been an increasing demand for pathologists to render diagnoses on limited specimens obtained through minimally invasive procedures which can be frequently challenging even for the most experienced professionals. In many difficult cases, salvaging additional material for a cell block can turn out to be extremely helpful given the possibility of utilizing additional ancillary tests for diagnostic confirmation.

The current state of digital cytology and artificial intelligence (AI): global survey results from the American Society of Cytopathology Digital Cytology Task Force

INTRODUCTION

The integration of whole slide imaging (WSI) and artificial intelligence (AI) with digital cytology has been growing gradually. Therefore, there is a need to evaluate the current state of digital cytology. This study aimed to determine the current landscape of digital cytology via a survey conducted as part of the American Society of Cytopathology (ASC) Digital Cytology White Paper Task Force.

MATERIALS AND METHODS

A survey with 43 questions pertaining to the current practices and experiences of WSI and AI in both surgical pathology and cytology was created. The survey was sent to members of the ASC, the International Academy of Cytology (IAC), and the Papanicolaou Society of Cytopathology (PSC). Responses were recorded and analyzed.

RESULTS

In total, 327 individuals participated in the survey, spanning a diverse array of practice settings, roles, and experiences around the globe. The majority of responses indicated there was routine scanning of surgical pathology slides (n = 134; 61%) with fewer respondents scanning cytology slides (n = 150; 46%). The primary challenge for surgical WSI is the need for faster scanning and cost minimization, whereas image quality is the top issue for cytology WSI. AI tools are not widely utilized, with only 16% of participants using AI for surgical pathology samples and 13% for cytology practice.

CONCLUSIONS

Utilization of digital pathology is limited in cytology laboratories as compared to surgical pathology. However, as more laboratories are willing to implement digital cytology in the near future, the establishment of practical clinical guidelines is needed.

Digital cytology part 2: artificial intelligence in cytology: a concept paper with review and recommendations from the American Society of Cytopathology Digital Cytology Task Force

Digital cytology and artificial intelligence (AI) are gaining greater adoption in the cytology laboratory. However, peer-reviewed real-world data and literature are lacking in regard to the current clinical landscape. The American Society of Cytopathology in conjunction with the International Academy of Cytology and the Digital Pathology Association established a special task force comprising 20 members with expertise and/or interest in digital cytology. The aim of the group was to investigate the feasibility of incorporating digital cytology, specifically cytology whole slide scanning and AI applications, into the workflow of the laboratory. In turn, the impact on cytopathologists, cytologists (cytotechnologists), and cytology departments were also assessed. The task force reviewed existing literature on digital cytology, conducted a worldwide survey, and held a virtual roundtable discussion on digital cytology and AI with multiple industry corporate representatives. This white paper, presented in 2 parts, summarizes the current state of digital cytology and AI practice in global cytology practice. Part 1 of the white paper is presented as a separate paper which details a review and best practice recommendations for incorporating digital cytology into practice. Part 2 of the white paper presented here provides a comprehensive review of AI in cytology practice along with best practice recommendations and legal considerations. Additionally, the cytology global survey results highlighting current AI practices by various laboratories, as well as current attitudes, are reported.

Digital cytology part 1: digital cytology implementation for practice: a concept paper with review and recommendations from the American Society of Cytopathology Digital Cytology Task Force

Digital cytology and artificial intelligence (AI) are gaining greater adoption in the cytopathology laboratory. However, peer-reviewed real-world data and literature are lacking regarding the current clinical landscape. The American Society of Cytopathology in conjunction with the International Academy of Cytology and the Digital Pathology Association established a special task force comprising 20 members with expertise and/or interest in digital cytology. The aim of the group was to investigate the feasibility of incorporating digital cytology, specifically cytology whole slide scanning and AI applications, into the workflow of the laboratory. In turn, the impact on cytopathologists, cytologists (cytotechnologists), and cytology departments were also assessed. The task force reviewed existing literature on digital cytology, conducted a worldwide survey, and held a virtual roundtable discussion on digital cytology and AI with multiple industry corporate representatives. This white paper, presented in 2 parts, summarizes the current state of digital cytology and AI practice in global cytology practice. Part 1 of the white paper presented herein is a review and offers best practice recommendations for incorporating digital cytology into practice. Part 2 of the white paper provides a comprehensive review of AI in cytology practice along with best practice recommendations and legal considerations. Additionally, the results of a global survey regarding digital cytology are highlighted.

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).

Are we on track for diagnosing high-grade urothelial carcinoma with a minimum quantity of five malignant cells in lower tract specimens? Critical analysis of The Paris System Quantitation Criteria

BACKGROUND

The Paris System for Reporting Urinary Cytology (TPS) has gained universal acceptance as the standard for reporting urine cytology requiring at least 5-10 malignant cells to diagnose high-grade urothelial carcinoma (HGUC) in lower and upper urinary tract specimens, respectively. These quantitation criteria are still subject to discussion, and this study specifically aims to validate the quantitation criterion of HGUC in lower urinary tract.

DESIGN

The authors reviewed two cohorts of lower urinary tract cases. The first cohort consisted of 100 liquid-based ThinPrep slides with the diagnosis of HGUC having positive histology on concurrent or follow-up biopsies within 3 months. The second cohort was 36 HGUC cases with negative histology on concurrent biopsies and within 3 months. The number of high-grade cells (HGCs) meeting the TPS qualitative criteria were counted under the light microscope driven in a grid-like manner.

RESULTS

The first 100 urine samples showed five cases (5.0%) with three HGCs, three cases (3.0%) had four HGCs, five cases (5.0%) showed five HGCs, and 25 cases (25.0%) had between 6-10 HGCs. The risk of high-grade malignancy (ROHM) in cases with five or more HGCs was 100%, whereas those with three HGCs was 60.0%. The second cohort of HGUC was considered "positive" despite a negative histology.

CONCLUSION

This study confirms that quantitation is an essential key to diagnose HGUC. The current TPS criterion of a minimum of five malignant cells in lower tract is robust with a ROHM of 100%. Diagnosing HGUC with less than five HGCs runs the risk of lowering the ROHM.

Optimal fluid volume for detecting malignancy in serous effusions: a single institution experience

INTRODUCTION

Detection of malignant cells in serous fluids is an indicator of advanced stage of malignancy and is critical in clinical management decisions and prompt treatment initiation. The minimum volume which is ideal for detecting malignancy in serous fluid is not well established. In this study, we aim to identify optimal volume that will be ideal for adequate cytopathological diagnosis.

MATERIALS AND METHODS

A total of 1597 samples of serous fluids from 1134 patients were included in the study. Samples were diagnosed based on International System for Reporting Serous Fluid Cytopathology (ISRSFC). Clinicopathologic results from different diagnostic groups were compared and statistically analyzed.

RESULTS

Pleural fluids comprised 890 (55.7%) specimens, followed by 456 (28.6%) peritoneal, 128 (8%) ascites, and 123 (7.7%) pericardial fluid specimens. The majority were negative for malignancy (1138, 71.3%), followed by malignant (376, 23.5%), atypical (59, 3.7%), and suspicious for malignancy (24, 1.5%). Malignancy was identified in sample with volumes from 5 mL to 5000 mL. Rate of detection of malignant cells increased significantly with higher sample volumes. For malignancy detection the optimal volume for overall serous fluid is 70 mL. Pericardial fluid is an exception, with lower mean volume and significantly lower proportion of cases with malignant diagnosis.

CONCLUSIONS

Our study indicates that higher fluid volumes have a higher rate of malignancy detection and a low false-negative rate. We recommend a minimum of 70 mL of serous fluid for optimal cytopathologic examination and malignancy detection. Pericardial fluid is an exception, with lower mean volume and thus lower requirement.

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.

Abstract 5414: Automated detection of high-grade urothelial carcinoma from urine cytology slides using attention-based deep learning

Urine cytology has long been an effective and non-invasive test for the detection of bladder urothelial carcinomas (UC) routinely performed in cases of unexplained hematuria or for monitoring patients with UC. In cytopathology practice, urine cytology specimens are examined manually with a light microscope to identify morphologic features associated with different diagnostic categories based on the Paris System (TPS) for Reporting Urinary Cytology. Specifically, the diagnosis of high-grade urothelial carcinoma (HGUC) requires the identification of > 5-10 cells with a nuclear/cytoplasm ratio of 0.7 or greater and hyperchromasia together with coarse chromatin or irregular nuclear membranes. However, the task of identifying HGUC involves a substantial degree of manual review and is often associated with intra-and inter-observer variability. To address this, we have designed an accurate and efficient deep learning system capable of automatically distinguishing between HGUC and non-HGUC using digitized cytology slides. Our model has been developed using a retrospective cohort of 158 digitized urine ThinPrep cytology slides consisting of HGUC (n=98) and negative for HGUC (n=60). The model was then prospectively validated on a cohort of 105 urine cytology slides that were also independently reviewed prospectively in a blinded manner by a cytopathologist and cytotechnologist. Our system uses Otsu’s method for automatic image thresholding followed by dividing images into non-overlapping tiles of 500 × 500 pixels at the highest magnification. Subsequently, we use a pre-trained ResNet50 model to extract features which are used for training our attention-based multiple instance learning framework. For the training task, our retrospective cohort (158 slides) has been divided into 10 different splits each consisting of training (70%), validation (15%), and testing (15%) sets. The training and validation sets were used for the model training and optimalization, respectively, while the testing set was used for assessing the performance. This process yielded 10 different models with an average Area Under the ROC Curve (AUC) of 0.80 in the testing set. The best performing model had an AUC of 0.90 and an accuracy of 0.88. This model was subsequently validated prospectively in an independent testing cohort with 105 slides. In the prospective testing cohort, the model was able to accurately distinguish between HGUC and non-HGUC with an AUC of 0.83, accuracy of 0.76, sensitivity of 0.89, and specificity of 0.62. Additionally, our system can detect slide regions with high attention score for HGUC which are enriched in atypical urothelial cells. These findings show that our system can be utilized to assist cytopathologists in assessing urine cytology slides and to detect regions with high-diagnostic relevance for further assessment which is expected to reduce the time needed for manual review.

Citation Format: Mohamed Omar, David Kim, Luigi Marchionni, Momin T. Siddiqui. Automated detection of high-grade urothelial carcinoma from urine cytology slides using attention-based deep learning. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5414.

Primary Effusion Lymphoma in an HIV-Negative Patient with Chronic Myeloid Leukemia Treated with Dasatinib

INTRODUCTION

Primary effusion lymphoma (PEL) is a malignant lymphomatous effusion, which by definition is Kaposi sarcoma herpesvirus/human herpesvirus 8-positive. PEL typically occurs in HIV-infected patients but can also occur in HIV-negative individuals, including in organ transplant recipients. Tyrosine kinase inhibitors (TKIs) are currently the standard of care for patients with chronic myeloid leukemia (CML), BCR::ABL1-positive. Although TKIs are extremely effective in treating CML, they alter T-cell function by inhibiting peripheral T-cell migration and altering T-cell trafficking and have been associated with the development of pleural effusions.

CASE PRESENTATION

We report a case of PEL in a young, relatively immunocompetent patient with no history of organ transplant receiving dasatinib for CML, BCR::ABL1-positive.

DISCUSSION

We hypothesize that the loss of T-cell function secondary to TKI therapy (dasatinib) may have resulted in the unchecked cellular proliferation of Kaposi sarcoma herpesvirus (KSHV)-infected cells, leading to the emergence of a PEL. We recommend cytologic investigation and KSHV testing in patients being treated with dasatinib for CML who present with persistent or recurrent effusions.

Chondroblastoma: Cytomorphologic Analysis of Ten Cases with Review of the Literature

INTRODUCTION

Chondroblastoma (CB) is a rare, benign cartilage-producing tumor, typically affecting the epiphysis of long bones in skeletally immature individuals. There have been only limited case reports describing the cytomorphologic features of this tumor, and thus the cytopathologic diagnostic criteria are controversial. Herein, we report the cytologic findings of 10 CB cases, discuss the diagnostic criteria and critical differential diagnosis, along with a comprehensive review of the literature.

METHODS

We performed a retrospective search of our cytopathology and surgical pathology databases for cases diagnosed as CB that had corresponding cytology specimens from four large medical institutions. All available cytopathology specimens were retrieved and reviewed. Clinicopathologic and radiologic data were recorded.

RESULTS

Ten cases were retrieved from eight patients aged 15 to 42 years (mean, 24 years), five of whom were males. Eight cases represented primary tumors while two cases were recurrences. Three cases occurred in the femur, two cases occurred in the humerus, while one case occurred in each of the glenoid, talus, and proximal phalanx of the 3rd toe. The cytologic diagnosis of CB was achieved in seven cases. The neoplastic mononuclear cells were present in all cases and their cytologic features were similar. These cells displayed round to oval eccentric nuclei, evenly distributed chromatin, and inconspicuous nucleoli; few of which had nuclear indentations. Multinucleated giant cells were present in nine cases (90%). Fragments of chondromyxoid matrix were present in four cases on cytologic preparations (40%). Cell blocks were available in eight cases. Mononuclear and multinucleated giant cells were present in all adequate cell blocks and their cytologic features were identical to those seen in the smears. The chondroid matrix was present in only three of the adequate cell blocks (43%).

CONCLUSION

We concluded that with the appropriate clinical and radiologic setting, the diagnosis of CB can be achieved on cytology if characteristic chondroblasts are present. The presence of chondromyxoid matrix is a helpful clue but is not necessary for the diagnosis. As in surgical pathology, cytologic evaluation of bone tumors should be interpreted in conjunction with clinical and radiologic findings.

Cytopathology of rare gastric mesenchymal neoplasms: A series of 25 cases and review of literature

BACKGROUND

Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm arising in the stomach. However, a number of other rare mesenchymal neoplasms do occur at this anatomic site, which often presents a diagnostic challenge for cytopathologists on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Our study aims to selectively present the clinico-radiological and cytopathological characteristics of these rare "non-GIST" neoplasms, as well as their differential diagnoses.

MATERIAL AND METHODS

We performed a 20 year retrospective search in the cytopathology database of our two large medical institutions for non-GIST mesenchymal neoplasms arising in the stomach and diagnosed on EUS-FNA. Data regarding the patients' demographics and radiological findings were analysed. All available cytopathology specimens were reviewed. The cytomorphological characteristics and the accompanying immunohistochemical stains, when available, were subsequently analysed.

RESULTS

Twenty-five cases of gastric mesenchymal tumours were selectively included in the study after excluding all cases of GIST (n = 113) diagnosed on FNA. These cases included 10 leiomyomas (40%), eight schwannomas (32%), five glomus tumours (20%), one perivascular epithelioid cell neoplasm, and one desmoid tumour. The specimen cellularity was variable and ranged from hypocellular to highly cellular. Most smears were composed of spindle cells with a few showing epithelioid morphology. Cell blocks were available in 20 cases and a range of immunohistochemical ancillary studies were performed. DOG-1, c-KIT, smooth muscle actin (SMA), and S100-protein were the most common immunomarkers done.

CONCLUSION

Our study highlights important cytomorphological characteristics of rare mesenchymal neoplasms arising in the stomach. In the appropriate clinical setting and with the help of immunohistochemistry, an accurate diagnosis of these neoplasms can be achieved.

The World Health Organization Reporting System for Pancreaticobiliary Cytopathology

The World Health Organization (WHO), the International Academy of Cytology, and the International Agency for Research on Cancer, with expert contributors from around the world, present an international approach to standardized reporting of pancreaticobiliary cytopathology. This reporting system is one of the first in a series from various body sites that mirror the WHO Classification of Tumours series and provides an evidence-based terminology system with associated risk of malignancy and diagnostic management recommendation per diagnostic category. 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 six-tiered system with a seven-tiered system: "insufficient/inadequate/nondiagnostic"; "benign (negative for malignancy)," "atypical," "pancreaticobiliary neoplasm of low risk/low grade," "pancreatic neoplasm of high risk/high grade," "suspicious for malignancy," and "malignant." The principal differences between the WHO and the PSC systems revolve around the classification of neoplasia. In the PSC system, there was a single category for "neoplastic" lesions that includes two groups, one for "benign neoplasms" [primarily serous cystadenoma] and one named "other," dominated by premalignant intraductal neoplasms (primarily intraductal papillary mucinous neoplasms) and low-grade malignant neoplasms [pancreatic neuroendocrine tumors (PanNETs) and solid pseudopapillary neoplasms (SPNs)]. 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 WHO Classification of Digestive System Tumours, thus leaving in the "neoplasm" category primarily those noninvasive premalignant lesions of the ductal system. These neoplasms are divided by the cytomorphological grade of the epithelium into low risk/low-grade and high risk/high-grade, with distinctly different risks of malignancy. As with the PSC system, the WHO system advocates close correlation with imaging and encourages incorporation of ancillary testing into the final diagnosis, such as biochemical (CEA and amylase) and molecular testing of cyst fluid and bile duct brushings. Key diagnostic cytopathological features of specific lesions or neoplasms, ancillary studies for diagnostic and prognostic evaluation, and implications of diagnosis for patient care and management are discussed. In addition, the WHO system includes reporting and diagnostic management options that recognize the variations in the availability of diagnostic and prognostic ancillary testing modalities in low- and middle-income countries, where cytopathology is particularly useful and is increasingly available in the absence of histopathological services.

Evaluating the role of Z-stack to improve the morphologic evaluation of urine cytology whole slide images for high-grade urothelial carcinoma: Results and review of a pilot study

BACKGROUND

Whole slide imaging (WSI) adoption has been slower in cytopathology due, in part, to challenges in multifocal plane scanning on 3-dimensional cell clusters. ThinPrep and other liquid-based preparations may alleviate the issue by reducing clusters in a concentrated area. This study investigates the use of Z-stacked images for diagnostic assessment and the experience of evaluating urine ThinPrep WSI.

METHODS

Thirty ThinPrep urine cases of high-grade urothelial carcinoma (n = 22) and cases of negative for high-grade urothelial carcinoma (n = 8) were included. Slides were scanned at 40× magnification without Z-stack and with Z-stack at 3 layers, 1 μm each. Six cytopathologists and 1 cytotechnologist evaluated the cases in 2 rounds with a 2-week wash-out period in a blinded manner. A Cohen's Kappa (CK) calculated concordance rates. A survey after each round evaluated participant experience.

RESULTS

CK with the original report ranged from 0.606 to 1.0 (P < .05) without Z-stack and 0.533 to 1.0 (P < .05) with Z-stack both indicating substantial-to-perfect concordance. For both rounds, interobserver CK was moderate-to-perfect (0.417-1.0, P < .05). Intraobserver CK was 0.697-1.0 (P < 0.05), indicating substantial to perfect concordance. The average scan time and file size for slides without Z-stack and with Z-stack are 6.27 minute/0.827 GB and 14.06 minute/2.650 GB, respectively. Surveys demonstrated a range in comfort and use with slightly more favorable opinions for Z-stacked cases.

CONCLUSIONS

Z-stack images provide minimal diagnostic benefit for urine ThinPrep WSI. In addition, Z-stacked urine WSI does not justify the prolonged scan times and larger storage needs compared to those without Z-stack.

NR4A3 Immunostain Is a Highly Sensitive and Specific Marker for Acinic Cell Carcinoma in Cytologic and Surgical Specimens

OBJECTIVES

Salivary gland acinic cell carcinoma (AciCC) has recognizable cytomorphologic features that can overlap with benign and malignant entities, creating a diagnostic challenge. AciCC harbors a t(4;9) translocation increasing nuclear receptor subfamily 4 group A member 3 (NR4A3) expression, detectable by immunohistochemistry (IHC) on surgical resection (SR). NR4A3 IHC cytology data are limited. Here, we examine NR4A3 IHC on smears, cell blocks (CBs), and SRs of AciCC and its mimickers.

METHODS

Our cohort comprised AciCC (including high-grade transformation), secretory carcinoma, mucoepidermoid carcinoma (MEC), Warthin tumor, pleomorphic adenoma (PA), cellular PA, carcinoma ex-PA, oncocytic carcinoma, oncocytoma, and nodular oncocytosis. NR4A3 IHC (Santa Cruz Biotechnology and Origene antibodies) was positive if more than 5% tumor cells showed nuclear staining.

RESULTS

Among CBs, 90% of AciCC cases and none of the mimickers expressed NR4A3. Among SRs, 100% of AciCC cases showed diffuse NR4A3, whereas one high-grade MEC expressed focal NR4A3. Concordance was 95% with two antibody clones. Sensitivity, specificity, positive predictive value, and negative predictive value were 90%, 100%, 100%, and 94.7% for CBs and 100%, 98.8%, 92.3%, and 100% for SRs, respectively. NR4A3 immunostaining was demonstrable on smears from an AciCC case.

CONCLUSIONS

NR4A3 IHC can be a robust diagnostic tool to identify AciCC, especially for cytology specimens.

Fine-needle aspiration cytopathology of soft tissue myoepithelioma: an analysis of seven cases

INTRODUCTION

Soft tissue myoepithelioma (STM), a rare mesenchymal neoplasm morphologically analogous to its more common salivary gland (SG) counterpart, is the subject of single case reports regarding its fine-needle aspiration (FNA) biopsy. To our knowledge, ours is the first case series of STM.

MATERIALS AND METHODS

A search was made of our pathology databases for cases diagnosed as STM. FNA biopsy smears and cell blocks were performed using standard techniques.

RESULTS

Seven cases were retrieved from 4 men and 3 women (M:F = 1.3:1; age range: 25-79 years, x = 54 years). All but 1 presented as a primary neoplasm. Six aspirates were from the extremities, and 1 from the abdominal wall. Mean tumor size was 5.7 cm. Cytologic diagnosis of STM or suspicious for STM was made in 3 cases (43%). Remaining FNA diagnoses were spindle cell neoplasm/lesion (2), spindle cell sarcoma (1), and extraskeletal myxoid chondrosarcoma (1). Three cases were composed primarily or solely of uniform spindle cells, 3 primarily of uniform epithelioid cells with plasmacytoid features, and 1 case a mixture of these 2 cell types. Myxoid/chondromyxoid stroma was relatively abundant except in the single hypocellular example. Immunohistochemical (IHC) testing performed in 71% was nonspecific, but positive with S-100 in 4 of 5, EMA in 3 of 3, calponin in 2 of 2, and keratin in 1 of 3 examples.

CONCLUSION

FNA biopsy smears of STM are remarkably similar cytomorphologically to their SG equivalent. However, STM can be misidentified principally as extraskeletal myxoid chondrosarcoma, thus requiring a relatively broad IHC panel for a specific diagnosis.

Underrecognized Patterns of High-Grade Squamous Intraepithelial Lesion on ThinPrep Preparations

OBJECTIVES

To identify less readily identifiable patterns of high-grade squamous intraepithelial lesions (HSIL) in negative human papillomavirus (HPV)-positive Papanicolaou (Pap) tests on ThinPrep preparations.

METHODS

Of all HPV-positive Pap tests that were negative for intraepithelial lesion or malignancy (NILM) from July 2013 to June 2018, those with HSIL on subsequent histology within 6 months were identified. ThinPrep slides from the latter group (group 1) and from NILM HPV-negative Pap tests with negative follow-up (group 2) were reviewed independently by 4 participants. Group 1 cases were then reviewed together for consensus and with the ThinPrep Imaging System (TIS). Any discrepancies from the original interpretation were recorded.

RESULTS

The study cohort included 57 cases each in groups 1 and 2. On final review of group 1 cases, 17 (29.8%) were classified as NILM or unsatisfactory. Of the remaining, 4 cases revealed rare abnormal cells not flagged by the TIS in the fields of view. In the 36 cases (63.1%) with screening or interpretative errors, the key cytologic findings accounting for major discrepancies included atypical metaplastic cells, atypical repair, rare syncytial groups, and atypical immature metaplastic cells.

CONCLUSIONS

There are 3 main underrecognized patterns of HSIL in cervical cytology: atypical metaplastic cells, atypical repair, and rare syncytial groups.

Next-Generation Sequencing of Cell-Free DNA Extracted From Pleural Effusion Supernatant: Applications and Challenges

Cell-free DNA (cfDNA) extracted from diverse specimen types has emerged as a high quality substrate for molecular tumor profiling. Analytical and pre-analytical challenges in the utilization of cfDNA extracted from pleural effusion supernatant (PES) are herein characterized in patients with metastatic non-small cell lung carcinoma (NSCLC). Pleural effusion specimens containing metastatic NSCLC were collected prospectively. After ThinPrep® (TP) and cell block (CB) preparation, DNA was extracted from residual PES and analyzed by gel electrophoresis for quality and quantity. Libraries were prepared and sequenced with a targeted next-generation sequencing (NGS) platform and panel clinically validated for plasma specimens. Results were compared with DNA extracted from corresponding FFPE samples that were sequenced using institutional targeted NGS assays clinically validated for solid tumor FFPE samples. Tumor (TC) and overall cellularity (OC) were evaluated. Fourteen specimens were collected from 13 patients. Median specimen volume was 180 mL (range, 35–1,400 mL). Median TC and OC on TP slides and CB sections were comparable. Median extracted DNA concentration was 7.4 ng/μL (range, 0.1–58.0 ng/μL), with >5 ng/μL DNA extracted from 10/14 specimens (71%). Mutations were identified in 10/14 specimens, including 1/3 specimens with median molecular coverage <1,000 reads. The minimal detected allelic fraction was 0.6%. NGS was falsely negative for the presence of one driver mutation. No correlation was identified between sample volume or OC, quality or quantity of extracted DNA, or mutation detection. Despite analytical and pre-analytical challenges, PES represents a robust source of DNA for NGS.

Nuclear hypochromasia: Shedding light on the "lightness" of high-grade urothelial carcinoma

BACKGROUND

The Paris system (TPS) has provided a standardized classification for reporting urinary cytology, specifically high-grade urothelial carcinoma (HGUC). While hyperchromasia is well described in HGUC, there exists little data on nuclear hypochromasia in HGUC. Our focus was to investigate the incidence of hypochromasia in HGUC and if it should become a criterion for HGUC.

DESIGN

All cases of HGUC at our institution for a 3-year interval (2017-2019) using TPS were reviewed. Each case had a single ThinPrep slide and concurrent biopsy or resection specimen to confirm the diagnosis within 30 days. The presence of hypochromasia was evaluated, and cases with hypochromasia were stratified based on the tumor cell percentage. Cases with hypochromasia in 5% or greater of the tumor cells were considered "positively identified" for hypochromasia.

RESULTS

We reviewed 117 cases of HGUC and identified nuclear hypochromasia in 12 cases (10.2%) within 5% or greater of the tumor cells. These 12 cases were further assessed based on if tumor cells showed hypochromasia in 5%-49% of the sample, or greater than 50% of the sample. Hypochromasia in 5%-49% of tumor cells was present in 8/117 cases (6.8%); whereas in 50% or greater samples 4/117 cases (3.4%) showed hypochromasia. No cases were identified where hypochromasia was noted in less than 5% of the tumor cells.

CONCLUSION

TPS and use of hyperchromasia as a feature of HGUC is affirmed. However, hypochromasia, while not diagnostic in isolation, is present in a sub-set of patients with HGUC (10.2%) and should be considered as a variance noted in the nuclei of HGUC.

Incorporating cytologic adequacy assessment into precision oncology workflow using telepathology: An institutional experience

BACKGROUND

Tumor sample quality and quantity determine the success of somatic mutation analysis. Thus, a rapid on-site evaluation (ROSE) tumor cytology adequacy assessment was incorporated into the workflow of precision oncology at Weill Cornell Medicine in New York City. Optimal samples were obtained from 68 patients with metastatic cancer.

METHODS

Cytopathologists performed ROSE on fine-needle aspirate samples via telepathology, and subsequently core-needle biopsies were obtained. In a retrospective manner, the concordance between adequacy assessment and the success rate of the procedure was evaluated to obtain sufficient tumor tissue for next-generation sequencing (NGS).

RESULTS

Out of the 68 procedures, 43 were documented as adequate and 25 were documented as inadequate. The diagnostic yield of adequate procedures was 100%. Adequacy evaluation predicted the success rate of molecular profiling in 40 of 43 procedures (93%; 95% CI, 80.9-98.5 procedures). The success rate of molecular testing was significantly higher in the adequate group: 93% compared with 32% in the inadequate group (P < .0005). Seven procedures that failed to provide quality material for mutational analysis and pathological diagnosis were evaluated as inadequate. Cell block provided sufficient DNA for NGS in 6 cases. In 2 cases, a core biopsy could not be performed; hence, the fine-needle aspirate material confirmed the diagnosis and was used for NGS testing.

CONCLUSION

These results support the incorporation of ROSE into the workflow of precision oncology to obtain high-quality tissue samples from metastatic lesions. In addition, NGS testing of concurrent cytology specimens with adequate cellularity can be a surrogate for NGS testing of biopsy specimens.

Cytopathology of chondromyxoid fibroma: a case series and review of the literature

INTRODUCTION

Chondromyxoid fibroma is a rare bone tumor characterized by immature myxoid mesenchymal tissue showing early primitive cartilaginous differentiation. There have been limited case reports describing the cytologic features of chondromyxoid fibroma. Herein, we reported cytologic features of chondromyxoid fibroma on fine-needle aspiration (FNA).

MATERIALS AND METHODS

We performed a retrospective search in our cytopathology and surgical pathology database for cases diagnosed as chondromyxoid fibroma that had corresponding cytology specimens from three medical institutions. All available cytopathology specimens were reviewed.

RESULTS

Eight cases were retrieved from patients aged 16-77 years (mean, 51 years), and M:F ratio of 1.7:1. Seven tumors (88%) were primary, and most (62%) occurred in flat bones. Cytologic diagnoses were made in 6 cases with cytologic slides not available to review in 1 case. All cases showed metachromatic matrix in the background, while hyaline cartilage fragments were absent. All cases had two cell populations comprising oval to round cells and stellate to spindle cells. The spindle to stellate cells were more commonly embedded in matrix material. Moderate atypia (hyperchromasia and moderate anisonucleosis) was present in 4 cases (80%), while no mitotic figure was present in all cases.

CONCLUSIONS

Our study highlights common cytologic features of chondromyxoid fibroma, including the presence of the spindle or stellate cells embedded in matrix material. Hyaline cartilage is uncommon and, if present, diagnostic considerations should include enchondroma or low-grade chondrosarcoma. A specific cytologic diagnosis primarily using FNA samples can be challenging but possible when evaluated in conjunction with clinical and radiologic data.

Renal medullary carcinoma involving serous cavity fluids: a cytomorphologic study of 12 cases

INTRODUCTION

Renal medullary carcinoma (RMC) is a highly lethal adenocarcinoma with a propensity for widespread metastatic disease in young patients. It is strongly associated with sickle cell trait and shows the loss of SMARCB1 (also known as INI1 or BAF47) protein expression. In the present study, we reviewed a series of 12 patients for whom the cytology specimens played a significant role in patient treatment.

MATERIALS AND METHODS

We performed a retrospective case review of patients with a history of RMC from 3 large tertiary care pathology practices.

RESULTS

A total of 12 patients were identified with histologically confirmed RMC who had had pleural, pericardial, or urine specimens involved by their disease or had undergone initial kidney fine needle aspiration. Patient age ranged from 13 to 37 years (median, 21.5 years). All 12 patients were black or of African descent, and 10 had a confirmed history of sickle cell trait. Of the 12 patients, 11 (92%) had fluid specimens involved by metastatic tumor at some point in their clinical course, and 4 (33%) had initially presented with pericardial and/or pleural effusions or urine specimens that were positive for malignancy. Cytologic examination predominantly showed fragments of 3-dimensional "tumor balls" with smooth borders, fine pale cytoplasm with vacuolization, and highly pleomorphic nuclei with irregular nuclear membranes and coarse to vesicular chromatin and single prominent nucleoli.

CONCLUSIONS

The cytomorphology of RMC involving serous fluids is nonspecific and in keeping with metastatic high-grade adenocarcinoma. In a young patient presenting with no history of malignancy and a pleural or pericardial effusion, triaging the material for ancillary studies and a nuanced assessment of patient history and radiologic findings will be critical.

A Subset of Intrahepatic Cholangiocarcinomas Express Albumin RNA as Detected by In Situ Hybridization

Intrahepatic cholangiocarcinomas (ICCs) show morphologic diversity, ranging from tumors composed of nonmucinous small ducts to mucin-producing large duct tumors to tumors with mixed hepatocellular carcinoma features. Diagnosing ICCs can be difficult, especially on biopsy, not only because of the morphologic diversity, but also because metastatic tumors are often in the differential diagnosis. Recently, branched DNA-based albumin RNA in situ hybridization (ISH) has been shown to be a potential sensitive and specific marker for ICC with 99% sensitivity. Using a different RNA ISH technology, we evaluated the expression of albumin RNA ISH in ICC. We performed RNA ISH for albumin using RNAscope on 43 ICCs in a triplicate tissue microarray. Albumin RNA ISH was positive in 18 of 43 (42%) ICCs. Five of the 6 (83%) combined hepatocellular carcinoma-CC were positive in the CC component. None of the tumors with mucin production were positive (0/9). In our cohort, albumin RNA ISH showed a sensitivity of 42% in ICCs, supporting the morphologic diversity of ICCs. Albumin RNA ISH does not appear to be a highly sensitive marker for ICC and hence cannot be used as a stand-alone marker for ICC.

Standardizing a volume benchmark for cerebrospinal fluids for optimal diagnostic accuracy

INTRODUCTION

Cerebral spinal fluid (CSF) cytomorphologic analysis remains the gold standard in the evaluation of malignant leptomeningeal involvement. However, collection of optimal volumes for adequate cytomorphologic evaluation is not standardized. Our study investigated optimal CSF volumes that result in a significant diagnostic result.

METHODS

A total of 4114 samples were retrospectively identified from 2014 to 2018, and 2557 samples had concurrent flow cytometry (FC) study. Each specimen was grouped as unsatisfactory, negative, atypical, or positive. Positive samples were grouped as either solid tumors, leukemia, or lymphoma by the type of malignancy detected. Demographic data as well as CSF source was recorded. Specimens with FC were separated by detection on cytology and/or FC. A t-test and ANOVA test were used to compare the average volumes for each group.

RESULTS

Average volumes for negative, atypical, and positive samples are 7.48 mL (95% CI: 7.33, 7.63), 7.97 mL (95% CI: 7.37, 8.57), and 8.44 mL (95% CI: 7.46, 9.43), respectively. Average volumes for solid tumors, leukemia, and lymphoma positive samples are 12.0 mL (95% CI: 9.11, 14.89), 6.73 mL (95% CI: 5.94, 7.53), and 8.44 mL (95% CI: 6.78, 10.09). For cases with FC, the volumes are 10.11 mL (95% CI: 9.28, 10.96), 7.28 mL (95% CI: 6.87, 7.70), and 6.86 mL (95% CI: 6.25, 7.49) for positive cytology only, positive cytology/FC, and negative for both, respectively.

CONCLUSIONS

Our results suggest that higher volumes produce better results for analysis. We recommend an optimal volume of 8.44 mL for cytologic work-up of malignancies. However, optimal volumes may differ based upon malignancy type and utilization of flow cytometry.

Cytopathology of extra-renal perivascular epithelioid cell tumor (PEComa): a series of 7 cases and review of the literature

INTRODUCTION

Perivascular epithelioid cell tumor (PEComa) is a family of rare mesenchymal tumors consisting of histologically and immunohistochemically distinctive perivascular epithelioid cells. Relatively little is known about the cytopathology of extra-renal PEComas. Because of a considerable range of morphology and their rarity, accurate cytologic classification can be challenging. We evaluated cytologic characteristics and diagnostic pitfalls of extra-renal PEComas on fine-needle aspiration (FNA).

MATERIALS AND METHODS

We performed a retrospective search in our cytopathology and surgical pathology database for cases diagnosed as PEComa that had corresponding cytology specimens from 3 medical institutions. All available cytopathology specimens were reviewed. We evaluated cytologic characteristics and recorded histologic diagnoses and immunohistochemical stains.

RESULTS

Seven FNA specimens from 6 patients were identified, and cytologic diagnoses were made in all cases as follows: PEComa (4 cases), most consistent with PEComa (1 case), malignant neoplasm (1 case), and hepatocellular carcinoma (1 case). Most specimens were moderately to highly cellular. Cell distribution occurred as tissue fragments with background proliferating capillaries. Most smears were composed of epithelioid cells showing mild to moderate anisonucleosis, abundant eosinophilic cytoplasm, well-defined borders, intranuclear pseudoinclusions, and prominent nucleoli. A combination of myoid and melanocytic markers was expressed in 6 cases except 1 case, which was called hepatocellular carcinoma.

CONCLUSIONS

This was the largest FNA series for extra-renal PEComas to date. Our study highlights some common cytomorphologic characteristics of PEComa with which cytopathologists should be familiar. In the right clinical and radiologic context, and with the aid of immunohistochemistry, a definitive diagnosis can be achieved.

High-grade urothelial carcinoma in urine cytology: different spaces - different faces, highlighting morphologic variance

INTRODUCTION

The Paris System for Reporting Urinary Cytology (TPS) was first published in 2016 to standardize reporting and placed a specific emphasis on high-grade urothelial carcinoma (HGUC). The urinary tract is anatomically divided into the upper tract (UT) and the lower tract (LT). A major morphologic criterion in TPS for HGUC defines the nuclear-to-cytoplasmic (N/C) ratio as ≥ 0.7. In this study, we evaluated N/C ratios of HGUC arising from UT and LT urine specimens, to ascertain differences due to location.

MATERIALS AND METHODS

Digital annotations of whole slide scanned images were performed and enumerated.

RESULTS

The cohort consisted of 59 ThinPrep specimens from 52 patients. The majority of the tumors were located in LT (39 of 59, 66.1%). A total of 590 cells were analyzed (10 cells per case). In UT, the average N/C was 0.58 and LT the average was 0.54 (P < 0.001). The average nuclear area for UT was 126.3 and for LT was 158.2 μm² (P = 0.01). The average cytoplasmic area for UT was 219.1 μm² and for LT was 296.2 μm² (P < 0.001). The average cellular circumference for UT was 59.4 μm and for LT was 66.1 μm (P < 0.001).

CONCLUSIONS

We found that UT HGUCs have higher N/C ratios, smaller cell circumference, smaller nuclei, and less cytoplasm compared with LT. When UT was divided into renal pelvis and ureter, no statistical difference was identified.

Assessing the diagnostic accuracy for pleomorphic adenoma and Warthin tumor by employing the Milan System for Reporting Salivary Gland Cytopathology: An international, multi-institutional study

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has established distinct diagnostic categories for reporting cytopathological findings, and each is associated with a defined risk of malignancy (ROM). However, the ROM is applied at the overall category level and is not specific for particular morphological entities within a category. Here, the diagnostic performance of the MSRSGC for pleomorphic adenoma (PA) and Warthin tumor (WT) is reported.

METHODS

The pathology archives of 11 institutions from 4 countries were retrospectively searched to identify all salivary gland fine-needle aspiration (FNA) biopsies with a differential or definitive diagnosis of PA or WT and all resection specimens with a diagnosis of PA or WT; only paired cases were included. All FNA diagnoses were retrospectively classified according to the MSRSGC.

RESULTS

A total of 1250 cases met the inclusion criteria, and they included 898 PA cases and 352 WT cases. The ROM in the benign neoplasm category was 3.0% and 1.3% for cases with a differential or definitive diagnosis of PA and WT, respectively. The ROM in the salivary gland neoplasm with uncertain malignant potential (SUMP) category was 2.7% and 18.8% for PA and WT, respectively (P = .0277). The diagnostic accuracy for PA and WT was 95.1% and 96.1%, respectively.

CONCLUSIONS

The diagnostic accuracy for PA and WT on FNA is high. Furthermore, these findings highlight the difference in the ROMs associated with 2 specific differential diagnoses in the SUMP category: basaloid neoplasms and oncocytoid neoplasms.

Preanalytic variables in quality and quantity of nucleic acids extracted from FNA specimens of thyroid gland nodules collected in CytoLyt: Cellularity and storage time

BACKGROUND

Morphologic and genetic analysis of thyroid nodules may be performed from a single vial. Preanalytic variables that affect nucleic acid extracted from a single vial are evaluated.

METHODS

Thyroid fine-needle aspiration (FNA) specimens collected in CytoLyt were evaluated. A ThinPrep slide was prepared. Extracted nucleic acids were analyzed using Oncomine Comprehensive Panel, version 2, after Ion AmpliSeq library preparation. A pathologist and a cytotechnologist enumerated specimen cellularity.

RESULTS

Fifty-six samples were collected from 55 nodules in 53 patients. Bethesda category correlated with cellularity (P = .01), and storage time (median, 43 days; range, 7-77 days) was longer for specimens in categories II and III than for those in categories IV and VI (P = .01). The mean specimen DNA concentration was 4.5 ng/µL (range, 0-23.8 ng/µL), and 25 (45%) had concentrations >3.3 ng/µL. The mean specimen RNA concentration was 4.8 ng/µL (range, 0-42.4 ng/µL), and 31 (55%) had concentrations >1.4 ng/µL. Nucleic acid quantity increased with epithelial cellularity. Storage time weakly correlated with the quantity of extracted DNA, independent of cellularity, but not extracted RNA. Greater proportions of cell-free DNA and lesser proportions of long, intact RNA fragments were extracted from a subset of samples with longer storage time. Among 15 single nucleotide variants, the median mutant allelic fraction was 15.1%. One false-negative result was identified. Five specimens subsequently determined to harbor a genetic alteration failed quality metrics.

CONCLUSIONS

Cellularity and storage time affect the quantity and quality of nucleic acid extracted from thyroid FNA specimens collected in CytoLyt. Further investigation will serve to quantify the magnitude of such effects and to elucidate other contributing factors.

Cytomorphologic findings of low-grade fibromyxoid sarcoma

INTRODUCTION

Low-grade fibromyxoid sarcoma (LGFMS) is a rare fibroblastic tumor characterized by a prolonged clinical course and malignant biological behavior. Given its deceptively bland cytomorphology, a diagnosis can be quite challenging notably on fine-needle aspiration (FNA). In an attempt to shed light on some of the distinctive cytomorphologic characteristics, this study was conducted to review all cases of LGFMS in our database, correlating available clinical data, immunohistochemical findings, and molecular analysis.

MATERIALS AND METHODS

This series included 20 FNAs from 18 patients with a histologically confirmed LGFMS diagnosis from 3 large academic institutions. Detailed cytomorphologic analysis for each case was documented in conjunction with corresponding clinical characteristics and provided ancillary testing.

RESULTS

Out of 14 adequate FNA samples, 9 (64.2%) demonstrated a mixture of fibrous and myxoid pattern; the majority of cases were composed of deceptively bland tumor cells with rare nuclear pleomorphism and nuclear membrane irregularities. A MUC4 immunostain was performed on 5 specimens; all tested positive (100%). FUS rearrangement was detected in 4 out of 5 cases (80%). Follow-up information revealed 5-year recurrence in 1 case and metastatic disease in 2 cases, to the lung/pleura (8 years) and fourth rib (1 year), respectively.

CONCLUSIONS

The presence of bland spindle cells and associated with myxoid matrix material, in the appropriate clinical setting, can suggest LGFMS and direct additional confirmatory testing. A definitive diagnosis of LGFMS on FNA requires adequate sampling, familiarity with key cytomorphologic features, acquisition of diagnostic material for a cell block preparation and ancillary testing, and clinicoradiologic correlation.

Utility of Claudin-4 versus BerEP4 and B72.3 in pleural fluids with metastatic lung adenocarcinoma

INTRODUCTION

Lung adenocarcinoma (LADC) is the most common occult primary in patients presenting with a malignant pleural effusion. Distinguishing metastatic LADC from reactive mesothelial cells (RMC) and malignant mesothelioma (MM) based on morphology alone has been a persistent diagnostic challenge in cytopathology. Claudin-4, a major functional constituent of tight junctions, has been shown to help distinguish LADC from RMC and MM in surgical specimens. Our goal was to further validate and assess the utility of Claudin-4 in comparison to BerEP4 and B72.3 in malignant effusions with a focus on metastatic LADC.

MATERIALS AND METHODS

We evaluated 58 pleural effusions (40 LADC, 10 RCM, and 8 MM). Immunohistochemistry was performed using Claudin-4, Ber-EP4, and B72.3 on cell blocks. Staining patterns, quantity of tumor cells, and intensity of staining (weak, moderate, or strong) were assessed.

RESULTS

All cases of LADC were positive for Claudin-4 with an overall sensitivity of 100% (40 of 40) and specificity of 100% (18 of 18). In addition, Claudin-4 showed the highest quantity and quality of staining with 3+ staining intensity in 73% (29 of 40) of cases, compared with 35% (14 of 40) of cases using BerEP4 and 52% (21 of 40) of cases using B72.3. The sensitivity and specificity for BerEP4 were 90% and 78%, respectively. The sensitivity and specificity for B72.3 were 87.5% and 100%, respectively.

CONCLUSIONS

In this study, Claudin-4 performed superiorly compared to BerEP4 and B72.3 in distinguishing lung adenocarcinoma from RMC or MM in pleural effusions. Our results show Claudin-4 is a useful marker for distinguishing RMC and MM from lung adenocarcinoma, with high sensitivity (100%) and specificity (100%), compatible with studies shown in the literature.

Pulmonary sclerosing pneumocytoma: Cytomorphology and immunoprofile

BACKGROUND

Sclerosing pneumocytoma (SP) is a rare, benign pulmonary neoplasm. To the authors' knowledge, the current study is the first to evaluate the cytomorphology and immunoprofile of SP in a series.

METHODS

A total of 9 fine-needle aspiration cases of SP (7 of which were computed tomography guided and 2 of which were endobronchial ultrasound guided) including histopathology and immunohistochemistry were collected from 5 institutions.

RESULTS

The female-to-male ratio was 3.5:1, and the mean age of the patients was 54 years (range, 27-73 years). All cases presented as lung nodules, with a mean size of 2.2 cm (range, 1.1-5 cm), and were interpreted as atypical on rapid on-site evaluation. The final diagnoses were favor adenocarcinoma (1 case), well-differentiated lung adenocarcinoma (2 cases), low-grade epithelial neoplasm (2 cases), and sclerosing pneumocytoma (4 cases). Samples were moderately cellular, and consisted of round epithelioid cells with clear cell features, columnar cells, and spindle cells. A papillary arrangement with prominent hyalinized fibrovascular cores was the most common architectural pattern, followed by flat sheets and acinar formations. Tumor cells demonstrated mild, focally moderate nuclear pleomorphism with prominent nucleoli, hyperchromasia, nuclear elongation, nuclear overlap, and occasional nuclear inclusions and grooves. The background consisted of foamy macrophages (9 cases), hemosiderin pigment (6 cases), and lymphoid aggregates (3 cases) with no mitoses and/or necrosis. The surface cells and underlying round cells were positive for both thyroid transcription factor 1 and epithelial membrane antigen in all cases, which was the most notable immunohistochemical finding.

CONCLUSIONS

Cytomorphological findings of SP overlap with those of well-differentiated lung adenocarcinoma. Awareness of these cytomorphologic findings and the distinct immunoprofile of the 2 cell types found in SP should prevent a misdiagnosis and aggressive treatment.

Proceedings of the American Society of Cytopathology companion session at the 2019 United States and Canadian Academy of Pathology Annual meeting, part 2: effusion cytology with focus on theranostics and diagnosis of malignant mesothelioma

We live in the "era" of minimally invasive procedures, molecular testing, and personalized care. Effusions have a high sensitivity and will often yield diagnostic cytological material. The companion session presented by the American Society of Cytopathology at the 2019 United States and Canadian Academy of Pathology meeting outlined our current and future projected practices in characterizing, managing, and diagnosing serous cavity fluids. In this second part, the role of theranostics and the diagnosis of malignant mesothelioma, as was discussed at the meeting, have been highlighted. In theranostics, a vast amount of data has been reported regarding the epidermal growth factor receptor and related molecules. Some studies have also reported on HER2 immunohistochemistry and fluorescence in situ hybridization. This follows the most active areas of research in targeted therapy. Furthermore, during this session, malignant mesothelioma was extensively discussed. The cytologic diagnosis of malignant mesothelioma in effusion specimens has been controversial; however, a definitive diagnosis will be possible in many cases. Radiologic information should be sought, because the radiologist can often provide a definite or very likely diagnosis of malignancy. Microscopically, high cellularity and/or numerous balls of cells or papillary groups will favor the diagnosis of mesothelioma. It is important to exclude metastatic carcinoma with a broad-spectrum carcinoma marker, of which claudin-4 has been the best, because it will not cross react with mesothelioma. BAP1 and MTAP immunohistochemistry and CDKN2A fluorescence in situ hybridization are very useful adjunctive techniques for separating benign from malignant mesothelial proliferations. The use of 2 of these approaches together will produce a sensitivity of 80% to 90% for epithelial mesotheliomas in the pleura, although the sensitivity has been lower in the peritoneal cavity.

Insulinoma-associated protein 1 is a sensitive and specific marker for lung neuroendocrine tumors in cytologic and surgical specimens

INTRODUCTION

Insulinoma-associated protein 1 (INSM1) is an immunohistochemical marker for neuroendocrine differentiation with potentially superior sensitivity and specificity. INSM1 performance in pulmonary cytology cell block material (CB) has not been well established, and large series demonstrating its performance have been few.

MATERIALS AND METHODS

Typical and atypical carcinoid, small cell lung carcinoma, and large cell neuroendocrine carcinoma, squamous cell carcinoma, and adenocarcinoma CBs and 563 surgical specimens comprising 17 typical carcinoid, 14 atypical carcinoid, 8 small cell lung carcinoma, 10 large cell neuroendocrine carcinoma, 58 squamous cell carcinoma, 415 adenocarcinoma, and 17 large cell carcinoma cases and 24 other tumor types were immunostained with INSM1, CD56, synaptophysin, and chromogranin A.

RESULTS

The INSM1 sensitivity, specificity, positive predictive value, and negative predictive value were 92.3%, 100%, 78.9%, and 99% in the CBs and 89.8%, 98.1%, 81.5%, and 99% in the surgical specimens, respectively, with 86.2% concordance. The sensitivity, specificity, positive predictive value, and negative predictive value for the other neuroendocrine markers were 97.4%, 93.3%, 97.4%, and 93.3% in the CBs and 93.9%, 93.6%, 58.2%, and 99.4% in the surgical specimens for CD56; 89.7%, 100%, 100%, and 75% in the CBs and 93.4%, 91.2%, 50.5%, and 99.4% in the surgical specimens for synaptophysin; 66.7%, 100%, 100%, and 53.6% in the CBs and 75.5%, 98.6%, 84.1%, and 97.7% in the surgical specimens for chromogranin A, respectively. Finally, INSM1, together with CD56, maximized the sensitivity to 100% with 93.3% specificity in the CBs.

CONCLUSIONS

The results from our study have further established the high sensitivity and specificity of INSM1 in the largest pulmonary cytologic and surgical cohorts to date. INSM1 either matched or outperformed the performance of existing neuroendocrine markers, and its combination with CD56 appeared to maximize test performance.

Mucoepidermoid carcinoma, acinic cell carcinoma, and adenoid cystic carcinoma on fine-needle aspiration biopsy and The Milan System: an international multi-institutional study

BACKGROUND

We evaluated the diagnostic accuracy (DA), risk of neoplasm (RON), and risk of malignancy (ROM) for the commonly encountered malignant salivary gland tumors mucoepidermoid carcinoma (MECa), acinic cell carcinoma (ACCa), and adenoid cystic carcinoma (ADCa) applying The Milan System for Reporting Salivary Gland Cytology (MSRSGC).

MATERIALS AND METHODS

The cytology archives from 2007 to 2017 of 9 academic institutions were searched for salivary gland FNAs for the following key words mentioned either in the principal and/or differential diagnosis: MEC, ACCa, and ADCa. The original cytology diagnosis was retrospectively classified according to the MSRSGC. Patient demographics, biopsy site, and available surgical follow-up were recorded. The final analysis included only cases with surgical follow-up.

RESULTS

A total of 212 salivary gland FNAs were included. Based on retrospective reclassification according to MSRSGC, 97 of 212 (46%) FNA cases carried a diagnosis of malignancy specific for either MECa, ACCa, or ADCa. In the remaining 115 cases, 24 of 212 (11%) were reclassified as suspicious for malignancy (SM) and 91 of 212 (43%) as salivary gland neoplasm of uncertain malignant potential (SUMP). The DA for MECa, ACCa, and ADCa was 78.7%, 75% and 89%, respectively. The RON was 100% for all 3 tumors and the ROM was 93.6% for MECa, 96.8% for ACCa, and 94.4% for ADCa.

CONCLUSIONS

The DA of 78.7% for MECa, 75% for ACCa, and 89% for ADCa is reasonable in FNA specimens. Although the management of definitive cases of malignancy remains unchanged, the MSRSGC provides a ROM for SM and SUMP categories, which can improve patient management.

Importance of anal cytology and screening for anal dysplasia in individuals living with HIV with an emphasis on women

BACKGROUND

The incidence of squamous cell carcinoma of the anal canal has been increasing in high-risk populations. To the authors' knowledge, there is no international consensus regarding screening for squamous cell carcinoma of the anal canal, but screening is commonly comprised of a Papanicolaou (Pap) test in combination with digital anorectal examination followed by high-resolution anoscopy if necessary. The current study focused on individuals living with HIV and particularly on women living with HIV.

METHODS

In this 5-year retrospective study, the authors identified 5982 Pap tests, 1848 of which had follow-up biopsy within 6 months. The rate of atypical squamous cells of undetermined significance was 42%, and approximately 38.1% of cases with this interpretation were diagnosed as high-grade squamous intraepithelial lesions on follow-up biopsy. In addition, 82 women with anal cytology had long-term follow-up (>10 years) available.

RESULTS

The authors investigated a relationship between cervicovaginal human papillomavirus (HPV) results, cervical pathology, CD4 T-cell count, and CD4/8 ratio with the anal cytology interpretation. A statistical correlation was noted between the CD4 count and the CD4/8 ratio and the presence of anal dysplasia. Nearly one-half of the women without cervicovaginal HPV positivity presented with anal dysplasia.

CONCLUSIONS

The results of the current study demonstrated that, among women living with HIV, screening for anal dysplasia should not be eschewed, regardless of lower genital tract pathology and/or HPV status. To the authors' knowledge, the current study is the largest reported retrospective anal cytology cohort in individuals living with HIV.

Application of the Milan System for Reporting Submandibular Gland Cytopathology: An international, multi-institutional study

BACKGROUND

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a 6-tier diagnostic category system with associated risks of malignancy (ROMs) and management recommendations. Submandibular gland fine-needle aspiration (FNA) is uncommon with a higher frequency of inflammatory lesions and a higher relative proportion of malignancy, and this may affect the ROM and subsequent management. This study evaluated the application of the MSRSGC and the ROM for each diagnostic category for 734 submandibular gland FNAs.

METHODS

Submandibular gland FNA cytology specimens from 15 international institutions (2013-2017) were retrospectively assigned to an MSRSGC diagnostic category as follows: nondiagnostic, nonneoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SM), or malignant. A correlation with the available histopathologic follow-up was performed, and the ROM was calculated for each MSRSGC diagnostic category.

RESULTS

The case cohort of 734 aspirates was reclassified according to the MSRSGC as follows: nondiagnostic, 21.4% (0%-50%); nonneoplastic, 24.2% (9.1%-53.6%); AUS, 6.7% (0%-14.3%); benign neoplasm, 18.3% (0%-52.5%); SUMP, 12% (0%-37.7%); SM, 3.5% (0%-12.5%); and malignant, 13.9% (2%-31.3%). The histopathologic follow-up was available for 333 cases (45.4%). The ROMs were as follows: nondiagnostic, 10.6%; nonneoplastic, 7.5%; AUS, 27.6%; benign neoplasm, 3.2%; SUMP, 41.9%; SM, 82.3%; and malignant, 93.6%.

CONCLUSIONS

This multi-institutional study shows that the ROM of each MSRSGC category for submandibular gland FNA is similar to that reported for parotid gland FNA, although the reported rates for the different MSRSGC categories were variable across institutions. Thus, the MSRSGC can be reliably applied to submandibular gland FNA.

Ancillary Techniques in Cytologic Specimens Obtained from Solid Lesions of the Pancreas: A Review

Advanced methods of molecular characterization have elucidated the genetic, epigenetic, and proteomic alterations associated with the broad spectrum of pancreatic disease, particularly neoplasia. Next-generation sequencing, in particular, has revealed the genomic diversity among pancreatic ductal adenocarcinoma, neuroendocrine and acinar tumors, solid pseudopapillary neoplasm, and other pancreatico-biliary neoplasms. Differentiating these entities from one another by morphologic analysis alone may be challenging, especially when examining the small quantities of diagnostic material inherent to cytologic specimens. In order to enhance the sensitivity and specificity of pancreatic cytomorphology, multiple diagnostic, prognostic, and predictive ancillary tests have been and continue to be developed. Although a great number of such tests have been developed for evaluation of specimens collected from cystic lesions and strictures, ancillary techniques also play a significant role in the evaluation of cytologic specimens obtained from solid lesions of the pancreas. Furthermore, while some tests have been developed to differentiate diagnostic entities from one another, others have been developed to simply identify dysplasia and malignancy. Ancillary studies are particularly important in the subset of cases for which cytomorphologic analysis provides a result that is equivocal or insufficient to guide clinical management. Selection of appropriate ancillary testing modalities requires familiarity with both their methodology and the molecular basis of the pancreatic diseases for which testing is being performed.

Orthopedia homeobox protein (OTP) is a sensitive and specific marker for primary pulmonary carcinoid tumors in cytologic and surgical specimens

INTRODUCTION

Orthopedia homeobox protein (OTP) was recently demonstrated to be a pulmonary neuroendocrine marker showing specificity for pulmonary carcinoid tumors in histologic sections. Little is known of OTP performance and specificity for pulmonary neuroendocrine tumors in lung fine-needle aspiration (FNA) cell blocks (CBs), however.

MATERIALS AND METHODS

We evaluated OTP expression in lung non-neuroendocrine and neuroendocrine tumor CBs to determine its diagnostic utility in these specimens. Pulmonary typical carcinoid (TC) and atypical carcinoid (AC), small-cell lung cancer (SCLC) and large-cell neuroendocrine carcinoma (LCNEC), and squamous cell carcinoma (SQ) and adenocarcinoma (ADC) CBs were retrieved along with matched surgical cases and assessed for nuclear OTP expression with immunohistochemistry.

RESULTS

Nuclear OTP was seen in 82% TCs (9 of 11) and 83% ACs (10 of 12), but not in SCLC (0 of 9), LCNEC (0 of 9), SQ (0 of 10) or ADC (0 of 6) cytology cases. Similar to the cytologic specimens, nuclear OTP was seen in 82% TCs (9 of 11) and 80% ACs (8 of 10) but in none of the SCLC (0 of 8), LCNEC (0 of 7), SQ (0 of 8) or ADC (0 of 6) resections. Both AC and TC CBs showed a similar percentage of cells expressing nuclear OTP. By contrast, in resection specimens, 30% ACs (3 of 10) compared with 73% TC (8 of 11) cases showed >40% of cells nuclear OTP staining. Nuclear OTP demonstrated 80-83% sensitivity and 100% specificity for pulmonary carcinoid tumors in cytology and surgical specimens.

CONCLUSION

In the context of pulmonary malignancies, nuclear OTP immunohistochemistry is highly sensitive and specific in distinguishing carcinoid tumors from other pulmonary neuroendocrine and non-neuroendocrine malignancies in cytologic and surgical specimens.

Immunohistochemical staining for S100P, SMAD4, and IMP3 on cell block preparations is sensitive and highly specific for pancreatic ductal adenocarcinoma

INTRODUCTION

The diagnosis of pancreatic ductal adenocarcinoma (PDA) on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) material is often challenging. An immunohistochemical (IHC) panel may help establish the diagnosis of PDA in cases limited by sample size or ambiguous cytology. S100P, IMP3, and SMAD4 are 3 IHC markers that have shown promise as individual markers for PDA that have never been tested together as a panel. In this study, we evaluated the individual and combined efficacy of S100P, IMP3, and SMAD4 for the detection of PDA.

MATERIALS AND METHODS

S100P, IMP3, and SMAD4 IHC staining was performed on cell blocks (CBs) procured from pancreatic EUS-FNA procedures. The cohort included CBs that were diagnostic for PDA (n = 35), suspicious but nondiagnostic for PDA (n = 2), as well as CBs with benign pancreatic ductal epithelium (n = 12) and benign reactive pancreatic ductal epithelium (n = 18). A positive result for IMP3 and S100P was defined as moderate or strong staining of >10% of ductal cells. Complete lack of SMAD4 nuclear staining was considered a positive result-any nuclear SMAD4 staining was considered a negative result.

RESULTS

Two and 3 IHC marker panels were almost always more specific than individual IHC markers. Positivity for at least 2 of 3 IHC markers was a sensitive (91.89%) and highly specific (100%) marker of PDA.

CONCLUSIONS

The 3 IHC marker panel composed of S100P, IMP3, and SMAD4 is highly specific for PDA. Future studies should evaluate efficacy in a cohort with more atypical and suspicious cases.

HPV test result monitoring of different Bethesda categories in gynaecologic cytology: A valuable quality assurance measure

BACKGROUND

High-risk human papillomavirus (HPV) test ordering has evolved since the 2006 ASCCP guidelines. In light of the availability of the HPV test results for most women ≥30 y, regardless of the Pap test diagnosis; we examined their value in assessing the overall performance of cytopathologists (CPs).

METHODS

Data were derived for six CPs for Pap test interpretations over 4 y. HPV positivity rates for atypical squamous cells of undetermined significance (ASC-US) and for patients ≥30 y for negative for intraepithelial lesion or malignancy (NILM) and squamous intraepithelial lesion (SIL) (inclusive of low grade SIL (LSIL), high grade SIL (HSIL), and carcinoma) categories were retrieved for individual CPs. ASC/SIL ratios were analysed overall and separately for patient groups <30 y and ≥30 y. Pearson correlation coefficient was calculated to assess correlation between HPV positivity rates for ASC-US, NILM and SIL, and ASC/SIL ratios.

RESULTS

The overall ASC-US HPV positivity rate was 41%-49% for patients <30 y, 32% for patients ≥30 y. Stratifying by patient age group, ASC-US HPV positivity rate, and ASC/SIL ratio showed a negative correlation. Excluding an outlier, the NILM HPV positivity rate and ASC/SIL ratio showed a strong negative correlation.

CONCLUSION

Our study shows that ASC-US HPV positivity rate is dependent on the age of the population that is tested. Monitoring of the HPV positivity rates for NILM and SIL categories can serve as an additional objective measure to assess the performance of CPs. Based on the patient population, the laboratory can establish an initial baseline for these rates and use it to adjust interpretive thresholds in ensuring the diagnostic sensitivity of the test and the quality of the interpretation.

Immunohistochemical analysis of OTP and NKX6.1 in neuroendocrine tumors of the lung and pancreas

BACKGROUND

Homeobox transcription factors have demonstrated utility in diagnosing neuroendocrine tumors. Orthopedia homeobox protein (OTP) has a well-defined role in embryonic neurodevelopment and has also been described as a prognostic marker in lung neuroendocrine tumors (NET). Additionally, NK6 homeobox-1 (NKX6.1) has been described to be necessary for the development of neuroendocrine cells in the pancreas. We evaluated immunohistochemical (IHC) expression of OTP and NKX6.1 to determine their utility in the diagnosis of NETs from lung and pancreas fine-needle aspirations (FNA).

METHODS

Our study examined 50 FNA specimens, including 30 primary pulmonary NETs (8 carcinoid tumors (CT), 6 atypical carcinoids (AC), 11 small-cell neuroendocrine carcinomas (SCNEC), 5 large-cell neuroendocrine carcinomas (LCNEC)) and 20 primary pancreatic NETs (17 well-differentiated pancreatic neuroendocrine tumors (PanNET) and 3 poorly differentiated pancreatic neuroendocrine carcinomas (PanNEC)). IHC expression of OTP, NKX6.1, and Ki-67 was evaluated on FNA cell blocks.

RESULTS

Half of the pulmonary TC tumors expressed OTP, while only 17% of AC and 20% of LCNEC expressed OTP. Neither SCNECs nor any pancreatic NET expressed OTP. In contrast, intermediate and high-grade tumors expressed NKX6.1 (LCNEC-80%, SCNEC-82%, and AC-83%) more often than low-grade tumors (TC-63%, PanNET-71%). All three PanNECs expressed NKX6.1.

CONCLUSIONS

OTP may be useful in diagnosing well-differentiated NETs of pulmonary origin. NKX6.1 may have utility in segregating high from low-grade NETs of both pulmonary and pancreatic origin, although other methods will be required to determine site of origin.