The new guidelines of Papanicolaou Society of Cytopathology for respiratory specimens: Assessment of risk of malignancy and diagnostic yield in different cytological modalities

From sampling to cellblock: The fully automated journey of cytological specimens

In recent years, technological innovation have emerged to standardize pathology laboratory processes and reduce the handling of diagnostic samples. Among them is an automatic tissue embedding system that eliminates the need for manual activity in tissue paraffin embedding, thereby improving sample preservation. Unfortunately, this system cannot be used for cytological specimens due to the lack of an effective holder to support the procedure steps. In this study, we evaluated the performance of a commercial polymer matrix to enable and standardize the automatic paraffin embedding of cytological material from different organs and sources. Cytological samples from 40 patients were collected on the matrices and submitted for fully automatic workflow preparation, from formalin fixation until paraffin block, using the Sakura embedding system. Our results demonstrated the feasibility of the automated procedure, from loading cytological sample onto the matrix to obtaining the paraffin cellblock, thereby avoiding manual manipulation of cellular material. All samples resulted adequately processed and paraffin-embedded showing satisfactory tissue permeation by processing reagents, optimal preservation of cytoplasmic and nuclear details, and good quality of staining results on paraffin sections. Automated embedding of cytological samples eliminates the risk of lost specimens, reduces laboratory burden, standardizes procedures, increases diagnostic yield, and ultimately improves patients' management.

Evaluating the Risk of Malignancies of the Diagnostic Categories Proposed by the World Health Organization System for Reporting Lung Cytopathology: A 2-Year Single Institutional Experience

INTRODUCTION

The WHO System of Reporting Lung Cytopathology proposed a 5-tiered system in 2023. We report the risk of malignancies (ROMs) of bronchial washing/lavage and percutaneous fine-needle aspiration (FNA) specimens. We also evaluated the change of ROMs when image correlation is required.

METHODS

Lung cytology cases in 2021 and 2022 with histologic follow-up were included. CT reports were reviewed to identify cases with a solid nodule/tumor but benign cytological findings. These were reassigned from the "benign" to "non-diagnostic" category, and the ROMs were re-estimated.

RESULTS

A total of 1,031 bronchial washing/lavage and 206 FNAs were identified. The ROMs of bronchial washing/lavage were "non-diagnostic" 56.5% (13/23), "benign" 41.9% (320/764), "atypical" 71.7% (71/99), "suspicious for malignancy" 94.7% (72/76), and "malignant" 100% (70/70). The ROMs of FNAs were "non-diagnostic" 66% (33/50), "benign" 58.2% (39/67), "atypical" 70% (28/40), "suspicious for malignancy" 96.2% (25/26), and "malignant" 100% (70/70). When image finding was considered, cases initially assigned as "benign" were re-classified to "non-diagnostic" with decreases in ROMs for the "benign" category.

CONCLUSIONS

Malignancy risks associated with the WHO System of Reporting Lung Cytopathology diagnostic groups were reported. Image correlation for the "benign" category led to a decrease in case number and ROM.

Retrospective application of WHO reporting system for lung cytopathology with assessment of risk of malignancy

INTRODUCTION

The recently introduced World Health Organization (WHO) Reporting System for Lung Cytopathology presents 5 diagnostic categories with corresponding risk of malignancy (ROM) and management protocols. This study uses the system to categorize our institutional respiratory tract cytology specimens, evaluating ROM and diagnostic accuracy for each category.

MATERIALS AND METHODS

In a retrospective analysis (May 2020 to August 2021), the following respiratory cytology specimens were classified based on the WHO categories: bronchoalveolar lavage (BAL), bronchial wash/bronchial brushings (BB/BW), endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), fine-needle aspiration cytology (FNAC), sputum, biopsy imprint (BI), and endotracheal wash. Exclusions comprised pleural effusions and EBUS-TBNA from mediastinal and hilar lymph nodes. Correlation of cytologic and histopathologic diagnoses was performed to assess ROM collectively and individually.

RESULTS

A total of 1518 respiratory samples (BAL [968], BW/BB [380], EBUS-TBNA [42], FNAC [32], sputum [80], BI [11] and endotracheal wash [5]) of 1410 patients were screened, of which 522 cases (34.3%) had histopathologic correlation. One hundred forty-one cases (9.3%) were Insufficient/Inadequate/Non-Diagnostic (ND), 1221 (80.4%) were Benign (B), 3 (0.2%) were Atypical (A), 32 (2.1%) were Suspicious for malignancy (SM) and 121 (8.0%) were Malignant (M). The estimated ROM for each category was 49.2% for ND, 13.3% for B, 66.6% for A, 81.5% for SM and 92.7% for M. FNAC and EBUS-TBNA exhibited the highest sensitivity (100%) compared with BW/BB (66.3%). Specificity ranged from 96.8% to 100% across the samples, while diagnostic accuracy varied from 58.8% to 100%.

CONCLUSIONS

Application of the WHO reporting system enhances standardized terminology, aiding clinicians in informed decision-making and improving patient care through accurate risk assessment of malignancy.

Risk of malignancy assessment of the different cytologic categories in respiratory cytology samples according to the new guidelines of the Papanicolaou Society of Cytopathology

BACKGROUND

Cytology is extremely important for diagnosis of lung carcinoma and the Papanicolaou Society of Cytopathology (PSC) had proposed a new classification system for respiratory cytology for better communication between physicians and better patient management. The objective of this study is to analyze our samples in accordance with this classification and to evaluate the diagnostic accuracy of various cytologic techniques and to assess the risk of malignancy.

METHODS

Eight hundred and twenty respiratory cytology specimens (FNA, BAL, washing, brushing, sputum) collected between 2019 and 2022 were classified according to the PSC system and the risk of malignancy was assessed for each category using follow-up surgical samples. Sensitivity, specificity, and accuracy rates were determined based on a categorial approach, according to a similar study.

RESULTS

The data of 820 respiratory cytology specimens from 576 patients were analyzed. 2.6% of these were non-diagnostic, 64.1% were NM, 5% were AC, 0.4% were N-B-LG, 4% were SM and 23.9% were ML. The risk of malignancy for each diagnostic category were: 42.8% for non-diagnostic, 31.2% for NM, 43.9% for AC, 87.9% for SM, 94.3% for ML. Sensitivity and specificity was calculated using only the malignant cases considered as positive tests and was 45.57% and 97.34% respectively.

CONCLUSION

Our results correlated with the PSC system, and it was considered useful in clinical practice. However, more studies should be performed to evaluate the usefulness of this system. The ROMs of each category and the impact of different techniques should be further studied.

The rationale for the development and publication of the World Health Organization reporting systems for cytopathology and a brief overview of the first editions of the lung and pancreaticobiliary systems

The International Academy of Cytology has joined with the International Agency for Research on Cancer and the World Health Organization (WHO) to develop international systems for reporting the cytopathology of lung, pancreas and biliary tract, lymph nodes, soft tissue, liver, breast, and kidney and adrenal gland. The WHO recently published the reporting systems for lung and pancreaticobiliary cytopathology. The objectives of this collaboration are to standardize the reporting of cytopathology; improve the quality of reporting by establishing the key diagnostic cytopathological features of entities and neoplasms; provide detailed best-practice guidelines in sampling techniques, specimen handling and processing, and the use of ancillary techniques; and facilitate communication between cytopathologists and clinicians to improve patient care. Each WHO system has defined specific categories and terminology for reporting cytopathology, and each category has an estimated risk of malignancy as far as the current literature allows and a suggested diagnostic management algorithm to assist clinicians. The WHO systems recognize that local medical and pathology infrastructure will vary, particularly in low-income and middle-income countries, and the WHO systems and their diagnostic management recommendations have been developed to allow them to be applied worldwide in all resource settings. The process of the selection of editors and authors and the writing and editing responsibilities has used the same model as that used for the fifth edition WHO Classification of Tumours, to which the WHO cytopathology systems are directly linked. This review provides the rationale and history of this joint International Academy of Cytology, International Agency for Research on Cancer, and WHO cytopathology project and a brief overview of the WHO reporting systems for lung and pancreaticobiliary cytopathology.

Grey zones in respiratory cytology: Atypical or suspicious for malignancy and neoplasms of unknown malignant potential

The purpose of pulmonary cytology is two-fold. First, to establish whether a pulmonary nodule is benign or malignant. Second, pulmonary cytology should classify the type of pathologic process present. When a pulmonary nodule is characterized as malignant, it is of high importance to further classify the malignancy as to type, with non-small cell carcinomas being sub-divided into adenocarcinomas, squamous cell carcinomas, and other types of non-small cell carcinoma. The World Health Organization Reporting System for Lung Cytopathology (WHORSLC) provides an important framework for reporting and classifying material obtained by cytologic techniques, including sputum analysis, bronchial brushings, bronchial washings, and fine-needle aspiration. The system contains five categories for specimen reporting. Clinicians prefer definitive diagnoses separating specimens into definitively benign or definitively malignant categories. The WHORSLC recognizes that it is not invariably possible for cytopathologists to separate specimens into definitively benign or definitively malignant categories. The five categories of the WHORSLC recognize the spectrum of cytologic changes running from clearly benign to clearly malignant, which cytopathologists must place into diagnostically useful and reproduceable categories. The intermediate categories of "atypical" and "suspicious for malignancy" provide structured categories with stringent definitions, estimated malignancy risks, and suggested management and follow-up recommendations. In this way, the categories "atypical" and "suspicious for malignancy" aid in maintaining the high diagnostic accuracy of the "benign" and "malignant" categories.

A brief review of the WHO reporting system for lung cytopathology

The International Academy of Cytology has joined with the International Agency for Research on Cancer to bring together a group of experts in lung cytopathology to develop a WHO Reporting System for Lung Cytopathology (WHO System). This System aims to improve and standardize the reporting of cytopathology, facilitate communication between cytopathologists and clinicians, and improve patient care. The WHO System describes 5 categories for reporting lung cytopathology: 'Insufficient/Inadequate/Nondiagnostic', 'Benign', 'Atypical', 'Suspicious for malignancy', and 'Malignant', each one with a clear descriptive term, a definition, a risk of malignancy, and a suggested management algorithm. The key diagnostic cytopathologic features of each of the lesions within each category have been established by consensus through an Expert Editorial Board, who are also the authors of this review and selected for each reporting system and chosen based on their expertise in the field and/or diversity of geographical representation. Many other co-authors from around the world also contributed. The assignment of writing and editing responsibilities used the same model as that used for the WHO Classification of Tumours (https://whobluebooks.iarc.fr/about/faq/). The WHO System provides the best practice application of ancillary testing, including immunocytochemistry and molecular pathology, and guides in sampling and processing techniques to optimize the handling and preparation of specimens. The WHO System was created by the authors to be applicable globally and is based on cytomorphology with possibilities for additional diagnostic management of the patient. The authors are aware that local medical and pathology resources would differ, especially in low- and middle-income countries. The WHO Tumour Classification for Thoracic Tumors, Fifth Edition, is directly accessible through the online WHO System.

Comparison of small biopsy and cytology specimens: Subtyping of pulmonary adenocarcinoma

Objectives

The aims of this study was to investigate the use of cytologic samples for subclassification of lung adenocarcinoma and the cytologic-histologic correlation in lung adenocarcinoma subtypes using small samples.

Methods and Methods

Cytological characteristics of lung adenocarcinoma subtypes were summarized by a literature review. Cytology samples from 115 patients with lung adenocarcinoma confirmed by small biopsies were classified by subtype. The diagnostic concordance of subtypes between biopsy and cytology samples was assessed.

Results

Among the 115 cases, 62 (53.9%) had acinar predominant pattern, 16 (13.9%) were papillary predominant pattern, 29 (25.2%) had solid predominant pattern, 3 (2.6%) had lepidic predominant pattern, and 5 (4.3%) had micropapillary predominant pattern. All corresponding cytologic samples were classified into five subtypes based on cytomorphology features, with concordance rates of 74.2% (46 patients) in c-acinar subtype, 56.3% (nine patients) in c-papillary subtype, 24.1% (seven patients) in c-solid subtype, 66.7% (two patients) in c-lepidic subtype, and 40% (two patients) in c-micropapillary subtype. Collectively, the cytology and small biopsy concordance rate was approximately 57.4%.

Conclusion

Subtyping of lung adenocarcinoma using cytologic specimens is challenging and the consistency rate varies with the subtype. Acinar predominant tumors have an excellent cytologic-histologic correlation compared to tumors with predominant solid or micropapillary pattern. Evaluating cytomorphologic features of different lung adenocarcinoma subtypes can reduce the false-negative rate of lung adenocarcinoma, particularly for the mild, atypical micropapillary subtype, and improve diagnostic accuracy.

Accuracy of Bronchial Cytological Diagnosis in Lung Lesions in Comparison with Histopathology

The incidence of lung cancer has been increasing in the recent years. Bronchial cytology using Papanicolaou society of cytopathology (PSC) system is an effective method for triaging patients. The present study attempts to evaluate the bronchial cytological diagnosis with histopathological correlation of lung lesions.

Aims

i. To study the cytological features of lung lesions. ii. To assess the sensitivity, specificity, and diagnostic accuracy of bronchial cytology of lung lesions in comparison with histopathology.

Settings and Design

Prospective study at the tertiary care hospital.

Methods and Material

It included 63 cases of lung lesions, evaluated using the PSC system for reporting respiratory cytology. The cytological diagnosis was correlated with the final histopathological diagnosis. The study was conducted between January 2019 and June 2020.

Statistical Analysis Used

SPSS 20.0 software.

Results

The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of bronchial cytology was 60%, 89%, 90%, 58.62%, and 71.42%, respectively.

Conclusions

Bronchial cytology including bronchial wash, bronchial brush, endobronchial ultrasound/transbronchial needle aspiration, and computerized tomography-guided fine needle aspiration cytology can be used to increase the sensitivity and specificity for definitive diagnosis and better management.

Cytology Reporting System for Lung Cancer from the Japan Lung Cancer Society and the Japanese Society of Clinical Cytology: An Extensive Study Containing More Benign Lesions

INTRODUCTION

The Japan Lung Cancer Society (JLCS) and the Japanese Society of Clinical Cytology (JSCC) have proposed a new four-tiered cytology reporting system for lung carcinoma (JLCS-JSCC system). Prior to the proposal, the Papanicolaou Society of Cytopathology (PSC) had proposed a revised reporting system (PSC system), which comprises the "neoplastic, benign neoplasm, and low-grade carcinoma" category (N-B-LG category), in addition to the 4 categories of the JLCS-JSCC system. This study aimed to evaluate the interobserver agreement of the JLCS-JSCC system with an additional dataset with more benign lesions in comparison with the PSC system.

METHODS

We analyzed 167 cytological samples, which included 17 benign lesions, obtained from the respiratory system. Seven observers classified these cases into each category by reviewing one Papanicolaou-stained slide per case according to the JLCS-JSCC system and PSC system.

RESULTS

The interobserver agreement was moderate in the JLCS-JSCC (k = 0.499) and PSC (k = 0.485) systems. Of the 167 samples, 17 samples were benign lesions: 7 pulmonary hamartomas, 5 sclerosing pneumocytomas, 2 squamous papillomas, one solitary fibrous tumor, one meningioma, and one lymphocytic proliferation. There were diverse sample types as follows: 11 touch smears, 3 brushing smears, 2 aspirations, and one sputum sample. Fourteen samples (82.3%) were categorized into "negative" or "atypical" by more than half of the observers in the JLCS-JSCC system. Conversely, 3 samples were categorized as "suspicious" or "malignant" by more than half of the observers in the JLCS-JSCC system. On the other hand, 11 samples (64.7%) were categorized into the N-B-LG category by more than half of the observers in the PSC system.

CONCLUSIONS

The concordance rate in the JLCS-JSCC system was slightly higher than that in the PSC system; however, the interobserver agreement was moderate in both the JLCS-JSCC and PSC systems. These results indicate that both the JLCS-JSCC and PSC systems are clinically useful. Therefore, both systems are expected to have clinical applications. It may be important to integrate the 2 systems and construct a universal system that can be used more widely in clinical practice.

Atypia in pulmonary cytology: Morphologic spectrum and causes

BACKGROUND

The term "atypical" has had a long history of usage in cytology but has had variable definitions and usage. Most commonly the term was used to indicate a degree of cytomorphologic abnormality greater than that clearly due to reactive or reparative changes but not associated with a high concern on the part of the cytopathologist that a malignancy is present. The Papanicolaou Society of Cytopathology System for Reporting Respiratory Cytology provided a foundation for using the category "Atypical" along with the category "Suspicious for Malignancy" to categorize the spectrum of morphologic changes ranging from those which are clearly benign to those that are clearly malignant. The two intermediate categories of "Atypical" and "Suspicious for Malignancy" have characteristic recommendations resulting in clinical utility for both categories.

CONCLUSION

The Papanicolaou Society of Cytopathology System for Reporting Respiratory Cytology represents a useful system with defined intermediate categories of Atypical and Suspicious for Malignancy.

A modified Papanicolaou Society of Cytopathology system for reporting respiratory cytology specimens: Implications for estimates of malignancy risk and diagnostic accuracy

BACKGROUND

In 2016, the Papanicolaou Society of Cytopathology (PSC) proposed a classification scheme for reporting cytologic specimens obtained from the respiratory system. Diagnostic sensitivity, specificity, and risk of malignancy were reported for endobronchial ultrasound guided fine needle aspiration but data for other sampling techniques has been poorly documented.

METHODS

In 2016, a modified version of the PSC guidelines was adopted at the University of Missouri for classification of sputum, bronchial washing, bronchial brushing, and fine-needle aspiration specimens. Specimens assigned to the negative category included all specimens containing evaluatable inflammatory or epithelial cells including benign appearing respiratory epithelium. Only specimens with marked artifactual distortion or obscuring blood or mucus were placed in the non-diagnostic category.

RESULTS

672 bronchial washing specimens (479 with histology) and 511 bronchial brushings specimens (324 with histology) were reviewed. Washing specimens were classified as non-diagnostic (3%), benign (73%), atypical (10%), suspicious (4%), and malignant (10%). Bronchial brushing specimens were classified non-diagnostic (0.4%) benign (73%), atypical (6%), suspicious (3%), and malignant (17%). Malignancy risks for bronchial washings were insufficient (50%), benign (38%), atypical (62%), suspicious (83%), and malignant (98%). Risks of malignancy for bronchial brushings were insufficient (0%), benign (32%), atypical (79%), suspicious (75%), and malignant (94%).

CONCLUSION

Malignancy risks associated with bronchial washings and bronchial brushings are different than those reported for EBUS FNA. When the benign category includes specimens with "normal" appearing cellular elements, the risk of malignancy is substantial (between 32% and 38%).

Current Topics and Practical Considerations of Cytology Practice in Lung Cancer: Reflexions from the Lung Symposium at the 42nd European Congress of Cytology, Malmö, 2019

In June 2019, a lung symposium was held at the 42nd European Congress of Cytology in Malmö, Sweden. Due to the current importance of cytological samples in the diagnoses and molecular analysis to set up the utmost management of lung cancer patients, cytologists from different countries shared the experience of their institutions. The place of the cytological samples gains more and more importance on the potential long-term survival gain through personalized medicine and this harbors the improvement of the guidelines both in pathology and cytology field. In this symposium, the new 6-tiered reporting system for pulmonary cytology proposed by the Papanicolaou Society of Cytopathology and detailed cytomorphological approach to lung carcinoma including lookalike lesions and DNA- and RNA-based analysis of cytology material have been discussed. The cytopathologist plays a pivotal role in ensuring success of a correct triage for the cytology material to be sure of the adequacy and quality of the yield from the rapid on-site evaluation till the report which should encompass molecular profile in rational patient management.

Cytology Reporting System for Lung Cancer from the Japan Lung Cancer Society and Japanese Society of Clinical Cytology: An Interobserver Reproducibility Study and Risk of Malignancy Evaluation on Cytology Specimens

INTRODUCTION

The classification of lung carcinoma is based on small biopsies and/or cytology in 80% of patients with non-small cell carcinoma. However, there is no widely accepted classification system for respiratory cytology. The Japan Lung Cancer Society (JLCS) and Japanese Society of Clinical Cytology (JSCC) have proposed a new four-tiered cytology reporting system for lung carcinoma with the following categories: (1) "negative for malignancy," (2) "atypical cells," (3) "suspicious for malignancy," and (4) "malignancy."

OBJECTIVE

The aim of this work was to perform an interobserver reproducibility study to confirm the utility of the four-tiered reporting system on respiratory cytological samples.

METHODS

We analyzed 90 cytological samples obtained with bronchoscopy. Seven observers classified these cases into each category by reviewing one Papanicolaou-stained slide per case according to the three-, four-, and five-tiered reporting systems.

RESULTS

The interobserver agreement was fair in the three- (κ = 0.50), four- (κ = 0.45), and five-tiered (κ = 0.45) reporting systems. However, the four-tiered reporting system provided more precise information than the three-tiered reporting system in patient management. The risk of malignancy in the four-tiered reporting system was also stratified well: 19.3% for "negative for malignancy," 45.6% for "atypical cells," 74.7% for "suspicious for malignancy," and 88.1% for "malignancy."

CONCLUSIONS

The reporting system proposed by the JLCS and JSCC was designed to enhance the communication between clinicians and pathologists and among different institutions. It is simple and applicable to cytological diagnosis of any respiratory diseases. We propose establishing an international classification for respiratory cytology, harmonizing the reporting systems proposed by different countries.

Cytologic features and diagnostic value of PeriView FLEX transbronchial needle aspiration targeting pulmonary nodules

BACKGROUND

Transbronchial needle aspiration (TBNA) of peripheral lung nodules can be difficult with conventional devices due to their limited flexibility. A promising new technology for accessing these lesions is the PeriView FLEX TBNA device, which has a flexible spiral-grooved needle. The present study reports the unique cytologic features, diagnostic value, and potential pitfalls of PeriView FLEX TBNA specimens.

METHODS

This study retrospectively evaluates 113 consecutive cases of lung nodules sampled using the PeriView FLEX device with radial endobronchial ultrasound guidance.

RESULTS

PeriView FLEX specimens were satisfactory for evaluation in 111 of 113 cases (98%). A diagnosis of malignancy was made on 64 specimens (57%), with 100% specificity and 70% sensitivity for malignancy. In 4 cases, the PeriView FLEX sample was the only specimen from bronchoscopy that was diagnostic of malignancy. Of the 64 PeriView FLEX specimens with malignant cells, 58 (91%) were adequate for immunohistochemistry and 44 (69%) were adequate for molecular genetic testing. Potential pitfalls were largely ameliorated through education regarding the unique features of PeriView FLEX samples, such as the expected abundance of anthracotic pigment and the paucity of lymphocytes.

CONCLUSIONS

TBNA using the PeriView FLEX device to sample pulmonary nodules contributed to the diagnostic value of bronchoscopy and tended to provide sufficient tissue for ancillary studies. Many of the possible pitfalls may be avoided through consideration of the unique cytologic features associated with this novel sampling method.

The relevance of bronchoalveolar lavage fluid analysis for lung cancer patients

Introduction: Lung cancer is a serious malignant disease with poor prognosis. The methods for improving early recognition and markers of predictive value are widely investigated. Bronchoalveolar lavage (BAL) is a valuable method of respiratory tract investigation. Currently, BAL is rarely used for tumor diagnosis, but for ruling out differential diagnosis, due to its poor sensitivity. The new indication for BAL fluid analysis is evaluation of local immune reaction in lung cancer patients and description of tumor microenvironment (TME). A literature search was performed in bibliography bases from the time of the introduction of BAL in the diagnosis of lung diseases. We analyzed our prior original studies with the bibliography.Area covered: The usefulness of BAL in the diagnosis of peripheral spread of malignant diseases and in the evaluation of TME in lung cancer, as well as a role of BAL in the diagnosis of checkpoint inhibitor pneumonitis is presented. Commentary concerning methodology of BALF analysis in lung cancer is included.Expert opinion: It seems that in the near future BAL will find an important place in the evaluation of lung cancer TME in two aspects. The first could be characteristic of immune reaction by analysis of immune cells and mediators and the second cancer molecular characteristic by free DNA and exosomes analysis.