EBUS-TBNA: A 2-Year Experience from a Tertiary Pathology Centre with Cyto-Histological Correlation

Endobronchial ultrasound-guided transbronchial fine needle aspiration of mediastinal lymphadenopathy: Diagnostic performance and clinical implications of the World Health Organization reporting system

INTRODUCTION

Lymph node fine-needle aspiration cytology (LN-FNAC) is a common, rapid, minimally invasive and cost-effective diagnostic method. For mediastinal lymph nodes, endobronchial ultrasound (EBUS) guided LN-FNAC is a first-line investigation and has an indispensable role in the diagnosis and staging of patients with suspected lung cancer. Recently, a new WHO system has been proposed for classification of LN-FNAC heralding five different diagnostic categories; insufficient, benign, atypical, suspicious for malignancy and malignant. The aim of this study was to evaluate the diagnostic accuracy and risk of malignancy (ROM) of these categories in EBUS-guided LN-FNAC from mediastinal lymph nodes.

METHOD

We evaluated 2110 consecutive mediastinal lymph nodes during this one-year retrospective study. Corresponding radiological images and histologic material were used as ground truth to calculate accuracy, sensitivity, specificity and ROM.

RESULTS

The WHO system showed an overall accuracy of 93.7% with a sensitivity of 83.0% and a specificity of 97.5%. The positive predictive value was 92.3% and the negative predictive value 94.2%. The overall ROM for each category in the WHO classification system was 12.8% for the inadequate, 2.4% for the benign, 47.4% for the atypical, 81.0% for the suspicious for malignancy and 93.6% for the malignant category.

CONCLUSION

The results of the present study indicate that the new WHO system entails a high diagnostic accuracy regarding EBUS-guided LN-FNAC assessment of mediastinal lymph nodes and supports its integration into clinical practice. Application of the WHO system standardizes risk assessment thus facilitating communication between cytopathologists and clinicians and minimizes the need for histopathological analysis.

The Diagnostic Value of Endobronchial Ultrasound-Guided Fine Needle Aspiration (EBUS-FNA) in Diagnosing FDG-PET-Avid Lymph Nodes in Extrapulmonary Malignancies

Background and objective The accurate diagnosis of extrapulmonary malignancies with mediastinal lymphadenopathy is crucial for effective patient management. Endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) has emerged as a valuable tool in assessing fluorodeoxyglucose (FDG)-positron emission tomography (PET)-avid lymph nodes (LNs). In this study, we aimed to evaluate the diagnostic value of EBUS-FNA in patients with mediastinal lymphadenopathy in extrapulmonary malignancies and compare its efficacy with PET-CT.  Methodology This retrospective, cross-sectional study was conducted at Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, from February 2018 to February 2023. It included patients with extrapulmonary malignancies with mediastinal lymphadenopathy displaying abnormal PET-CT uptake, with LN diameters ≥5 mm, excluding lung cancer cases. Data on demographics, malignancy type, LN involvement, PET-CT findings, and EBUS-FNA histopathology were collected. EBUS-FNA procedures involved a 22-gauge needle, and samples were analyzed cytologically and histologically. SPSS Statistics version 20 (IBM Corp., Armonk, NY) was used to perform the statistical analysis. Results The study analyzed a total of 216 patients. Males comprised 56.3% of the cohort, and females 43.7%. The most common malignancy was lymphoma (33.0%), followed by breast cancer (12.6%). EBUS-FNA exhibited a sensitivity of 90.9% compared to PET-CT's sensitivity of 72.7%. Lymph node morphology on EBUS showed low echogenicity and irregular borders in malignant cases. Subcarinal and right hilar were the most frequently sampled lymph nodes. The study found significant differences in lymph node characteristics between non-malignant and malignant groups, with EBUS-FNA effectively identifying malignancies.  Conclusions EBUS-FNA demonstrates high sensitivity and diagnostic utility in identifying malignant lymph nodes in patients with extrapulmonary malignancies. Its effectiveness in detecting true positive cases highlights its importance as a complementary diagnostic tool to PET-CT in oncological diagnostics.

Multi-Tissue Controls and Multiplex Immunocytochemistry in Pulmonary Cytology

INTRODUCTION

The World Health Organization 2021 lung cancer classification highlights the central role of immunohistochemistry (IHC) in diagnostic pathology. Despite traditional IHC being essential, its limitation to one marker per tissue section brings challenges, particularly when facing cytological limitedly sized samples. To overcome these challenges, multiplex immunocytochemistry (mICC) techniques offer the simultaneous detection of multiple markers from a single section. These advances complement the highly complex imaging techniques that enable additional analyses of cellular interactions.

METHODS

The present study outlines a comprehensive mICC methodology of an automated multiplex immunoperoxidase staining method and multiple tissue hybrid controls for ICC/mICC. Protocols are presented in detail and demonstrate a careful approach to optimizing various markers for diagnostic workup including immunotherapy.

CONCLUSION

Multiplex IHC/ICC emerges as a transformative force in biomedical diagnostics and research. Beyond simultaneous marker detection, it unravels complexities within tissues - unveiling co-localization nuances, deciphering expression patterns, and enhancing understanding of cellular populations. As personalized treatments gain prominence, the study emphasizes the heightened importance of diagnostic tools and sample adequacy. The present methodological study, encapsulating an automated multiplex immunoperoxidase staining method, symbolizes a stride towards precision in pulmonary carcinoma diagnosis. Multi-tissue controls represent a key element in quality assurance in pathology laboratories.

Utility of SHOX2 and RASSF1A gene methylation detection on the residual cytology material from endobronchial ultrasound-guided transbronchial needle aspiration

Objective

This study aims to assess the effectiveness of Short Stature Homeobox 2 (SHOX2) and RAS Association Domain Family 1 Isoform A (RASSF1A) gene methylation detection in residual liquid-based cytology (LBC) materials from Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) and investigate the diagnostic accuracy of a comprehensive diagnostic approach.

Material and Methods

Between June 2022 and May 2023, a total of 110 cases that underwent EBUS-TBNA were enrolled in the study. SHOX2 and RASSF1A genes methylation detection using the residual cytological material, LBC, and cell block (CB) were conducted for each EBUS-TBNA case. The sensitivity and specificity of cytology, CB histopathology, SHOX2, and RASSF1A methylation in diagnosing EBUS-TBNA samples were determined based on follow-up data.

Results

Among the 72 cases confirmed as pulmonary carcinomas, the methylation test yielded positive results in 24 adenocarcinoma cases, 10 squamous cell carcinoma cases, and 14 small cell carcinoma cases. The sensitivity of the comprehensive diagnosis (combining LBC, CB, and methylation detection) in distinguishing metastatic pulmonary epithelial malignancies in mediastinal and hilar lymph nodes or masses from benign lesions was higher (97.22%, 70/72) than that of morphological diagnosis alone (LBC and CB) (88.89%, 64/72; P < 0.05).

Conclusion

SHOX2 and RASSF1A methylation detection demonstrates a high sensitivity and negative predictive value in the identification of pulmonary epithelial malignancies and holds promise as a valuable ancillary approach to enhance morphological diagnosis of EBUS-TBNA.

Insufficient endobronchial ultrasound-guided transbronchial needle aspiration specimens. When and why? The analysis of criteria and reasons behind the insufficient specimens

BACKGROUND

The classification terminology systems for pulmonary cytology specimens have recently emerged. Inadequate samples, classified as "nondiagnostic," raise challenges in determining the threshold of cell numbers and the risk of malignancy (ROM).

METHODS

The study retrospectively reviewed 248 endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples: 46 insufficient samples, 60 low cellularity samples, and 142 adequate samples. Characteristics as cellularity, number of benign and malignant cells, and background features were assessed. Receiver operating characteristic curve analysis was performed to establish cell sufficiency thresholds for the diagnosis.

RESULTS

Out of the 248 samples analyzed, 108 were classified as benign, 94 as malignant, and 46 as insufficient. The study found that the cellularity thresholds for diagnosis in cell blocks and cytological samples were ≥50 cells and ≥100 cells, respectively. The thresholds for tumor cell counts were ≥1 - 10 cells for both types of cells, respectively. Considerably, some low cellularity samples were initially classified as insufficient despite meeting the diagnostic thresholds upon revision. The ROM varied across sample categories, with insufficient samples having a ROM of 10.9%, benign samples 15.7%, suspicious samples 92.0%, and malignant samples 100%.

CONCLUSION

Insufficient EBUS-TBNA samples raise challenges in diagnosis and management. This study identified the root cause of insufficient samples, including factors related to humans, diagnostic methods, sampling, and laboratory processing. By understanding the root causes, diagnostic recommendations can be developed to improve the diagnostic process. The findings emphasize the importance of standardized classification and terminology systems for clear communication among healthcare professionals and institutions, ultimately improving patient care and enabling quality assurance measures.