Digital Examination of LYmph node CYtopathology Using the Sydney system (DELYCYUS): An international, multi‐institutional study

Abstract

BackgroundAfter a series of standardized reporting systems in cytopathology, the Sydney system was recently introduced to address the need for reproducibility and standardization in lymph node cytopathology. Since then, the risk of malignancy for the categories of the Sydney system has been explored by several studies, but no studies have yet examined the interobserver reproducibility of the Sydney system.MethodsThe authors assessed interobserver reproducibility of the Sydney system on 85 lymph node fine‐needle aspiration cytology cases reviewed by 15 cytopathologists from 12 institutions in eight different countries, resulting in 1275 diagnoses. In total, 186 slides stained with Diff‐Quik, Papanicolaou, and immunocytochemistry were scanned. A subset of the cases included clinical data and results from ultrasound examinations, flow cytometry immunophenotyping, and fluorescence in situ hybridization analysis. The study participants assessed the cases digitally using whole‐slide images.ResultsOverall, the authors observed an almost perfect agreement of cytopathologists with the ground truth (median weighted Cohen κ = 0.887; interquartile range, κ = 0.210) and moderate overall interobserver concordance (Fleiss κ = 0.476). There was substantial agreement for the inadequate and malignant categories (κ = 0.794 and κ = 0.729, respectively), moderate agreement for the benign category (κ = 0.490), and very slight agreement for the suspicious (κ = 0.104) and atypical (κ = 0.075) categories.ConclusionsThe Sydney system for reporting lymph node cytopathology shows adequate interobserver concordance. Digital microscopy is an adequate means to assess lymph node cytopathology specimens.

Introduction of the WHO Reporting System for Lymph Node Cytopathology

“…The WHO Reporting System for Lymph Node Cytopathology plays a crucial role in standardizing nomenclature and reporting systems in cytopathology. 13 It facilitates the integration of diagnostic and management algorithms, assisting clinicians in effectively managing patients. Through international consensus, it establishes key diagnostic criteria in cytopathology, improving the quality of diagnostic assessment and reporting in lymph node cases.…”

Systematic Review and Meta-Analysis of the Diagnostic Accuracy of the Sydney System for Reporting Lymph Node Fine-Needle Aspiration Biopsy in Diagnosing Malignancy

“…One of the problems of the Sydney system is its reproducibility in different labs. A recent study by Caputo et al [15] evaluated the digital examination of lymph node cytopathology using the Sydney system. The overall interobserver concordance was moderate (Fleiss κ = 0.476).…”

Combined fine needle aspiration cytology and core needle biopsy in the same setting: A two‐years’ experience

“…Cell blocks were prepared for non-lymphomatous pathologies requiring ancillary studies. FNAC diagnoses were classified based on specific classification systems for lymph nodes 33,34 and thyroid, 6 while other targets were classified as negative, suspicious or positive for malignancy. Positive cases, when possible, were further specified by histotype, characterized using specific cytological features and ICC and FC techniques.…”