Digital Examination of LYmph node CYtopathology Using the Sydney system (DELYCYUS): An international, multi‐institutional study
Alessandro Caputo, Filippo Fraggetta, Pasquale Cretella, Immacolata Cozzolino, Albino Eccher, Ilaria Girolami, Stefano Marletta, Giancarlo Troncone, Elena Vigliar, Gennaro Acanfora, Karen Villar Zarra, Héctor Enrique Torres Rivas, Guido Fadda, Andrew Field, Ruth L. Katz, Philippe Vielh, Catarina Eloy, Arvind Rajwanshi, Nalini Gupta, Mousa A. Al‐Abbadi, Nadwa Bustami, Tala Ar’ar, Maria Calaminici, Juliet I. Raine, Helena Barroca, Pedro Amoroso Canão, Mats Ehinger, Nilofar Rajabian, Pranab Dey, L. Jeffrey Medeiros, Siba El Hussein, Oscar Lin, Antonio D’Antonio, Beata Bode‐Lesniewska, Esther Diana Rossi, Pio Zeppa
Abstract
BACKGROUND: After 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. METHODS: The 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. RESULTS: Overall, 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. CONCLUSIONS: The Sydney system for reporting lymph node cytopathology shows adequate interobserver concordance. Digital microscopy is an adequate means to assess lymph node cytopathology specimens.