Background: The Sydney system has been proposed as a uniform format for reporting lymph node cytopathology under five standardised categories: Non-Diagnostic (ND), Benign (B), Atypical (Cells) of Undetermined Significance/Atypical Lymphoid (Cells) of Uncertain Significance (AUS/ALUS), Suspicious for Malignancy (SFM), and Malignant (M). Very few studies have been conducted so far to confirm the risk of malignancy (ROM) of the different categories. The main objectives of our study were to classify lymph node aspirates according to the proposed Sydney system and assess the ROM and other performance parameters.
Materials and methods: All lymph node aspirates done at our centre from January 2018 to December 2020 were reclassified according to the Sydney system. Using histopathological diagnosis as gold standard, ROM and performance parameters were calculated.
Results: A total of 1205 lymph node aspirates were reclassified: 53 (4.4%) ND, 488 (40.5%) B, 10 (0.8%) AUS/ALUS, 275 (22.8%) SFM, and 379 (31.5%) M. The ROM for each category was 9.1%, 1.5%, 37.5%, 96.9%, and 98.2%, respectively. The highest sensitivity was achieved when AUS/ALUS, SFM, and M were considered positive for malignancy, whereas maximum diagnostic accuracy was observed when only SFM and M were considered positive.
Conclusion: The Sydney system is an excellent system for accurately categorising lymph node aspirates with greater reproducibility of reports and better patient management through improved communication between cytopathologist and clinician.
Keywords: Sydney system; accuracy; lymph node aspirates; risk of malignancy.
© 2021 John Wiley & Sons Ltd.