Lymph node cytology Demystified: The Sydney System Lexicon

Introduction-Lymph node cytology has been a cornerstone in the diagnostic evaluation of various lymphadenopathies. However, the absence of a universally accepted classification system has led to inconsistencies in reporting, diagnostic ambiguity and challenges in clinical management decisions. The Sydney system of classification, a comprehensive framework designed to standardise the reporting using clear categories and criterion can enable the pathologists to provide more reliable and uniform reports. Aims and Objective- To classify the lymph node cytology lesions according to Sydney system of classification and to analyse the risk of malignancy in each category. Material and method- This is a 1.5 years single institute retrospective study done in department of Pathology. Cytology slides of lymph node lesions were retrieved and classified according to the Sydney classification. Histopathological correlation was made where ever possible. Statistical analysis was done using SPSS software. Results- A total 210 lymph node cytology lesions were classified by Sydney system of classification which showed Benign category (L2) was the commonest (56.2%) followed by malignant category(L5) which was 33.8%. Other categories were Inadequate (L1) 5.7%, AUS/ALUS (L3) 1%, Suspicious (L4) 3.3%. 26 cases had histopathological correlation. Diagnostic accuracy of 100% and both L4 and L5 category showed 100% risk of malignancy. Conclusion- This retrospective study classified 210 lymph node FNAs using The Sydney System. It found male predominance and cervical nodes as the most common site. Crucially, the study demonstrated a 100% diagnostic accuracy and 100% risk of malignancy for suspicious (L4) and malignant (L5) categories, highlighting The Sydney System's vital role in standardizing reporting and guiding patient management, despite a limited number of histopathological correlations