Diagnostic Utility of Fine-Needle Aspiration Cytology in Patients with Lymphadenopathy in a Brazilian Tertiary University Hospital

Abstract

Objective: To determine the most frequent cytological patterns identified by fine-needle aspiration cytology (FNAC) of lymph nodes and analyze their association with demographic variables in patients evaluated at a Brazilian university hospital. Methods: Retrospective, observational, and descriptive study based on 1,527 cytopathology reports of lymph node FNAC performed between 2008 and 2025. Cytological findings were analyzed according to demographic variables using descriptive and inferential statistics. Results: Among the 1,527 cases, 54% were male and 46% female, with predominance of individuals aged 18-65 years. The most frequent cytological diagnosis was reactive lymphadenitis (33%), metastatic neoplasm (27%), undetermined chronic granulomatous lymphadenitis (7.7%), non-Hodgkin’s lymphoma (4.2%), atypical lymphoid proliferation (3.9%), chronic granulomatous lymphadenitis with acid-fast bacilli (AFB) positive (2.8%), and acute suppurative lymphadenitis (2.7%). Reactive lymphadenitis was associated with patients aged 0-17 years and cervical nodes (p < 0.0001). Metastatic neoplasms were associated with older age and supraclavicular, infraclavicular, and axillary nodes (p ≤ 0.001). Atypical lymphoid proliferation was associated with adolescents and elderly patients, and supraclavicular and inguinal nodes (p ≤ 0.003).  Granulomatous lymphadenitis was associated with ages 18-64 years (p = 0.005). Conclusion: Fine needle aspiration cytology (FNAC) proved to be an effective diagnostic tool, with 90% adequacy and 72% of cases resolved without additional tests. Reactive and metastatic patterns predominated, while para coccidioidomycosis was the most frequent fungal etiology. The low detection rate of tuberculosis highlights the need to incorporate culture and molecular methods into the same workflow to improve diagnostic yield.