Fine Needle Aspiration Cytology of Lymph Nodes in Metastatic Cancer and Lymphoma: Our Single-institution Experience

Background: Lymphadenopathy is a common finding in clinical practice. The cause of enlarged nodes on clinical examination alone is challenging and there may be multiple reasons for this enlargement. It may become enlarged due to stimulation by infectious agents or the involvement of metastasis or malignant diseases, such as lymphoma. Objective: The aim of the study was to investigate the diagnostic role of fine needle aspiration cytology of lymph nodes in metastatic cancer and lymphoma. Methods: A total of 48 FNAC lymph nodes suspicious for malignancy were sampled with follow-up biopsy in Clinical Center of University of Sarajevo from 2017 to 2023. Lymph nodes were aspirated using 20-22 G needle with minimally 2 passes, spread on slides, air-dried, stained with May-Grünwald-Giemsa or Papanikolaou and residual material sent for cytoblock. Results: Out of 48 cytological samples, 30 (62.5%) revealed metastatic epithelial cells and 12 (25%) lymphoproliferative neoplasm. Three samples were suspected for malignancies, one sample was unrepresentative, one inconclusive and one falsely negative. Histopathological confirmation had 35 patients, while others were confirmed based on clinical presentation and radiological techniques. Compared to histopathological diagnosis, cytology had a sensitivity of 89.47%, specificity of 93.33%, positive predictive value (PPV) 95.04% and negative predictive values (NPV) 86.13% for epithelial metastatic cancer. The overall diagnostic test accuracy was 91.06%. For lymphoproliferative neoplasms cytology in comparison to histopathology had sensitivity 85.71%, specificity 91.18%, PPV 76.4% and NPV 95.04%. The overall diagnostic test accuracy was 89.81%. In both ways cytology is showing significant possibility to be used as a primary tool in detecting cancers. Conclusion: FNAC is a fast, reliable, and efficient method for diagnosing malignant lymphadenopathy. The cytological diagnosis can sometimes be accepted as the definitive diagnosis without further correlation with histopathology, especially in advanced malignancies and known primary malignancies.