Background: Lymphomas are malignant neoplasms of the hematopoietic system, broadly categorized into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Accurate diagnosis requires the integration of cytology, histopathology, and immunohistochemistry (IHC), which helps determine lineage, classify subtypes, and guide therapeutic decisions. Objectives: To correlate cytological and histopathological diagnosis of lymphomas, differentiate B-cell and T-cell lymphomas using IHC markers, and emphasize the importance of histopathology and IHC in classification, therapeutic, and prognostic evaluation. Material and Methods: This descriptive study, conducted at K.A.P.V. Government Medical College, Trichy, included 40 surgically resected lymph node specimens over 4.5 years (January 2018–June 2022). All cases underwent cytology, histopathology with H&E and Giemsa stains, and IHC using CD3, CD15, CD20, CD30, BCL6, CD99, and others. Cytology findings were compared with histopathology and IHC to evaluate sensitivity, specificity, and diagnostic accuracy. Results: The study included 22 males and 18 females, mean age 52.1 ± 20.1 years. Cervical nodes were the most common site (52.5%). Cytology diagnosed 35% HL, 27.5% NHL, and 20% lymphoproliferative disorders. On histopathology, 42.5% were HL and 57.5% NHL. IHC showed HL cases positive for CD15 and CD30 (94.1%), with CD20 positivity in 76.4%. All NHL cases expressed CD20, with additional positivity for CD3 (78.2%), BCL2 (26%), BCL6 (13%), and CD99 (4.3%). Final diagnosis revealed mixed cellularity and lymphocyte-rich HL subtypes, while NHL included diffuse large B-cell lymphoma (26%), follicular lymphoma (22%), and peripheral T-cell lymphoma (17%). Cytology showed 100% specificity but lower sensitivity, particularly for NHL (72%), with diagnostic accuracy of 92.5% for HL and 86.5% for NHL. Conclusion: Cytology is useful as an initial screening tool but limited in sensitivity and subtyping of lymphomas. Histopathology remains the gold standard, while IHC significantly enhances accuracy by confirming lineage and refining classification. An integrated approach combining cytology, histology, and IHC is essential for precise diagnosis, prognosis, and optimal treatment planning.

Lymphoma, Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, Cytology, Histopathology, Immunohistochemistry (IHC).