Histopathological examination revealed features of tuberculous lymphadenitis along with evidence of high-grade NHL, specifically diffuse large B-cell lymphoma (DLBCL) subtype. Immunohistochemistry (IHC) markers were done to confirm the diagnosis, revealing malignant lymphoid cells positive for CD20 (diffuse membranous staining), BCL6 (nuclear positivity in >30% of cells), and MUM1 (post-germinal center phenotype), with a high Ki-67 proliferation index of 80%, consistent with activated B-cell subtype DLBCL. This evidence concerns the gene BCL6 and diffuse large B-cell lymphoma.