RESUMO
Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of non-Hodgkin's lymphoma (NHL). This subtype can be present in various extranodal sites, including the brain, bones, intestines, kidneys, adrenal glands, and other soft tissues. As demonstrated in this case, one rare site of DLBCL is the nasal septum, which presents as a rapidly enlarging mass resistant to antibiotics and steroids. The definitive diagnosis for this case involved biopsy, but further workup, such as computed tomography (CT) and fluorescence in situ hybridization (FISH), helped support the diagnosis of DLBCL. While determining the stage of the lymphoma, treatment with R-CHOP chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) was initiated immediately. This case demonstrates a rare presentation of DLBCL in the nasal septum and describes the significance of urgent examination as well as treatment.