Abstract
Diffuse large B-cell lymphoma (DLBCL) is a rare and aggressive form of non-Hodgkin lymphoma (NHL) that can occur in the breast. This case report details the case of a 48-year-old postmenopausal woman diagnosed with primary breast DLBCL after presenting with a painless, rapidly growing mass. Imaging studies, including ultrasound and mammography, indicated significant breast involvement, confirmed by histopathological analysis revealing large atypical lymphoid cells. The patient underwent the rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy regimen, achieving complete remission after four cycles. This case underscores the importance of considering breast lymphoma in differential diagnoses for breast masses and highlights the effectiveness of timely and appropriate treatment strategies. Ongoing follow-up is essential for monitoring potential recurrences, emphasizing the need for a multidisciplinary approach to managing this condition.