Bilateral primary diffuse large B-cell lymphoma of the breast: diagnostic and surgical management-a case report.

Background: Primary breast lymphoma (PBL) is a rare extranodal lymphoma of which diagnosis is challenging due to overlapping clinical and imaging features with breast carcinoma. While the existence of PBL is known, the diagnostic significance of specific sonographic patterns like the "grid-like echo" and the critical imperative for exhaustive systemic staging to differentiate primary from systemic lymphoma warrant emphasis. This case is unique as it demonstrates a diagnostic journey from a bilateral "grid-like echo" on ultrasound to a revised diagnosis of a systemic, high-grade lymphoma, highlighting key pitfalls and the necessity of comprehensive workup. Case Description: A 38-year-old female presented with systemic symptoms. Bilateral breast ultrasound revealed Breast Imaging-Reporting and Data System (BI-RADS) 4 lesions with a distinctive "grid-like echo" pattern, well-defined hypoechoic masses, and rich vascularity. Core needle biopsy confirmed a high-grade B-cell lymphoma. However, comprehensive staging-including bone marrow biopsy, cytogenetics, and positron emission tomography-computed tomography (PET-CT)-revealed widespread disease, a t(8;14) translocation, Conclusions: While ultrasonography holds significant value in detecting and suggesting PBL, definitive diagnosis depends entirely on pathological evidence acquired through surgical biopsy. The cornerstone of treatment is systemic chemotherapy, and radical surgical resection does not improve patient survival. Therefore, the indispensable role of surgery lies in its diagnostic, not therapeutic, capacity. Enhancing awareness of PBL and establishing a multidisciplinary diagnostic model that integrates surgery, ultrasonography, pathology, and clinical practice is essential to avoid misdiagnosis and develop individualized treatment strategies.