Abstract
Primary breast lymphomas (PBLs) represent less than 1% of all breast malignancies. Intravascular large B-cell lymphoma (ILBCL) is a rare, aggressive form of extranodal lymphoma. Breast involvement has only been described in the literature once previously. ILBCL is characterized by the proliferation of tumour cells within the lumen of small vessels of involved organs, resulting in their eventual occlusion. Clinical features are often vague, diagnosis is difficult and delayed, and prognosis is usually poor. We report the first ever case of synchronous ILBCL and invasive ductal carcinoma (IDC) of the breast in a patient presenting with pyrexia of unknown origin and altered mental status who underwent modified radical mastectomy and subsequent chemotherapy, and review the literature regarding intravascular large B-cell lymphoma, PBLs and synchronous carcinomas and lymphomas of the breast.