Intravascular large B-cell lymphoma (IVLBCL) is a rare and high-grade disease of neoplastic lymphoid cells within the vascular lumina of small- to medium-sized vessels. The disease carries a grim prognosis despite robust treatment protocols. We discuss the case of a 58-year-old female who presented with mammographic screening abnormality which led to more investigations and ultimately to this diagnosis. The patient had no prior history of a lymphoma or in situ and invasive carcinoma of the breast. To our knowledge, IVLBCL of the breast is a very rare and an unusual location for this type of a lymphoma and so far, only five reported cases. Through our case report, we not only discuss the case but also review literature on this rare entity.