Primary breast lymphoma (PBL) is a rare disease accounting for 0.4-0.5% of all breast malignancies. Diffuse large B-cell lymphoma (DLBCL) is the most common histological diagnosis. The clinical presentation of PBLs is usually no different from that of carcinoma. In this paper we review the literature on the clinical presentation, diagnosis, prognostic factors and treatment options of PBL. In the light of the information gained we discuss three patients with primary breast lymphoma (one with a central nervous system relapse) who were treated in our department in the years 2002-2007. In conclusion: there is no consensus on the question of how to best treat PBL: chemotherapy, radiotherapy or combined therapy. However, the last approach to be the most successful one. Due to high incidence of central nervous system (CNS) involvement in PBL patients, many authors strongly believe that patients with aggressive forms of PBL should receive CNS infiltration prophylaxis, even in the early stages, as this may improve the outcome and significantly reduce the risk of a CNS disease relapse.