RESUMEN
INTRODUCTION: Primary breast lymphoma is a rare form of localized extranodal lymphoma, which affects the mammary glands unilaterally or bilaterally, and can also affect the regional lymph nodes. MATERIALS AND METHODS: We reviewed 55 patients, with disease stages IE and IIE, diagnosed in 16 Spanish institutions between 1989 and 2016. A serial of clinical variables and treatment were collected, and overall survival (OS) and progression-free survival (PFS) were calculated. RESULTS: Of the 55 patients, 96.4% were women with an average age of 69 years. A total of 53 patients corresponded to non-Hodgkin lymphoma (NHL), of whom 36.3% had lymph node involvement upon diagnosis. Of the patients, 58.2% were stage IE, and 41.8% were stage IIE. Treatments received included radiotherapy (36.3%), chemotherapy (85.5%), and rituximab (in 38 of the 45 patients with NHL treated with chemotherapy). In all, 82.2% of complete responses were achieved. OS and progression-free survival at 5 years in NHL patients was 76% and 73%, respectively. CONCLUSION: Current treatments (chemotherapy, immunotherapy, and radiotherapy) achieve good control of the disease, with an OS of 5 years in 80% of the patients, although there is no consensus in treatment, given the scarce incidence of these lymphomas.