Primary breast lymphoma is a very rare histological entity of breast cancer. The Clinical and radiological aspects do not present any particular specificities. Diagnosis is often delayed. The treatment is mainly based on chemotherapy. We report the case of a patient with high grade malignant non-Hodgkin lymphoma. The symptomatology was made of breast swelling. The remote extension assessment was negative. The patient received 6 courses of type R mini CHOP chemotherapy followed by three-dimensional radiotherapy with a dose of 30 Gy in 15 fractions for 3 weeks. An echo mammography in between treatment showed: a partial response at 50%. Controle PET CT scan performed 3 weeks after the last cure having objectified: Complete disappearance of the active subcutaneous nodule at the level of the QSE of the right breast. Breast localisation of lymphoma is very rare. His prognosis was considerably improved due to a multidisciplinary approach.