Even if a breast cancer is detected in an early phase, 25 to 30% of the patients will develop distant metastases.Identification of cancers with poor prognosis could determine which patients will most benefit from systemic therapy.The presence of a fibrotic focus (FF) is an independent prognostic factor and preoperative detection could be important especially for patients planned for neo-adjuvant therapy.In a study of 268 enhancing malignant masses, we correlated the enhancement pattern (homogeneous, non homogeneous,the presence of a less or later enhancing centre) with histopathological examination.A later or less enhancing centre in a carcinoma presenting as an enhancing mass on magnetic resonance (MR) mammography, corresponded in our study with a fibrotic focus in 64,6%.