The authors present a series of 140 patients who underwent surgical biopsy guided by an isolated anomaly on mammography without any clinical sign. 27 cases presented an opacity with a long axis less than 10 mm, 59 cases presented isolated areas of micro-calcification and 54 cases presented images of focal distorsion of the glandular architecture. By means of pre- and intra-operative radiographic guidance, the histological analysis of serial sections of these abnormalities was possible in every case, resulting in the diagnosis of 54 cases of benign dysplasia, 31 transitional lesion, including 16 in situ carcinomas and 55 carcinomas, including 34 invasive cancers. The advantage and limitations of this diagnostic approach are analysed. The discovery of a large number of sub-clinical carcinomas, the favourable implications for preservation of the breast and the survival justify the indications for surgical biopsy on the discovery of an isolated mammographic abnormality.