Introduction: The optimal management of breast lesions with atypia (BLA), detected in percutaneous biopsies after screening mammograms, is a controversial issue. The aim of this paper is to compare histological diagnosis by percutaneous biopsy with the results of the surgical biopsy of these lesions and to analyse the changes to clinical approach this would imply.

Method: A retrospective study was carried out on patients operated on between June 2007 and June 2017 with a diagnosis of BLA. One hundred and forty-seven patients were identified with a pre-operative diagnosis of flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), atypical lobular hyperplasia, lobular carcinoma in situ and other atypia.

Results: The average age at diagnosis of BLAs was 52 ± 9.4 years. Radiologically, the lesions presented as microcalcifications in 79%, nodules in 15.6% and other lesions 5.4%. 73.5% of these were biopsied by means of digital stereotaxis. All of the patients analysed underwent a partial mastectomy. Changes in a biologically high-risk lesion were observed in 26.5% of the surgical specimens, of which 75.5% corresponded with ADH and FEA. In the percutaneous biopsies consistent with ADH (40.1%), ductal carcinoma was discovered in 6.8% (5.1% in situ and 1.7% invasive), which implied specific, multi-disciplinary management. Of the FEAs, 84.8% required a second treatment (surgery and/or hormone therapy ± radiotherapy, depending on whether it concerned FEA 59.6%, ADH 21.2% or ductal carcinoma in situ 3.8%).

Conclusion: These data show the clinical relevance in the diagnosis of ADH and FEA in percutaneous biopsies. For the diagnosis of FEA in particular, the associated risk of biologically high-risk lesions and ductal carcinoma is made evident.