Breast cancer is the most frequent cancer in women and the leading cause of death in women under 50 years in the USA. In Italy, the Pool Airtum 2007-2010 figures confirm that breast cancer, excluding skin cancers, is 29% of cancers diagnosed in women and the leading cause of death in women, for the regions in which are active the cancer registries . Among women, breast cancer ranks first in all age groups: represents 29% of deaths in women aged \<49 years, 23% in women between 50 and 69 years and 16% between women aged\> 70 years. The disease is uncommon before age 30 but the European Cancer registries have detected since 1990 an increased incidence of breast cancer in women before age 40. For this reason it can be important to start to verify the incidence of breast cancer before age 40 in the BREAST UNIT of the Tuscany North-West Wide Area (Versilia, Lucca and Massa-Carrara). Mammography, which is the reference examination for prevention in women after age 40, has not shown before this age evidence of efficacy. Ultrasound examination, complementary to mammography, is generally well tolerated but did not demonstrate efficacy in prospective studies as a screening in reducing mortality. MRI with intravenous contrast medium is considered the exam with higher sensitivity in identifying neoplastic lesions especially in young women. This study therefore aims to review retrospectively cases of breast cancer of the centers belonging to the BREST UNIT Tuscany North-West Wide Area to locate a number of cases to allow for a comparison on the imaging characteristics (ultrasound, mammography and mammary MRI if available) of breast cancer and assess whether in women \<40 years the typical imaging presentation pattern of malignancies observed in women\> 40 years are confirmed. In this study will be involved pathological anatomy of the BREAST UNIT Tuscany North-West Wide Area (Massa-Carrara, Versilia, Lucca); Radiology (Massa-Carrara, Versilia, Lucca); Clinical breast surgery / oncology / radiology of the three USL (Massa-Carrara, Versilia, Lucca) of the Tuscany North-West Wide Area. Data of patients diagnosed with breast cancer from 01/01/2009 to 31/12/2015 will be collected starting in july 2016 and the publication of results will take place by December 2016.Risk factors, genetic mutations, receptors status, tumor stage, therapies for NHL / LH and previous breast tumors will be analyzed as well. The data will be stratified by: age (\<30 years, 30-35 years and 35-39 years), biological parameters on histology, stage at diagnosis and imaging features. Patients undergoing breast biopsy sampling represent an already select group who may be susceptible to information bias inherent risk factors: to reduce this bias will recover all the information about the risk factors for breast cancer. 2) operator-dependent variability of ultrasound images: will be taken into account in the data analysis, as well as different machines used in the various hospitals and diversity of the reporting method. 3) The patients for which it will not be possible to correct analysis of the data will be excluded, but the selection bias of patients will still be taken into account in the analysis of the data.The statistical analysis will be done in 1 month, and the results will be published by December 2016.