[Pathology of premalignant and malignant diseases of the female breast]

There are three frequent, basic diagnoses of breast lesions: fibroadenomas, fibrocystic diseases and carcinomas. The atypical fibroadenoma, the phyllodes tumour, the atypical ductal and/or lobular hyperplasia and the atypical papilloma are important because they may be a premalignant condition. For therapy it is important to know that the non-invasive carcinomas are often plurifocal, multicentric and bilateral. Women with manifest invasive breast cancer have a very high risk of contralateral cancer, but generally the cancer on the opposite side is microfocal.