Pathogenesis of breast carcinoma

Breast cancer usually develops after a series of epithelial changes in the terminal ductolobular unit. There are multiple benign causes of breast lumps, the majority of which are not associated with an increased risk of breast cancer. Histological changes of pre-malignancy such as atypical hyperplasia and in situ carcinoma can be identified, and these are indications for either close surveillance or further surgery. At the time of diagnosis, breast cancers can be staged both clinically and pathologically, and this facilitates international comparisons of results of treatment.