Pathology and Pathological Disorders

Breast Pathology

Breast cancers can be divided into two main overarching groups: the carcinomas and the sarcomas. Carcinomas are cancers that arise from the epithelial component of the breast. The epithelial component consists of the cells that line the lobules and terminal ducts; under normal conditions, these epithelial cells are responsible for making milk. Carcinomas comprise the vast majority of all breast cancers and will be further discussed below. Sarcomas are rare cancers that arise from the stromal (connective tissue) components of the breast. These stromal component cells include myofibroblasts and blood vessel cells, and cancers arising from these "supportive" cells include phyllodes tumors and angiosarcoma. Sarcomas account for less than 1% of primary breast cancers.