Breast, post-treatment lobular atrophy

There are different histologic changes which may occur in non-neoplastic breast tissue and carcinoma when a patient receives chemotherapy and/or radiation. In this case, the patient had a history of locally advanced left-sided breast cancer on lumpectomy and was also subsequently found to be BRCA1 positive. She chose to undergo bilateral mastectomy following neoadjuvant chemotherapy. The benign breast tissue here shows diffuse lobular atrophy, leading to a decrease in overall lobular size. The number of lobules may also be decreased. Cytologic atypia may be seen in epithelial cells but these changes are not specific. Stromal fibrosis is also evident. This patient was found to have no residual invasive carcinoma.