Elastosis and other stromal reactions in benign and malignant breast tissue: an ultrastructural study.

The stroma and stromal reaction in normal breast, benign, and malignant breast tissue was studied by electron microscopy. Elastosis is the main stromal response in infiltrating duct and lobular carcinomas. Medullary carcinoma elicits no significant elastosis but intraductal carcinoma has significant local elastosis. Benign conditions such as fibroadenoma and sclerosing adenosis produced no significant elastosis. The high number of elastic fibers and the high microfibril:elastin ratio indicate that most of the elastic fibers are recently secreted, probably by fibroblasts and myofibroblasts. The factors stimulating the increased production of elastic fibers and the prognostic significance of elastosis remain unclear.