The microenvironment of human breast with clinical cancer.

The characteristics of the mammary glandular tree have been studied in 100 human breasts removed for clinical cancer by radical mastectomy. The glandular tree was observed in whole thin (2 mm) stained sections under a stereoscopic microscope with removal of any suspicious or interesting change for histology. The results allow to categorize as follows the microenvironments in which mammary neoplasia may clinically appear. In respect to the main characteristics of the collateral glandular tree, clinical breast cancer may occur in: (a) atrophic breasts without lobules or lesions in 17% of cases; (b) atrophic breasts with persistent lobules and minor pathologic changes such as cysts, apocrine metaplasia, sclerosing adenosis, fibroadenoma and ductal hyperplasia in 19% of cases; (c) atrophic breasts with proliferative lobular changes (atypical lobules), duct papillomas, in situ carcinomas and/or microscopic independent foci of infiltrating carcinoma in 31% of cases; (d) adenosic breasts, which are breasts rich in mammary lobules, with the minor pathologic changes specified under (b) in 14% of cases; (e) adenosic breasts with the severe proliferative changes specified under (c) in 17% of cases, and (f) adenosic breasts with normal lobules and without lesions in 2% of cases. Therefore, 83% of the cancerous breasts have normal or pathologic lobules and 81% have lesions of various degrees of severity in the glandular tree.