Diseases of the human breast: selective isolation and exposure of epithelia and their correlative surface features and histopathology.

Tissues from seventy-one patients were obtained within one-half hour of biopsy, mastectomy, or reduction mammoplasty and processed for scanning electron microscopy (SEM). Epithelial structures were detected by supravital staining with methylene blue and isolated by microdissection. Mammary lobules and ductules required bacterial collagenase digestion to remove the covering stroma for optimal visualization. Major histopathological categories were compared and correlated with the characteristics observed with methylene blue supravital staining and light microscopy and/or transmission electron microscopy as a function of surface features revealed by SEM. Mammary ducts can be readily distinguished from ductules and lobules by their characteristic surface epithelium. Duct epithelium undergoes a variety of changes in fibrocystic disease (FCD) and in carcinoma. Both apocrine and merocrine secretory activity was observed in the surface epithelium. Proliferation of both epithelial and stromal elements was observed in benign fibroadenomata. Intraductal carcinomas were distinguished by their relative lack of surface microvilli. SEM offers a practical tool in the potential identification of premalignant cells of the human breast epithelium.