[Histology of precancerous lesions of the breast].

The authors are dealing with the problem of pre-cancerous lesions from data contained in the pathological archives of the Institut Gustave-Roussy. One series consists of 320 cases operated upon for benign lesions or tumors of the breast (Fibroadenomas appearing at a relatively advanced age) of which 4 developed cancers. The past histories of another series of 730 patients having had mastectomies for cancer are examined; 24 of these had been operated upon previously for benign tumours or lesions of the breast. Attention is drawn to a number of histological signs the presence of which in an "a priori" benign lesion should evoke caution: multilayered epithelium of the galactophores glands with an "en flammèche" appearance, tubular adenomatous hyperplasia, irregular lobular hyperplasia, microcalcifications... Despite careful examination of multiple sections, the pathologists decision between benign and malignant lesion continue to be difficult.