A morphometric analysis of normal and sub-normal human mammary tissue.

A morphometric study of normal and sub-normal adult human mammary tissue is presented. The semi-quantitative analysis showed an increased number of lobules in sub-normal glands versus normal ones. Minor alterations, consistent with the classical concept of incipient fibrocystic disease were found in both. Quantitative morphometry (Multiple Purpose Test) confirmed the first, rather subjective, impression that the section surface occupied by lobules was nearly three times larger in sub-normal glands. This finding was due to an higher number of more extended lobules per surface unit. The extra-lobular ducts in sub-normal tissues appeared larger, but their number per surface unit was not significantly increased when compared to normal specimens. Variations between individuals, even as variations in the same gland were wide. It is suggested that "adenosis" is an age-related phenomenon and that fibrosis and cystic dilatation may be a normal manifestation of ageing of the breast. A reevaluation of the concept of true mammary dysplasia might be needed.