Encyclopedia of Cancer

Living Edition
| Editors: Manfred Schwab

Lobular Involution of the Breast

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27841-9_3403-2



Involution refers to a progressive decrease in the size of an organ usually associated with a decline in function. Organs that undergo involution include the postpartum uterus, the ovaries after menopause, the thymus gland, and the milk-producing lobular structures of the breast. Except for the postpartum uterus, involutional changes are regarded as a manifestation of aging and are often irreversible.


Anatomy of the Human Breast

Although variable, the adult human female breast, in general, consists of 15–20 irregular lobes that are separated by layers of connective tissue as they fan out from the nipple into the mammary gland proper. These lobes empty independently into the nipple through the lactiferous ducts, which conduct milk to the nipple. The lactiferous ducts subdivide and terminate in multiple small lobules, which subdivide into multiple glandular acini or alveoli that produce milk during lactation. These lobules...


Breast Cancer Breast Cancer Risk Mammographic Density Breast Cancer Risk Factor Reduce Breast Cancer Risk 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.



The views expressed are those by the authors and do not necessarily reflect the official views of the Uniformed Services University of the Health Sciences, the Department of Defense, or the US Government.


  1. Cowan DF, Herbert TA (1989) Involution of the breast in women aged 50 to 104 years: a histopathological study of 102 cases. Surg Pathol 2:323–333Google Scholar
  2. Henson DE, Tarone RE (1994) Involution and the etiology of breast cancer. Cancer 74(Suppl 1):424–429CrossRefPubMedGoogle Scholar
  3. Hutson SW, Cowen PN, Bird CC (1985) Morphometric studies of age related changes in normal human breast and their significance for evolution of mammary cancer. J Clin Pathol 38:281–287PubMedCentralCrossRefPubMedGoogle Scholar
  4. Khodr ZG, Sherman ME, Pfeiffer RM, Gierach GL et al (2014) Circulating sex hormones and terminal duct lobular unit involution of the normal breast. Cancer Epidemiol Biomarkers Prev 23(12):2765–2773CrossRefPubMedGoogle Scholar
  5. Milanese TR, Hartmann LC, Sellers TA, Frost MH, Vierkant RA, Maloney SD, Pankratz VS, Degnim AC, Vachon CM, Reynolds CA, Thompson RA, Melton LJ 3rd, Goode EL, Visscher DW (2006) Age-related lobular involution and risk of breast cancer. J Natl Cancer Inst 98(22):1600–1607CrossRefPubMedGoogle Scholar

Authors and Affiliations

  1. 1.Uniformed Services University of the Health SciencesBethesdaUSA
  2. 2.Department of Epidemiology and BiostatisticsThe George Washington University School of Public Health and Health ServicesWashingtonUSA