Supernumerary Breast Tissue: Historical Perspectives and Clinical Features

, Department of Pathology and Laboratory Medicine, Emory University School of Medicine.

South Med J. 2000;93(1) 

In This Article

Abstract and Introduction


The presence of extra nipples and breasts, polythelia and polymastia respectively, is not uncommon. Such supernumerary breast tissue usually is found within the milk line extending from the axilla to pubic region. It was once thought that this condition was a symbol of increased fertility and femininity. Anne Boleyn was said to have a third breast. Ancient goddesses of fertility had row upon row of breasts on their chests. Polythelia is seen congenitally. Ectopic breast tissue and polymastia may not appear until enhanced by sex hormones during puberty or early pregnancy. The same pathology that can affect normally positioned breasts, including carcinoma, can occur in supernumerary breast tissue. Renal and other organ system anomalies are associated with supernumerary breast tissue. Further research is needed to establish the clinical significance of supernumerary breast tissue in light of its reported associated conditions. Appropriate treatment is yet to be refined.


Polymastia (supernumerary breasts) and polythelia (supernumerary nipples) are extras in sites unexpected. These anomalies appear more so in women than men. The full spectrum of extra parts -- from nipples to fully formed breasts -- is wide-ranging. Polymastia may be seen as a normally shaped female breast with a nipple and areola. In attenuated forms it may be breast tissue with nipple lacking areola, glandular tissue with areola but without nipple, or only ectopic breast tissue with neither areola nor nipple.[1] Supernumerary nipples are often miniature compared to normally placed nipples. The occurrence of extra breasts and nipples varies, but it generally is in the range of 1% to 2% of the general population[2,3,4] and is reported to be as high as 6%.[5]

The genesis of extra breasts lies in hidden, quiescent primordial breast tissue along "Hughes lines," also known as mammary lines or simply "milk lines."[6] In the fourth to fifth weeks of normal embryonic development, two surface thickenings occur along the sides of the embryo extending from the axillar y region to the groin. In 2 to 3 months, these thickenings become more pronounced as mammary ridges -- the future site of breasts. Normally most of these ridges (all except two) regress.[6] But as imperceptibly as the germination of a dormant seed in early spring soil, such ectopic quiet breast rudiments can come to life in the right hormonal milieu. When awash in sex hormones at puberty or during pregnancy, such tissue can blossom (Fig 1). And it is not exempt from the physiology and pathology of normally positioned breasts. A common site of ectopic breast tissue is the axilla. Such an occurrence can cause discomfort after childbearing when it lactates in unison with its two sanctioned colleagues.

Figure 1.

Illustration of polymastia and polythelia.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: