Women can have more than two breasts or extra nipple tissue. This condition is known as supernumerary breasts or supernumerary nipples, also medically referred to as polymastia or polythelia. It represents a developmental variation. These extra tissues vary in appearance and may not always be immediately noticeable, sometimes resembling moles or birthmarks.
The Biological Basis of Extra Breasts
Extra breast tissue or nipples develop early in embryonic development. Around the fourth to sixth week of gestation, specialized structures called mammary ridges, also known as milk lines, form on the embryo. These ridges extend from the armpit region down to the groin. Normally, most of this ridge regresses, with only specific chest areas persisting to form the typical two breasts.
If parts of these mammary ridges do not fully disappear, cells can remain and develop into extra breast tissue or nipples. The presence of additional breast tissue with glandular elements is termed polymastia. When only an extra nipple forms, with or without underlying breast tissue, it is called polythelia. This incomplete regression explains the biological origin of these accessory structures.
Appearance and Health Considerations
Supernumerary breasts or nipples vary in form, from a small, mole-like bump or hair patch to a fully developed breast with glandular tissue, an areola, and a nipple. They commonly appear along the embryonic milk line, which runs from the armpit to the groin. However, they can also be found in other areas, including the face, back, or thigh.
These accessory tissues have similar cellular components to normal breasts, responding to hormonal fluctuations. This can lead to swelling, tenderness, or pain, especially during menstrual cycles, pregnancy, or lactation. During pregnancy, supernumerary breast tissue can even produce milk. These extra tissues are susceptible to the same conditions affecting typical breast tissue, including benign growths like cysts and fibroadenomas. Though rare, breast cancer can also develop in supernumerary breast tissue, with reported incidences ranging from 0.2% to 0.6% of all breast cancers.
When to Seek Medical Advice
If you notice any unusual lumps, bumps, or nipple-like structures on your body, especially along the milk line, seek medical advice. A healthcare professional can provide a proper diagnosis, differentiating supernumerary tissue from other skin conditions or lumps. Medical evaluation is important to monitor for any changes in the tissue, such as pain, discomfort, new lumps, hardening, or discharge. These changes could signal a developing issue, including the rare possibility of malignancy.
While supernumerary breast tissue is often harmless and may not require treatment, regular check-ups allow for early detection of any concerns. Removal of supernumerary tissue is an option, sometimes chosen for cosmetic reasons or if symptoms like pain or discomfort arise. If there is a medical concern, such as suspected cancerous changes, surgical removal would be recommended.