A supernumerary nipple is an extra nipple that forms before birth. This is a common congenital anomaly. Having an additional one or more is a minor variation in development.
Common Locations
Supernumerary nipples most commonly appear along the “milk line” or mammary ridge. This line extends from the armpit region, down through the chest and abdomen, towards the groin area. About 95% of these extra nipples are found along this path. While they can occur anywhere along this line, common locations include just below existing nipples, on the abdomen, or near the groin. Less commonly, they can appear outside this line, on areas like the neck, back, or feet.
Diverse Appearances
The appearance of a supernumerary nipple can vary significantly, from a barely noticeable pigmented spot to a fully formed nipple with an areola. They are classified by components like nipple, areola, and underlying breast tissue. Some may present as a small, raised bump resembling a mole, often pink or brown and smaller than typical nipples. Other variations include only an areola (the darker skin around a nipple) without a central nipple, or a patch of pigmented skin with some hair. In rarer cases, a supernumerary nipple can include underlying breast glandular tissue, leading to classification as polymastia. The texture of these extra nipples can be bumpy, similar to standard nipples, and may even have a visible dimple.
Distinguishing Features
Differentiating a supernumerary nipple from other common skin lesions like moles, skin tags, or freckles relies on visual cues. Its typical location along the embryonic milk line is a strong indicator, as moles and birthmarks usually do not follow this pattern. Unlike flat moles, a supernumerary nipple often presents as a slightly raised area, potentially featuring rudimentary nipple or areolar tissue. While some supernumerary nipples can resemble moles, they often possess a distinct texture or a central bump. A medical professional can often identify them through a physical examination, sometimes using a dermatoscope for a closer look.
Associated Characteristics
Supernumerary nipples can exhibit characteristics influenced by hormonal changes, similar to primary nipples. During hormonal fluctuations like puberty, menstruation, or pregnancy, they may become more prominent. This can manifest as increased pigmentation, fluctuating swelling, or tenderness. Hair may also grow around a supernumerary nipple. In rare instances, supernumerary nipples containing glandular tissue can even lactate, especially during pregnancy or breastfeeding. Any changes in appearance, discomfort, or discharge should be evaluated by a healthcare provider.