The “Two Black Dots” on a Child’s Stomach: A Common Concern That Resonates with Many

A while ago, a friend shared a note from Xiaohongshu and asked me if it was reliable.

In the note, a parent asked what two little black spots on the child’s stomach were. Not asking was fine, but as soon as they asked, it immediately sparked tens of thousands of comments. Many people shared their experiences, saying they had grown two, of course, there were also one, three, four, or even more, it was like a big showtime scene.

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As a pediatrician, in clinical practice, I sometimes also observe one or several tissues on the child’s chest wall or abdomen that are similar to the human nipple in appearance, which are usually smaller than the normal nipple. This issue is quite common, so let’s introduce it to everyone below.

What is this phenomenon?

This phenomenon is called accessory breast tissue, referring to breast tissue that exists outside the normal mammary gland tissue and can appear in one or more areas of the body.

Accessory breast tissue is a relatively common congenital developmental anomaly, with an incidence rate of 1%-6%, more common in girls than in boys.
Depending on the tissue it contains, accessory breast tissue can be divided into the following types:

What are the manifestations of accessory breast tissue?

Firstly, accessory breast tissue is usually located along the milk line – the mammary gland development line area that extends from the armpit to the groin (67%), and a few ectopic occurrences are seen on the face, back, thighs, and other parts.

The most common type of accessory breast tissue is the accessory nipple, which looks like a small pink or brown protrusion much smaller than the normal nipple; accessory breast tissue with areola looks like a pink-brown birthmark, and if there is a nipple in the center, it is often a faintly visible small depression; and accessory breast tissue with only glandular tissue is not easy to detect, often found during pregnancy or the puerperal period due to swelling discomfort, leakage of milk.

Why does accessory breast tissue occur? What to do?

During embryonic development, multiple mammary gland tissues can develop along the milk line. The mammary gland tissues outside the normal site will eventually regress, when the regression is incomplete, accessory breast tissue is formed.
Most occurrences of accessory breast tissue are random, and there are also some reports of familial inheritance.

Accessory breast tissue is usually harmless and does not require treatment in most cases.

Some studies suggest that polythelia is associated with renal abnormalities, so the presence of accessory breast tissue may consider completing a renal ultrasound examination to rule out renal abnormalities.

Like normal breasts, accessory breast tissue can also develop inflammation and tumors. If there is hardness in the area around the nipple, significant swelling, pain and discomfort, new lumps or rashes, abnormal discharge, it is necessary to see a breast surgeon in a timely manner.
However, the probability of these occurrences is very small, appropriate attention is sufficient, and there is no need for excessive worry.

If the accessory breast tissue is significantly swollen during the lactation period, the type that can express milk can be relieved by expressing milk, and the type that cannot express milk may consider stopping breastfeeding to relieve symptoms when necessary.
When accessory breast tissue significantly affects aesthetics, elective cosmetic surgery can be considered for removal.