http://www.prplastic.com/new_page_382.htm
"Sometimes the breasts do not develop properly and you end up
having nipples that are inverted or have caved into the breast.
This condition affects some women, who of course would rather not
have it.
The nipples tend to retract or invert. The nipples can form a slit
or depression when retracted. Such problems come in different
degrees of nipple inversion. In the milder forms, manual
manipulation can make the nipple come out. In the more severe
forms, the nipple cannot be everted.
For many women, having inverted nipples can be distressing. Nipples
lying flat against the breast or actually pulling in from the
breast surface can be a source of self-consciousness and
breastfeeding problems.
Inversion of the nipple is caused by a short milk duct system
running from the chest wall to the nipple.
Women with inverted nipples basically have a choice of two types of
surgical treatments - surgical (with small scars) or surgical (with
no scars).
Dr. Speron has been resculpting nipples for many years. "