Ann,
I have seen intraductal papillomas at the base of the nipple, but these bleed
rather than release thickened milk. The danger in persistent plugged ducts is
that they MAY signal a malignancy which is obstructing milk flow. You are
right to be concerned, but there is nothing you can do to force this mother to
seek physician care.
Catherine Watson Genna, IBCLC NYC [log in to unmask]