thank you for everyone's responses. i took dd to the pediatrician yesterday and they were not much help... the doctor looked at it and brought out the dermatology book... she discussed tubular sclerosis, but said it was rare. it still has me freaked out! http://www.aafp.org/afp/20000201/703.html
it is my biggest concern. but it seems the hypopigented macules called ash leaf spot associated with this usually occur in greater numbers. dd only has the one on her back.
then we talked about nevus depigmentous, i went home and googled it more.
and came accross something else called nevus anemicus...and i am hoping this is most likely what it is since it would mean this is no big deal. just a birthmark.
anyway, they refered me to a pediatric dermatologist at a major hospital about an hour away. i called and made an appointment for her there, but the soonest time she could be see is in two weeks. so i guess we have to wait until then to find out more.
i appreciate all your thoughts and stories about similar birthmarks. and i am hoping it is simply that, a birthmark with no other serious condition associated with it.
it seemed strange to me that my pediatrican had not seen very many white birthmarks. are they that rare? it seemsm quite a few of you have or have children with them...