We had to take Drew to the Dermatologist yesterday to have the scar checked out. Come to find out it is a birth defect and genetic. We can't think of anyone that we have ever seen a scar like that on either side of our family, so we are stumped.
It is called Aplasia Cutis Congenita
http://www.dermnetnz.org/lesions/aplasia-cutis.html from the pictures I have seen on the internet, it could have been a lot worse. Basically it is a scar that will never grow hair and will continue to get larger as his head gets bigger: Aplasia Cutis Congenita is a rare disorder with a complicated pattern of inheritance. Babies are born with the absence of certain layer(s) of skin, most often on the scalp, but also on the trunk, and/or arms and legs. The affected area is typically covered with a thin, transparent membrane. The skull and/or underlying areas may be visible and be abnormally developed. Aplasia Cutis Congenita may be the primary disorder or it may occur in association with other underlying disorders.
So I am pretty freaked out about it. The doc said that it is just the skin and there didn't appear to be any skull abnormalities by touch, but if the scar ever bubbles up like a mushroom he will have to cut part of it out and do a biopsy. I'm sick to my stomach thinking about it!!