my 10 year old son has developed a "dent" or "dip" on the top, right side towards the back of his head, his skull, doesn't bother him he says unless he's hit in head, it's very noticeable when you touch his head, about as big around as fifty cent piece and as deep (from rest of his skull by feel) as 3-4cm (I'm est.) He had an x-ray & it's clear that his skull indeed "dips" in. His pediatrician said it could be some sort of cancer or other disease, I'm wondering if anyone can please tell me the names of EVERYTHING it could be? He also said it could be a "natural defect". Which means it happened sometime between age 8 & now all on it's own for no reason...that strikes me as hard to believe, am I right, or could this really be a "natural defect"? And if so, will it not cause him problems long term? What kinds of problems, with where it "dips" pushing in on his brain as he grows?