My healthy, 4 year old son was born with about a 2 inch birthmark down his neck. I was told it was an epidermal nevus and not to worry. After 4 years and just a little bit of changing (mostly the texture and growing as he grows) I decided to take him to a dermatologist just to be safe. It was biopsied, and I was just told it is consistent with a LINEAR epidermal nevus and that it is fine. My worry now comes from the little bit of information that I also received from the dermatologist, informing me of possible complications that could come up in the future regarding eye, muscle, and neurological issues... I guess called L.E.N. syndrome. What I'm wondering, is if something was going to go wrong, wouldn't things be showing up by now after 4 years? My son is very healthy and developing right on track. Can this now change in the future and he develop something after this long? He only has the one mark on his neck and no other conditions of any kind. Thanks for any information you can give!