I too have recently discovered weird creases developing in my skull. First was the back of the head, by the neck running side to side, in March. I talked to my doctor in June and we did an MRI. Nothing showed up. She assumed it's a fatty tumor, which wouldn't show up on an MRI. I've been monitoring it. Seems like it's stretching out more. Last week I felt this tickle on top, like a big was in my hair. This went on for 2 days. Today I notice another crease and bump on the top of my head. About 3 fingers long. Anyone have any answers? My MRI didn't show anything. Gp didn't seem concerned.