I'm pretty sure i have a patch of A.N. on my back. It's always been there, but fades and then gets darker. It looks like someone threw a handful of sand at me and it stuck. It almost totally disappeared at the end of my pregnancy and for my first few post-partum months. I'm not sure if that's what it really is, or if it's something else, but i read a description of A.N the other day and i think it probably is.