What is this mark on my leg?

[ifancyachinese]

Just noticed it as I got out of the shower. Looks like a mole where it's darker in middle, lighter at edge but I don't think it is a mole. It's flat to the skin, doesn't hurt, perfect circle and very light brown.

Any ideas?

If you've just noticed it then see how it goes over the next few weeks.
It's good you've taken a photo as you can see if it's changed.