Weird russet potato?
I would guess it might just have leaned against a stone as it grew, the texture difference would be from the skin reacting to something pressing on it if so.  Or it might be a scar that's healed over.  I've seen lots of garden-grown potatoes with imperfections, they're usually not a problem.

It is probably safe to eat if there's no interior discoloration or other signs of trouble.  If you're really unsure, you can peel the potato, or just slice the peel off in that area.