It's useful and it's not going to hurt and could certainly help get a path residency spot, but it's likely to be a hard year. If you go that route, be ready to explain that your interest was always pathology (if that's true) but you wanted to fill in that gap year with something.
A few pathologists started as surgeons, or really think one should have a physician/surgeon background in order to be a better pathologist -- my first 'chairman' (technically he was the private group's President; the private group contracted to run the residency though there was a separate academic department and chair) was such but retired very "successful" as a pathologist. He also recognized the benefit of talking the same language as surgeons/understanding their issues, and the importance of marketing to them to be successful. Some don't think that way. And of course, a prelim/intern year alone only learns you so much, though it will be more than you knew before. But as long as the programs you apply to in pathology don't think you're just a schmuck who can't figure out what you want to do and decided -after- starting a surg prelim year that it was too hard and you wanted something easy and everyone says path is easy..then I think it would be a perk.
