I'm a PGY-II in pathology and have had several conversations with the AOA about this. As it has been explained to me, pathologists don't have to do the TRI year. The first-year curriculum standards are basically very lenient for pathology because there is no DO pathology residency available. You will apply for approval under resolution 42, which includes:
1) Membership in good standing of the AOA
2) An application
3) A letter from the ACGME program where the PGY-1 year was completed, including training dates and the completed rotations. (This is what is usually compared to the osteopathic curriculum but is pretty much approved regardless for pathology because of the lack of a DO alternative. See
http://www.osteopathic.org/inside-a...riculum-for-approved-ogme-1-training-year.pdf)
4) Provide proof of an osteopathic educational activity. This can include attending an AOA-sponsored conference where you can earn at least 8 category 1A CME hours, presenting an osteopathic clinical presentation to the current ACGME program, or attending osteopathic training modules through a regional Osteopathic Postdoctoral Training Institution or AOA-approved residency-training program. I'm planning to do the conference/8 CME hours option.
You have to wait until your first year of residency is complete before you can apply, and that's pretty much it. No need for a TRI, just some paperwork and a few hoops to jump through, and you're good to go.
Hope this helps!