I know two people that did at least one year of residency in anesthesia in Brooklyn, then did the internship, and then went back. I know one was a USFMG (and, I THINK, did 5th pathway), and I think the other was FMG (although unsure of her citizenship), but neither one had any PGY training before this. The first one did a year of anesthesia, then her intern year in IM, then went back. The second one did 2 years of gas, then intern, then went back to be chief. I asked her if it was weird to be the one called to the floor the week before to tube, then having to stand there the next week, and wait for her colleagues to come and tube a pt on the floor, since the senior IM's wouldn't let the "intern" do it.
Strictly speaking, you could do an advanced residency without an intern year, but you would not be eligible for board certification. However, just like Step I, II, and III, you can do them in any order. Just more logical (and better for your education) to be an intern first.
Also, when I was a student, there was a peds fellow in Endocrine from Argentina; since she had done peds in her country, she came to the US to do her fellowship. However, she liked it so much, after completing her fellowship, she had to do a peds residency again in the US, to stay here. I met her as PL2, and, before we knew about her fellowship, we were amazed at how well she knew diabetes.
