Depends on how far you want to take it. It doesn't appear to me that, strictly speaking, you should be able to count those cases towards your 2000 minimum total -- even if that's weakly debateable by the letter of the pathology standards, I can't see how it fits the spirit of ACGME's intent.
Separate and apart from that is the financial issue. This individual is most likely getting paid an academic salary/supplement or at least that practice is getting additional income for teaching. If they're failing to live up to those obligations then their problem is a lot bigger.
Unfortunately you're in a crap position because if you yell loud enough and long enough to someone who can do something about it, you risk things like the program closing/being closed, or being saddled with woefully disgruntled faculty. If the former, you're actually in a good position to transfer -- as good as any, anyway. The latter is considerably less pleasant. There's also the possibility that the problem will be properly fixed and everyone can move on without things becoming terribly radical.
Personally, my level of tolerance for that kind of thing, if it's as you describe and I envision, is quite low, and I'd start documenting your complaints (calls, letters, emails, meetings, summarize what you said and were told, & date) and their results (every time you asked and did or did not get attending sign-out, etc.), and work your way up the ladder from PD, AP director, department chair, etc. until you're talking to a dean/local GME or the ACGME, or something improves. Ideally you would be able to get some more residents willing to walk the walk with you. Having been through something similar but in an undergrad program, documentation and having some other people on board saying the same thing is very important when you start considering basically badmouthing faculty to their superiors.
I'm not a big fan of the passive-aggressive approach of taking all their cases afterwards and going around to every other attending in the department and asking something about each and every dadgum one while mumbling about how X wouldn't look at them with you. But it happens, and is a probably effective if slimy way of manipulating the situation.
In general, these kinds of problems tend to go away with a few meetings & chit-chats with the right people in a professional way, and a little flexibility in setting up times to work with the attending, without all of the ornery stuff which has the potential to get unpleasant. But if multiple complaints to the PD and honest attempts to work things out with the attending continue to be met with active avoidance of teaching, then I'd get more serious. They're not doing you a favor by signing out with you -- it's their job.
If you feel like you really, really don't want to risk pushing the envelope, then I agree with previewing, writing your thoughts (don't just think them, actually make the commitment and write them somewhere -- in pathology, phrasing matters as much as being "generally" correct), and post-viewing with the final signed-out report. Take the ones where you're wrong and aren't sure why and either go to the sign-out attending and ask just about those ones, or if he still refuses then take them to your PD/AP director and ask for some teaching -- I don't see a problem with that. And of course make all the more of your other opportunities to sign-out with a teaching pathologist.
