I would strongly disagree with the above statement.
I would study ALL fields, because every year there is something that is WAY over-represented, and if that's the thing you skipped you are f*cked.
When I studied for the boards, I was told that it was GU (really prostate) and breast heavy. I studied the crap out of those 2 fields. Guess what? I had a total of 3 prostate and breast questions each. I really didn't study derm or neuro because I was told there were only a handful of questions each. You know what happened- a TON of BOTH. I basically "skipped" neuro- bad mistake, and the derm lesions were not straight forward either.
However, I would say that derm, hemepath, and neuro are the easiest fields to prepare for on the boards, since you pretty much know what they are going to ask:
Derm:
1. Melanoma. Expect a lot of "is this melanoma or something that looks like melanoma?" So study Spitz, cellular blue nevus, dysplastic nevus, etc. These are heavily represented on slides.
2. Inflammatory. There will be questions on bullous diseases (they love these for some reason), and lupus. I would completely ignore the rest of inflammatory derm. It's too hard and subtle for you to make a reasonable diagnosis in the short time you have.
3. other derm neoplasms. know all the major ones. This is where it can get unpredictable.
Neuro:
1. Neoplasms. Duh. know the major types. These won't be tricky, unless you've never seen them before. There really aren't that many (maybe 10 or so) so this is pretty easy, IMHO.
2. inflammatory- you can probably skip this. Not reasonable for you to know this in depth without a fellowship.
3. They love gross brains for some reason.
Heme:
1. MAJOR lymphoma types. Like 6 or so, on histology alone. There's so many weird classifications now based on flow, etc., well you won'y get flow on the AP exam since that's a CP topic.
2. benign conditions that can mimic lymphoma in lymph nodes. These get tested pretty heavily for some reason.
3. That's it. Maybe 25-30 entities TOTAL worth studying.