Recently I received a question from a CaseInterview.com student who was interviewing with BCG in Africa for an associate position. His question was should he focus his case interview preparation on studying for specific types of cases based on the location of the firm he was interviewing with (i.e. since he was interviewing in Africa he asked if he should specifically focus on new market entries, growth strategies since this would be the issues most prevalent to businesses based in Africa).
My answer is It's very hard to predict what type of case you will get. Some firms and some offices will standardize the cases given so it's random. In some offices, the case is determined by each individual interviewer, and they will tend to give cases based on their own client work -- so the cases will skew towards whatever type of work that office does (where the interviewer works, which may differ from the office you want to work in).
In terms of what to focus on in preparing, I wouldn't over think and try to guess the case type. Practice a range of cases and work on sharpening the underlying SKILLS that allow you to handle any type of case or industry.