I very very rarely hear "in this case" (except by foreigners - it seems a common mistake). The only exception to this that I know of is when you can actually point to the case. That's an odd thing to say, but imagine a business meeting: your company has just performed some kind of action that will elicit a response from someone else, and the response might be one of three things. You write them up on the flipchart, and point to the first thing they might do, and say "so, in this case, we will...". The odd thing about this is, though, if you were having the same meeting without the flipchart and couldn't point to it, you'd probably say "so, in that case, we will...".
(This feels to be very dialect-specific to me, so don't assume this is true for everyone - this is just what makes sense in my head as a British English speaker.)