You really shouldn't since it's extract and it was boiled at the maltser, so any dms precursors SHOULD be boiled off already. BUT if you want to be sure factor in a 90 minute boil, like we do with AG. But it should be gone. It won't hurt anything.
Never had a problem at all with Pilsen DME. I've used it in several batches so far and all came out great. I think the whole Pilsen DME thing is a total myth.