I want to install an inset medicine chest. A 2" pvc pipe is in the way. If this is the vent pipe can I simple add elbows and bend around the chest?

Yes but you must be sure this is not a wet vent. If it's a dry vent you can cut it and add your elbows making sure your horizontals perefctly horizontal or slightly kick in the direction that any water getting inside will fall towards to down side.