Where is this shadow coming from?
Solution 1:
There are no future DLCs coming out for Mass Effect 3 - all future Mass Effect content is going to be for the next Mass Effect games (which haven't officially been announced yet).
The shadow looks like either FemShep or Liara (more inclined to go with Liara due to the shape of the head) - since you're not playing FemShep and Liara isn't in the room this shadow is going to be a rendering issue or glitch of some kind.