I had an IC once armchair diagnose him as borderline narcissistic. I might have tossed that one overboard, if not for the fact that she treated him as an IC for a time as well (she was not treating both of us at the same time).
Additional food for thought to which I occasionally return. I really shy away from this diagnosis because the success rate of any kind of a relationship with a narcissist and/or a cure to the disorder, is near zero. But I have to keep it in the back of my mind.