Is it possible to have BPD and AVPD?

...

Borderline?

Yes, it's possible. I was diagnosed Borderline with features of AVPD. A lot of the symptoms can overlap. You should look into the subtypes of BPD. There is one called Discouraged Borderline that mimics aspects of AVPD. I don't relate as much to the lashing out at other people. I'm moreso passive-aggressive and self-destructive.

If it isn't possible, then my psychiatrists lied to me; I have both Borderline PD and AvPD.

Yep, some paragraphs in Millon's description of how BPDs deal with fear of rejection could be placed word for word into the AvPD description. I can easily see dual diagnosis, and many on this board have it.

Millon also postulates that most borderlines have a "primary" PD that failed to stabilize and decompensated into BPD. For some HPD, for example, and for some AvPD is easily conceivable. (Something for those avies who can't get it under control and think they will get worse to look forward to, huh?)

I think this is certainly possible; I was only diagnosed (half a year ago) with Avoidant Personality Disorder, although there was also Bipolar II (Rapid-Cycling), which nowadays I believe seems to be more like Borderline Personality Disorder instead.

This was something I've been wondering about for a long time, actually, thinking I have both.

The girl I ran into recently definitely had BPD with avoidant features. She was more avoidant than me and I'm supposed to be the avoidant.