Are all these conditions linked?

I have a number of skin problems all having to do with cysts.  I get sebaceous cysts on my scalp.  I have keratosis pilaris on my arms, thighs, and sometimes cheeks.  I have a cyst in my tongue that the doctor says is like a clogged skin cyst, just on my tongue.  I have never had a problem with acne whatsoever, except I used to get deep blackheads on my back when I was a teenager, that the dermatologist had to take care of in her office.  My question is--are all these conditions related?  I take evening primrose oil  and eat Smart Balance so I get omega-3's in my diet.  Is there some sort of underlying condition that would cause all these cysts?  I do have PCOS, but I know that it is probably not related to these other conditions.  It just seems like a lot of cysts!  I also have a cyst on my breast that does not show on ultrasound and the doctor cannot seem to get any fluid out of it when he puts a needle in it.  He thinks it is a sebaceous cyst or scar tissue from the cyst that was there.  

If these are all related somehow, it seems there would be something I could do to prevent some of this from happening.  The only thing I have been able to alleviate is my keratosis pilaris on my arms, by applying 100% pure shea butter twice a day.  Any information you can provide would be helpful.  Even if it is just personal experience, or if there is someone else out there like me.