Pcos but no cysts. What does this mean?

I have all of the symptoms of pcos and hormonal levels but when I had an ultrasound when I was 16 they couldn't find cysts. What does this mean? Might this just mean I had been on the pill so long (since14) and barely had any periods before then that none actually had chance to develop? I am 28 now and was on the pill without a break from 16 until April last year. Without the pill am I likely to develop cysts?
Thanks x
Thanks x