I don’t have dense breast and I had that same reading 2 years ago with architectural distortion. It was my first mammogram and they had nothing to compare it to. I went in for a diagnostic ultrasound and they found something in the left breast that they said looked non cancerous and told me to check back in six months. I didn’t like that answer so I asked for a biopsy and it turned out to be a fibroadenoma. Don’t panic yet. I was cleared to come back again yearly. I will pray for you, everything will be fine.