Cyst on placenta

Amaya • 💙Blessed with 4 boys! One angel baby girl who we lost at 15 weeks pregnant 👼
I had my ultrasound today at 19w3d and they found a cyst on my placenta.  Has anyone heard of this or know anyone who had this? 
They will do a follow up ultrasound in 4 weeks to see if it's growing and if so I have to see a high risk doctor :(