I had a screening mamo and had to go back in for a diagnostic and u/s. the tech just came back and said it looked like simple cyst but to f/u in sept. why f/u for simple cyst? how likely is it to be cancer? i never got a report.i go next week for f/u?

An ultrasound finding of a cystic mass is not generally cause for concern. If the "screening mammogram" was a digital mammogram, and showed no specific areas of clusters of calcifications it is also not concerning. If you have a prime family history (mother, grandmother, first cousin) with a history of breast cancer, consult your physician about further diagnostic testing.