Kim, there's a lot of disagreement in the scientific research community about whether fibrocystic breast disease carries an increased risk of breast cancer (or if it does, how much); so there are no hard and fast percentage figures available. I'm glad your biopsy was benign; the thing you need to look for with fibrocystic disease is hyperplasia, or atypical hyperplasia, both of which means the cells aren't cancerous yet, but could turn cancerous; ask your doc (or read your pathology report) to see if there was any mention of this, because those two conditions do carry an increased risk for cancer.

As for the ultrasound, shape shouldn't mean anything one way or the other. I'm glad you're taking care of this with an MRI, though. That'll tell you what you need to know. Please try not to worry too much; you're doing the right thing, so just keep moving forward, get the MRI results, and continue to be vigilant (as you have been) about your breast health. Good luck! -PJH