What happens if your breast ultrasound comes back abnormal?

Breast Ultrasound: That depends on what the ultrasound abnormality is. Typically a breast sonogram is performed to add information to abnormal mammogram findings in order to help the radiologist determine whether the findings are attributed to a BENIGN process (come back in 1 year), PROBABLY BENIGN (come back in 6 months) or SUSPICIOUS (biopsy).

It depends: on the level of suspicion of the abnormality, which is based on various imaging features and(usually) correlation with mammography. If the abnormality is deemed "probably benign"(BIRADS 3, less than 2% chance of malignancy), the usual management is 6 month follow up. If it is suspicious(BIRADS 4 or 5), biopsy would be indicated.