How frequently are false negative results from a biopsy?

Rare but not zero: Pathologic evaluation of breast core biopsy samples has a very low false negative rate. That being said, pathology results need to be reviewed in the context of the imaging and clinical findings. If all three do not match up as concordant, then the possibility of a false negative or sampling error (i.e. missed target) comes into play and repeat sampling/biopsy should be considered.