The significance of nipple to lesion distance variability on mammography

Nipple to lesion distance (NLD) was measured on at least two mammographic views of 17 malignant and 16 benign lesions. The difference between the maximum and minimal NLDs (maximum difference) was calculated for each. The mean maximum difference was 3.8 mm for the malignant lesions and 10.8 mm for the benign lesions (P less than 0.0001). A maximum difference in NLD of greater than 10 mm implies free mobility of a lesion and is strongly suggestive of a benign process. This new mammographic sign can be used as an additional factor in deciding whether open biopsy is necessary when needle biopsy has failed to provide a definitive diagnosis.