Developing asymmetric breast tissue

PURPOSE: To show that benign asymmetric breast tissue detected mammographic ally may increase over time. MATERIALS AND METHODS: Serial mammograms obtained in 21 women with negative physical examination results and mammographically detected developing asym metric breast tissue were reviewed, and findings were correlated with resul ts of biopsy (n = 16), ultrasonography (US) (n = 8), and contrast material- enhanced magnetic resonance (MR) imaging (n = 3). Five patients who did not undergo biopsy were followed up for 13-84 months. Thirteen of 16 biopsy sp ecimens were reviewed. RESULTS: At the time of mammographic change, 12 patients without baseline a symmetric tissue had a mean age of 41.7 years and a mean size of asymmetric tissue of 2.4 cm. The mean age of nine patients with baseline asymmetric t issue was 46.9 years. In eight patients, the mean size increase was 2.5 cm. One patient showed increased tissue density but stable size. All US and MR images were negative. Pseudoangiomatous stromal hyperplasia was present in all 13 biopsy specimens reviewed and extensive in 12. No malignancies have been reported in five of the followed-up patients, and two have had contin ued enlargement of asymmetric tissue. CONCLUSION: Pseudoangiomatous stromal hyperplasia is a common histopatholog ic finding in developing asymmetric breast tissue. Follow-up, rather than b iopsy, is a management option if benign imaging and clinical criteria are m et.