Purpose. To investigate the yield of core biopsy in the histologic characterization of atypical ductal hyperplasia (ADH) and to assess the radiological patterns, if any, of this condition. Material and methods. January 1993 to October 1997 we studied 553 lesions, 8 of them with a diagnosis of ADH made on microhistologic samples obtained with 14G needles. Biopsy was performed under US guidance in 81.7% of cases and under mammographic guidance in 18.3%. The breast lesions were studied with mammography, US and MRI, the latter in one case. ADH was diagnosed by strict application of Page's and lesion extent criteria. Results. Seven of 8 lesions with a core biopsy diagnosis of ADH were submitted to surgical biopsy. The diagnosis was changed in as many as 6 of 8 cases, into typical ductal hyperplasia (1 case) and carcinoma (1 papilliferous, 3 ductal infiltrating and 1 in situ lesions). ADH was confirmed in one case only. Discussion. In agreement with other authors, we found no specific radiological patterns of ADH. Moreover, the core biopsy diagnosis of ADH requires a surgical biopsy, because ADH is often associated with carcinoma. Conclusions. Surgical biopsy is needed to diagnose ADH and therefore it is useless to perform more invasive procedures than 14G core biopsy.
