Background: The conventional method of dealing with clustered mammographic microcalcification in the breast when it is of uncertain aetiology is to undertake either a short-term mammographic review or to surgically excise the abnormal area and submit it for histological examination. Stereotactic wide-bore needle biopsy (core biopsy) of microcalcifications is a suitable alternative to surgical biopsy and experience with this technique forms the basis of the present study.
Methods: Percutaneous core biopsy has been used at the Wesley Breast Clinic as a means of assessing clustered calcification in 297 cases from November 1992 to October 1995. The procedure is done under local anaesthesia as an outpatient procedure using a stereotactic attachment to a standard mammography unit.
Results: A diagnosis of frank malignancy was made on core samples in 22 cases (7.4%), and in all of these malignancy was confirmed at open surgical biopsy. In a further six women in whom the core biopsy was reported as 'suspicious of malignancy', open surgical biopsy confirmed malignancy in three women, lobular in situ carcinoma was found in two women, and atypical ductal hyperplasia in one woman. In two instances the core sample was reported as showing atypical ductal hyperplasia and in those cases, this was confirmed at open surgical biopsy. In 265 cases (89%) the histology of the core revealed appearances of benign breast tissue. Open surgical biopsy has been undertaken in only six of these cases, but in all instances the histology has confirmed a benign process. In the two remaining cases, the procedure was considered to be technically unsatisfactory, and open surgical biopsy was recommended because of doubt about the appearance of the microcalcification. In both instances, malignancy was demonstrated.
Conclusions: Core biopsy of clustered mammographic microcalcification of uncertain aetiology is recommended as a satisfactory and reliable alternative to open surgical biopsy. It is less expensive, can be done quickly, produces few complications, and does not produce subsequent mammographic distortion.