Use of the von Kossa stain in identifying occult calcifications in breast biopsies

In a two-year series of more than 300 mammographic-directed biopsies with radiographic calcifications, calcium deposits could not be identified in approximately 10% with the use of routine hematoxylin and eosin (H and E) stains. In most of these cases, calcifications, sometimes in surprising amounts, could be identified by use of the von Kossa stain. These included calcium deposits in acinar secretions (nine), cyst fluid (four), ductal ectasia (six), and papillomatosis (five). It would appear that the von Kossa stain is more sensitive for calcium than hematoxylin and is a useful technique when combined with specimen radiography in providing satisfactory radiologic-pathologic correlation.