The relationship between microcalcification and in situ carcinoma of the breast.

The relationship of microcalcification to lobulo-ductal dysplasia and non-invasive carcinoma was studied in 20 women with in situ carcinoma of the breast. All had microcalcification on the mammogram and in half there was also mammographic evidence of disruption of the breast structure. Three-quarters of the women presented with breast symptoms. Multifocal carcinoma was found in seven patients and the histology suggested that not all foci may progess to extensive duct infiltration or invasion. Calcification was found to occur both in carcinoma and in adjacent benign breast lesions and in three cases no evidence of calcification was found in the carcinoma, but was present in adjacent epitheliosis. The origin and distribution of microcalcification appears to be the same in epithelial hyperplasia, non-invasive carcinoma and invasive carcinoma and there may be a relationship between the amount of calcification and the activity of the epithelial cells. Microcalcification is not specific to breast cancer, but is a product of increased cellular activity in the lobulo-ductal complex and may be extruded into the surrounding interstitial tissue. This implies that microcalcification on the mammogram, particularly if sparse, demonstrates a high risk area of breast rather than a certainty of the presence of carcinoma.